DVS_Bericht_393LP

2024
PROCEEDINGS
ITSC 2024
International Thermal Spray
Conference and Exhibition
Conference Proceedings
and Poster Sessions

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ITSC 2024
International Thermal Spray
Conference and Exhibition
Conference Proceedings
and Poster Sessions
of the Conference in Milan/Italy on
April 29 – May 1, 2024
Organizers:
• DVS – German Welding Society
• ASM International – Thermal Spray Society (TSS)
• DVS Media GmbH
Supporting Partners
Media Sponsors

Bibliographic information published by the Deutsche Nationalbibliothek
The Deutsche Nationalbibliothek (German National Library) lists this publication in the
Deutsche Nationalbibliografie; detailed bibliographic data are available on the Internet at
http://dnb.d-nb.de.
DVS-Berichte Volume 393
ISBN 978-3-96144-263-8 (Print)
ISBN 978-3-96144-264-5 (E-Book)
ISBN 978-3-96144-265-2 (USB Flash Drive)
The conference abstracts are printed in form of manuscripts.
All rights, also for translation, are reserved. Reprint and fotomechanical reproduction (i. e. photo
copy, micro copy etc.) of this volume or of parts of it only with approval of DVS Media GmbH,
Düsseldorf.
© DVS Media GmbH, Düsseldorf ⋅ 2024
Print: Print Media Group GmbH & Co. KG, Hamm

Preface
ITSC 2024: ADVANCING THERMAL SPRAY TECHNOLOGY – Innovations,
Applications and Sustainability
Many economies are facing fundamental structural challenges. In addition to the transformation of
manufacturing processes, the energy transition and other location factors, the geopolitical turning point
should also be mentioned. This has led to higher energy- and raw material prices, among other things. The
direct consequences for companies are diversified supply chains, investments in renewable energies and a
transformation of manufacturing processes. Cost and production optimization are the main drivers here.
These requirements are also clearly noticeable in the field of thermal spraying.
The ITSC 2024 - International Thermal Spray Conference and Exhibition will once again summarize these
latest global developments and will offer solutions for current or future applications. For more than 20 years,
ITSC has established itself as the world‘s leading event for users, service providers and manufacturers.
What ITSC offers is as fascinating as the technology itself. Parallel to the ITSC conference – various event
formats will be presented to inspire visitors from all sectors for the fascinating thermal spray, but also for
plasma and laser based cladding technologies. These technologies have also become more and more
interesting for surfacing solutions. Cladding also fulfills many requirement specifications in an excellent way.
Functional layer systems with electrically conductive and electrically insulating properties as well as layer
systems with catalytic properties are becoming increasingly important as a result of new applications. ITSC
2024 provides an overview of these coating systems, which are not least driven by the energy and mobility
transition. ITSC 2024 will also feature the latest improvements in the field of additive manufacturing (AM).
For that, thermal spray, as well as cladding technologies, offer a magnificent technological basis for new AM
applications.
One other highlight of the technical program will be again the Session “Young Professionals”. ITSC 2024 is
supporting young talents becoming part of the worldwide thermal spray family. On the first day, the Young
Professional Session will take place, in which the up-and-coming talents will present their content to the
audience in short, snappy talks. The audience will decide live on site who will win the coveted Young
Professional Award!
To offer newcomers and interested end users an introduction in thermal spray technology, the session
“Thermal Spray in a Nutshell” will fulfill all expectations for the second time. The lectures are prepared in this
format for an audience that is new to the field of thermal spraying and want a well-founded introduction from
the experts! The “Industrial Forum” is another characteristic of ITSC. This Forum will include practical
demonstrations on industry related topics, products and solutions. Both sessions are also available for EXPO
ONLY visitors!
Last but not least the “Three-day Exposition” is a permanent part of the event. If you are looking for new
products and services, have questions or need answers, then ITSC 2024 is the best place for you! More than
70 leading companies already confirmed to participate.
ITSC is organized by DVS – German Welding Society and DVS – Publishing House in cooperation with the
ASM – Thermal Spray Society and supported by GTS – Association of Thermal Sprayers. All partners do
their best to fulfill and surpass all attendees expectation!
ITSC will take place in Milan, the metropolis in northern Italy’s Lombardy, the world-famous center for fashion
and design on April 29 to May 1, 2024. More than 320 contributions from 32 countries and all other event
highlights stand for a promising and unforgettable event.
Sono particolarmente impaziente di darvi il benvenuto a Milano!
Jens Jerzembeck
DVS – German Welding Society

Committees and Endorsing Sponsors
General Chairs:
W. Krömmer* The Linde Group (DE)
R. Lima National Research Council (CA)
*In charge of the abstract review and programming and
as judges regarding the Best Paper Awards
DVS Representatives:
A. Barth Höganäs GmbH
R. Enžl Oerlikon Metco AG (CH)
F. Ernst KS HUAYU AluTech GmbH (DE)
F. Gärtner Helmut-Schmidt-University (DE)
T. Grund Chemnitz University of Technology
(DE)
S. Hartmann obz innovation gmbh (DE)
H. Heinemann RWTH Aachen University (DE)
X. Huang TSCC Thermal Spray Committee of
Chinese Surface Engineering
Association (CN)
J. Jerzembeck DVS – German Welding Society (DE)
T. Klassen Helmut-Schmidt-University (DE)
T. Königstein GTV Verschleißschutz GmbH (DE)
M. Knoch Plasmatic Franken GmbH (DE)
T. Lampke Chemnitz University of Technology
(DE)
T. Linke Nemak Dillingen GmbH (DE)
E. Lugscheider RWTH Aachen University (DE)
H. Maier Leibniz University (DE)
G. Mauer Forschungszentrum Jülich GmbH
(DE)
K. Möhwald Leibniz University (DE)
M. Öte Schaeffer Technologies AG & Co. KG
(DE)
F. Prenger Grillo Werke AG (DE)
C. Rupprecht Technische Universität Berlin (De)
F. Schreiber DURUM Verschleiss-Schutz GmbH
(DE)
S. Tank DVS Media GmbH (DE)
F. Tiggemann Flowserve Flow Control GmbH (DE)
W. Tillmann University of Dortmund (DE)
R. Vaßen Forschungszentrum Jülich GmbH
(DE)
Technical Chairs:
K. Bobzin* RWTH Aachen University (DE)
A. Ang Swinburne University of Technology (AU)
ASM-TSS Representatives:
N. Curry Thermal Spray Innovations (AT)
S. Fowler-Hutchinson SAINT-GOBAIN (US)
E. Irissou National Research Council (CA)
C. Kay Hannecard Roller Coatings, Inc. (US)
H. Koivuluoto Tampere University of Technology
(FI)
J. Koppes Thermal Spray Technologies (US)
K. Laul Delta Airlines (US)
W. Lenling Thermal Spray Technologies (US)
R. Lima National Research Council (CA)
A. McDonald University of Alberta (CA)
C. Moreau Concordia University (CA)
C. Raval Hannecard Roller Coatings, Inc. (US)
K. Shinoda National Institute of Advanced
Industrial Science and Technology
(JP)
K. Sridharan University of Wisconsin (US)
A. Vackel Sandia National Laboratories (US)
J. Veilleux Universite de Sherbrooke (CA)
J. Villafuerte Centerline (CA)
Sponsors:
Alloy Coating Supply (ACS) (US)
C&M Technologies GmbH (DE)
GTV Verschleißschutz GmbH (DE)
Höganäs GmbH (DE)
Metallizing Equipment Co. PVT Ltd. (IN)
Oerlikon metco AG (CH)
Saint-Gobain Coating Solutions (FR)
Corporate Supporters:
DURUM Verschleiss-Schutz GmbH (DE)
INDO-MIM Private Limited (IN)
Linde Advanced Material Technologies, Inc. (DE)

Table of contents
Preface
Time Schedule
Proceedings
Power Storage
Development of Dense and Low Oxide Titanium Coatings for PEMWE Application ........... 1
K. Bobzin, H. Heinemann, E. Olesch, K. Radermacher
Plasma-spray deposition of Na3Zr2Si2PO12 electrolyte for high
performance all solid-state sodium-ion battery ................................................................... 8
X.-C. Bu, N. Chen, X.-T. Luo, C.-J. Li
Automotive Industry
Cold Atmospheric Plasma Metallization of Power Semiconductor
Devices with CuSn Pseudo-Alloys for Diffusion Soldering ................................................ 17
M. Ockel, A. Gökçen, B. Ottinger, M. Petersen, C. Voigt, J. Franke
Laser Cladding I
Comparative Studies of SUS316L Layer Deposited by Conventional
Laser Cladding and Extreme High Speed Laser Cladding ................................................ 27
T. Izumi, A. Yano, and M. Arai
Further Applications
Thermally sprayed coatings for dynamic magnetic data storage ...................................... 34
M. Nicolaus, M. Arndt, M. Wurz, K. Möhwald, H. J. Maier
Young Professionals Session
Subsurface Weave Pattern Influences on Cold Spray Deposits onto Woven Fiber
Reinforced Composites ……….……………………………………………………………….. 40
M. Kaminskyj, N. Mennie, N. Singh, B. Koohbor, F. M. Haas
Techno-Economic Assessment of Utilization of Cold Spraying Process for Fabrication
of Resistive Heating Elements for Temperature Protection of Steel Pipes ....................... 49
M. Rezvani Rad, P. Menghesha, M. O. Jarligo, A. McDonald
Soilless Cultivation via Thermal Spraying ........................................................................ 59
Flammspritzen - HVOF - Verschleissschutz - Korrosionsschutz
P. Biswal, M. Hauer, L. Möhrke, A. Gericke, S. Rasche, H. Schinkel, K.-M. Henkel
www.cremer–beschichtungen.de
info@cremer-beschichtungen.de
Calibration of the Critical Velocity in Cold Gas Spraying................................................... 67
L. Wiehler, J. Capan, Z. Arabgol, C. Huang, A. List, F. Gärtner, T. Klassen
AZ_Cremer_176x62mm.indd 1 16.03.2017 13:43:34

Thermally sprayed coatings for dynamic magnetic data storage ...................................... 34
M. Nicolaus, M. Arndt, M. Wurz, K. Möhwald, H. J. Maier
Young Professionals Session
Subsurface Weave Pattern Influences on Cold Spray Deposits onto Woven Fiber
Reinforced Composites ……….……………………………………………………………….. 40
M. Kaminskyj, N. Mennie, N. Singh, B. Koohbor, F. M. Haas
Techno-Economic Assessment of Utilization of Cold Spraying Process for Fabrication
of Resistive Heating Elements for Temperature Protection of Steel Pipes ....................... 49
M. Rezvani Rad, P. Menghesha, M. O. Jarligo, A. McDonald
Soilless Cultivation via Thermal Spraying ........................................................................ 59
P. Biswal, M. Hauer, L. Möhrke, A. Gericke, S. Rasche, H. Schinkel, K.-M. Henkel
Calibration of the Critical Velocity in Cold Gas Spraying................................................... 67
L. Wiehler, J. Capan, Z. Arabgol, C. Huang, A. List, F. Gärtner, T. Klassen
Effects of Plume Targeted Cooling on Residual Stress in Controlled Atmosphere
Plasma Sprayed Coatings ............................................................................................... 74
E. E. Peleg
Aviation Industry I
Processing and suspension plasma spray deposition of ZrO2-based
ceramic materials for thermal barrier coatings ……………………………………………... 75
M. C. Galeano Camacho, H. Ageorges, J. Muñoz-Saldaña
Medical Industry
Cold Spray of Ta-Ag Composites: Correlation Between Microstructure and
Antibacterial Properties .................................................................................................... 83
P. Yu, G. Perumal, K. J Genoud, R. Lupoi, S. Yin, F. J O'Brien, D. Brabazon
Modelling & Simulation I
Understanding the Effect of Mo Concentration on the Strength of AlCoCrFeMo
High-Entropy Alloy Using Atomistic Simulations ............................................................ 100
N. Jalal, M. O. Jarligo, A. McDonald, W. Stroberg
Laser Cladding II
Investigations on laser cladding of tin-bronze on steel .................................................. 108
H. Freisse, E. Isère, T. Schudeleit, F. Rippa, D. Keller
COAXquattro: A Versatile High-Power Multi-Wire Laser Cladding Technology ............. 114
F.-L. Toma, H. Hillig, M. Kaubisch, I. Shakhverdova, M. Seifert, F. Brückner
Repair & Recycling
Trajectory Optimization for Repair by Robot-guided Cold Spray ................................... 123
M. Lewke, H. Wu, A. List, F. Gärtner, T. Klassen, A. Fay
Numerical simulation of the shaft parts repairing process by laser metal deposition
technique ....................................................................................................................... 130

COAXquattro: A Versatile High-Power Multi-Wire Laser Cladding Technology ............. 114
F.-L. Toma, H. Hillig, M. Kaubisch, I. Shakhverdova, M. Seifert, F. Brückner
Repair & Recycling
Trajectory Optimization for Repair by Robot-guided Cold Spray ................................... 123
M. Lewke, H. Wu, A. List, F. Gärtner, T. Klassen, A. Fay
Numerical simulation of the shaft parts repairing process by laser metal deposition
technique ....................................................................................................................... 130
Y. Meng, M. Arai, T. Izumi
Is particle hardness the decisive factor for adhesion in cold spray? .............................. 138
M. Steierl, F. Gärtner, T. Klassen
Characterization & Testing Methods I
Exploring the Crack Propagation Behaviour in Suspension Plasma Sprayed
Thermal Barrier Coatings: An In-Situ Three-point Bending Study in
Scanning Electron Microscope ...................................................................................... 139
M. Amer, N. Curry, M. Arshad, Q. Hayat, V. Janik, J. Nottingham, M. Bai
Performance of Thermally Sprayed Inconel Coatings in Erosion-Corrosion
Conditions of Biomass-Fired Boilers .............................................................................. 152
R. Verma, G. Kaushal
The influence of incursion rate on abradability of AlSi-hBN abradable seal coating ...... 159
T. Liu, J. Liu, D. Zhang, Y. Hou
Ceramic Coatings
Understanding the formation of different surface structures of hydrophobic
ceramic coatings deposited in the SPAPS process and SPVPS process ...................... 166
P. Xu, X. Sui, T. W. Coyle, L. Pershin, J. Mostaghimi
Development and understanding of CMAS coating on YSZ using APS technique ........ 176
A. Roy, F. B. Ettouil, R. S. Lima, C. Moreau
Corrosion Protection I
Comparative Analysis of Cold Sprayed and HVOF Sprayed NiCrTiCRe coating
on T22 Boiler Steel in Thermal Power Plant Boiler Environment ................................... 185
N. Bala, H. Singh, S. Prakash
Thermal Spray in a Nutshell I
Plasma spraying − from single to multiple electrodes .. .................................................. 194
G. Mauer
Suspension spraying ...................................................................................................... 195
F.-L. Toma
Thermal Spray in a Nutshell II
Cold spraying ................................................................................................................. 196
F. Gärtner

The influence of incursion rate on abradability of AlSi-hBN abradable seal coating ...... 159
T. Liu, J. Liu, D. Zhang, Y. Hou
Ceramic Coatings
Understanding the formation of different surface structures of hydrophobic
ceramic coatings deposited in the SPAPS process and SPVPS process ...................... 166
P. Xu, X. Sui, T. W. Coyle, L. Pershin, J. Mostaghimi
Development and understanding of CMAS coating on YSZ using APS technique ........ 176
A. Roy, F. B. Ettouil, R. S. Lima, C. Moreau
Corrosion Protection I
Comparative Analysis of Cold Sprayed and HVOF Sprayed NiCrTiCRe coating
on T22 Boiler Steel in Thermal Power Plant Boiler Environment ................................... 185
N. Bala, H. Singh, S. Prakash
Thermal Spray in a Nutshell I
Plasma spraying − from single to multiple electrodes .. .................................................. 194
G. Mauer
Suspension spraying ...................................................................................................... 195
F.-L. Toma
Thermal Spray in a Nutshell II
Cold spraying ................................................................................................................. 196
F. Gärtner
Isolating Coatings
Enhanced Coating Deposition by Development of Oxide Shelled Aluminium Nitride .... 197
K. Bobzin, H. Heinemann, E. Olesch, A. Aslankaya
Power Generation
Properties of Novel Partially Amorphous Fe-based Thermal Barrier Coatings
under the Influence of Cryogenic Temperature and Hydrogen ...................................... 204
M. Hauer, L. Möhrke, P. Biswal, O. Brätz and A. Gericke, B. Allebrodt, K.-M. Henkel
Refurbishment Process of Platform Combustion System of SGT5-8000H .................... 213
B. Burbaum, I. Just, W. Remmert, M. Gralki
Air plasma-sprayed MCrAlY coatings with low oxide content enabled by
adding a deoxidizer ........................................................................................................ 221
Y.-S. Zhu, X. Xue, X.-T. Luo, C.-J. Li
Hot corrosion behaviour of yttria stabilized zirconia and La2Ce2O7
based dual coatings ....................................................................................................... 228
A. Pakseresht, A. Suyambulingam, A. Sekar, M. Parchovianský
Maritime Industry & Offshore Technologies
Data-Driven Mitigation of Process Fluctuations in Wire-Arc Spraying ........................... 233

Hot corrosion behaviour of yttria stabilized zirconia and La2Ce2O7
based dual coatings ....................................................................................................... 228
A. Pakseresht, A. Suyambulingam, A. Sekar, M. Parchovianský
Maritime Industry & Offshore Technologies
Data-Driven Mitigation of Process Fluctuations in Wire-Arc Spraying ........................... 233
K. Bobzin, H. Heinemann, L. M. Johann
In-field Repair for Maritim Hardware Using High-Pressure Cold Spray ......................... 240
H. P. Höll, K. Klus, A. T. Nardi, R. M. Gerani, D. Stanley, T. J. Eden
Cavitation Erosion in HVOF Thermally Sprayed WC-NiCrBSi Coatings ........................ 248
A. Algoburi, R. Ahmed, V. Kumar
Aviation Industry II
Effect of Pt additions on the bond coats of the Thermal Barrier Coating systems
in aero gas turbine engines ............................................................................................ 256
T. B. Usubaliyev, A. S. Samedov, P. Sh. Abdullayev
New Processes
Influence of Substrate Patterns on the Coating Microstructure in
Aerosol-deposited Alumina Coatings ............................................................................. 257
Z. Yang, A. Dolatabadi, T. W. Coyle
In-Situ SEM Observation of Mechanical Failure of Hybrid Plasma Spray Coatings ....... 266
R. Musalek, T. Tesar, J. Minarik, R. Genois, J. Dudik
A new approach for the application of highly reactive metals ........................................ 278
M. Rodriguez Diaz, M. Szafarska, René Gustus, K. Möhwald, H. J. Maier
HVOF/HVAF-Spraying
Gas-fuel HVOF and its influencing factors: introducing the total gas flow ...................... 284
C. Hambrock, W. Rannetbauer, S. Hubmer, R. Ramlau
Highly Porous Titanium Coatings for Proton Exchange Membrane Water
Electrolysis Application by HVOF ..................................................................... ….……. 291
K. Bobzin, L. Zhao, H. Heinemann, E. Olesch
Suspension Spraying
Physical mechanisms in plasma spray processing of suspensions ............................... 298
A. Chergui, C. Lebot, V. Rat, G. Mariaux, A. Denoirjean
Parameters influencing the photocatalytic activity of suspension sprayed
ZnO-TiO2 coatings ........................................................................................................ 310
A. Meyer, F.-L. Toma, O. Kunze, A. Potthoff, C. Leyens
Gas & Fuel Industry
An optical and metallurgical comparison of chrome free and chrome containing
Al-Si slurry diffusion coatings for Gas Turbine Applications ........................................... 319
S. Higgins, T. D. A. Jones, Q. Zhao

Parameters influencing the photocatalytic activity of suspension sprayed
ZnO-TiO2 coatings ........................................................................................................ 310
A. Meyer, F.-L. Toma, O. Kunze, A. Potthoff, C. Leyens
Gas & Fuel Industry
An optical and metallurgical comparison of chrome free and chrome containing
Al-Si slurry diffusion coatings for Gas Turbine Applications ........................................... 319
S. Higgins, T. D. A. Jones, Q. Zhao
Study the Impact of Process Parameters of Laser Cladding Nickel-Chromium
Alloy Powder on Substrate Melted Areas ....................................................................... 325
R. A. Ahmed, R. S. Khan, M. M. Qahtani, A. Alsayoud, A. S. Bukhari
Pre- & Post-Treatment
Influence of laser fusing parameters on the microstructure evolution of thermally
sprayed self-fluxing NiCrBSiFe coatings ........................................................................ 336
B. Preuß, T. Lindner, G. Töberling, S. Kaur and T. Lampke1
Effect of surface preparation by laser texturing in thermal spraying on the fatigue
life of the Ti-6Al-4V alloy ................................................................................................ 343
E. Pegane-Vingadas, M. Chaussumier, A. Soveja, S. Costil
Improved adhesion of plasma-sprayed ceramic coatings on textured
ceramic substrates ......................................................................................................... 356
T. Ferrasse, S. Costil, G. Darut, B. Bouteiller, M. C. Auscher
Functional Coatings
Comparative Analysis of Mechanical Properties of Thermally Sprayed Cu
and Zn Coatings on Fibre-Reinforced Plastic for Enhanced EMC Applications ……...... 365
J. Gebauer, S. Scheitz, C. Rothe, A. Paul, P. Kanagarajah, M. Reif
Microstructure evolution and oxidation behavior of thermal barrier coatings
with varying cold sprayed bond coats after isothermal heat treatments ......................... 376
S. Dosta, C. R. C. Lima, V. Crespo, J. Nin, G. Clavé
Corrosion Protection II
Investigation on oxidation and interdiffusion in the systems of aluminiferous
coatings and superalloys ............................................................................................... 382
X. Sun, J. Moverare, X.-H. Li, R. L. Peng
Tribology behaviour of HVAF and HVOF sprayed WC-CoCr coatings
on light alloys ................................................................................................................. 386
T. Owoseni, M. Gupta, I. Mare, T. Varis
The impact of YSZ powder morphology and chemical composition on the efficacy
of Thermal Barrier Coatings (TBCs) used in industrial applications ............................... 398
G. Bolelli, S. Bursich, G. Cavazzini, L. Lusvarghi, S. Morelli, C. Ricci, E. Rossi, M. Sebastiani, P. Puddu

Metals Processing
Optimization of the Ni-coating geometry and microstructure of large surfaces
by laser cladding on cast-iron molds used in glass industry .......................................... 399
F. Bourahima, T. Lauridant, C. Guasch, T. Baudin, A.-L. Helbert
High-Speed Laser melt Injection for Reinforcing Skin-Pass Rolls .................................. 409
P. Warneke, A. Bohlen, T. Seefeld
Cold Gas Spraying I
Comprehensive Characterization of Annealed Coatings: Investigating Roughness
and Wear Performance through Wear Testing and Analysis ......................................... 418
N. Sheibanian, R. Sesana, S. Özbilen, R. Lupoi
Characterization & Testing Methods II
Fast and non-destructive mechanical characterization of coatings from thermal
spraying and laser cladding: automated surface acoustic wave spectroscopy
as a new tool for quality control and research ................................................................ 427
M. Zawischa, S. Makowski
Characterizing deformation by positron annihilation spectroscopy: cold spray vs.
high-pressure torsion ..................................................................................................... 437
J. Cizek, J. Medricky, F. Stefanik, F. Lukac, O. Melikhova, J. Cizek
A micro-spectroscopic approach to characterizing residual stresses and
subsurface modifications due to high-speed collision during cold spray
deposition of metals on glass substrates ....................................................................... 444
A. K. Elkholey, D. de Ligny, R. N. Raoelison, C. Verdy, P. Bertrand, C. Langlade
Data Driven Models & Artificial Intelligence
Physics-Informed Neural Networks for Predicting Particle Properties in
Plasma Spraying ............................................................................................................ 452
K. Bobzin, H. Heinemann, A. Dokhanchi
Databased Optimization of Coating Characteristics – Challenges and
Possible Solution ........................................................................................................... 459
BodyClad® High Wear Performance
W. Rannetbauer, C. Hambrock, S. Hubmer, R. Ramlau
Claddings - Wear Parts - Wear Plates - Maintenance - Sustainable
Additive Manufacturing I
Towards an integrated modular cold spray additive manufacturing system .................... 469
W. Li, H. Wu, S. Liu, H. Liao, S. Costil, S. Deng
An Investigation on the Effect of Deposition Technique on Microstructural
and EUROMAT Mechanical GmbH Properties of Hermann-Hollerith-Straße WC-17Co Deposited 6 Using t +49Direct 2401 607 2866 Energy e input@euromat.de
Deposition
Industrial Surface
(DED)
Solutions
and High-Velocity
52499 Baesweiler
Oxygen Fuel (HVOF)
f +49 2401
...........................................
607 2855
w www.euromat.de483
T. Grabowski, F. Azarmi, M. McDonnell
Engineering · Production · Technology

subsurface modifications due to high-speed collision during cold spray
deposition of metals on glass substrates ....................................................................... 444
Powders, Wires, Suspensions
A. K. Elkholey, D. de Ligny, R. N. Raoelison, C. Verdy, P. Bertrand, C. Langlade
Data Driven Models & Artificial Intelligence
Physics-Informed Neural Networks for Predicting Particle Properties in
Plasma Spraying ............................................................................................................ 452
K. Bobzin, H. Heinemann, A. Dokhanchi
Databased Optimization of Coating Characteristics – Challenges and
Possible Solution ........................................................................................................... 459
W. Rannetbauer, C. Hambrock, S. Hubmer, R. Ramlau
Additive Manufacturing I
Towards an integrated modular cold spray additive manufacturing system .................... 469
W. Li, H. Wu, S. Liu, H. Liao, S. Costil, S. Deng
An Investigation on the Effect of Deposition Technique on Microstructural
and Mechanical Properties of WC-17Co Deposited Using Direct Energy
Deposition (DED) and High-Velocity Oxygen Fuel (HVOF) ........................................... 483
T. Grabowski, F. Azarmi, M. McDonnell
From Anticosti Island’s ‘Deep Time’ to A Cold Spray Additive Manufacturing
Art Creation .................................................................................................................... 495
A. Nastic, B. Jodoin, C. Fitzgerald, S. Desaulniers, L. Pouliot, F. Caio, D. Macdonald, A. Duval, G. Dubois,
V. Tessier, C. Etienne
Additive Manufacturing II
Experimental and numerical study of the spattering dynamic mechanisms in
selective laser melting .................................................................................................... 508
S. Qin, W. Zhang, S. Yin, S. Lei
The effect of powder particle size on mechanical and fracture properties of cold
sprayed Al ...................................................................................................................... 514
O. Kovarik, F. Wick, L. Wiehler, C. Huang, J. Cizek, A. List, F. Gärtner, T. Klassen
Cold Gas Spraying II
Improving Adhesion Strength by Laser Assisted Cold Spraying of Mild Steel ............... 520
F. Caio, A. Nascimento, Luc Pouliot, D. MacDonald, J-G. Legoux, D. Poirier, M. Martin
Evaluation of lightning resistance property of thermoplastic CFRP metallized
by low-pressure cold spray ............................................................................................ 521
H. Saito, W. Kai, T. Funaki, Y. Ichikawa, K. Ogawa
Studies of Particle Deformation and Microstructure Evolution Using High Strain
Rate Particle Compression Test .................................................................................... 528
G. J. Na, A. Hashizume, Q. Tang, M. Hassani, Y. Ichikawa
Cold Gas Spraying III
In-Situ Studies of Impact-Induced Bond Strength at the Single Particle Scale .............. 535
Q. Tang, M. Hassani

Studies of Particle Deformation and Microstructure Evolution Using High Strain
Rate Particle Compression Test .................................................................................... 528
G. J. Na, A. Hashizume, Q. Tang, M. Hassani, Y. Ichikawa
Cold Gas Spraying III
In-Situ Studies of Impact-Induced Bond Strength at the Single Particle Scale .............. 535
Q. Tang, M. Hassani
Powders, Wires, Suspensions
Plasma-Sprayed Bulk-like Ni-based Alloy Coating Enabled by Boron-containing
Powder Design with exceptional High Tensile Strength ................................................. 536
C.-Jiu Li, X.-Y. Dong, J.-J. Song, Y.-S. Zhu, X.-T. Luo, L. Zhang
Process Diagnostics, Sensors & Controls I
Offline robot programming for generating coating paths quickly and accurately ............ 543
S. Schneebeli, D. A. Karandikar
Opportunities and Limitations of a Holistic Process Monitoring System
for Arc Processes .......................................................................................................... 549
S. Weis, S. Brumm, R. Grunert, M. Halmaghi, J. Morgenschweis, J. Bosler
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Modelling & Simulation II
Computational Quantitative Validation of Multiphase High-Entropy Alloy Coating
Using Non-Equilibrium CALPHAD Simulation ................................................................ 557
E. Bosi, A. Meghwal, S. Singh, P. Munroe, C. C. Berndt, A. S. M. Ang
Tribological Coatings I
A Comparative Investigation of Feedstock Materials on Multiple Properties of
HVOF-Formed Cr3C2-NiCr Coatings: Size Effects of Powders and Carbides
on Sliding Abrasive Wear Behavior ............................................................................... 558
X. Ma, P. Ruggiero
Hard-Facing Coatings for Agriculture Tools ................................................................... 570
L. Möhrke, M. Hauer, P. Biswal and A. Gericke
Dynamic impact wear behavior of HVOF sprayed hardmetal coatings .......................... 580
Š. Houdková, J. Duliškovič, M. Vostřák, T. Taranda, O. Skála, R. Musilová, J. Daniel, L.-M. Berger
Metal Coatings
Enhancing the Optimized HEA Bond Coating in TBC Systems via HVAF Technique ... 594
H. Shahbazi, R. S. Lima, P. Stoyanov, C. Moreau
Tribological Coatings II
Tribology of self fluxing ceramic coatings prepared using external feeding
hybrid plasma spraying .................................................................................................. 611
T. Tesar, R. Musalek, F. Lukac, J. Walter, L. Cvrcek, J. Cech
The Performance of Metal Based Abradable Sealing Coatings Based on Peeling
Medium Particle Structure Design ................................................................................. 617
D. Guo, J. Liu, T. Liu, C. Wu
Process Diagnostics, Sensors & Controls II
In Situ Spray Bead Acquisition and Analysis for Coating Thickness Predictions ........... 623
U. Hudomalj, I. Aschwanden, L. Weiss, M. Nabavi, K. Wegener

Applications – Automotive Industry
Poster Sessions
Analysis of Different High-Velocity Thermally Sprayed Coatings to Recover
AISI H13 High-Pressure Die-Casting Molds .................................................................. 632
A. R. Mayer, E. B. Sabino, H. D. C. Fals, A. G. M. Pukasiewicz,
W. R. de Oliveira, S. Björklund, S. Joshi
Applications – Aviation Industry
Deposition and Characterization of Thermally Sprayed Metallic Coatings onto
Polymer Reinforced Carbon Fiber Composites .............................................................. 643
D. S. Ghuman, M.-L. Cliche, B. C. N. M. de Castilho, F. B. Ettouil, C. Moreau, C. Pan, P. Stoyanov
Applications – Electronics and Sensors
Fluid Velocity Sensors Made by Thermal Spray ............................................................ 652
A. Hanna, S. Chandra
Applications – Medical Industry
Mold-resistant air filters embedded with copper particles .............................................. 660
L. Pershin, S. Delage, M. Zhang, M. Ringuette, J. Mostaghimi
Antibacterial surface coatings by Plasma Spray (APS/SPS) and Physical
Vapor Deposition (PVD) processes: a comparative approach ....................................... 663
L. Youssef, A. Prorot, L. Gnodé, T. Maerten, S. Belvèze, C. Acikgoz, N. Manninen, V. Rat, A. Vardelle, A. Denoirjean
Applications – Power Generation
Improvements in cavitation and slurry wear erosion of Inconel 718 laser
cladding through the NiNb addition ........................................................................... …. 670
H. D. C. Fals, S. R.F. Sabino, A. G.M. Pukasiewicz
Equipment/Consumables – Industrial Automation & Robotics
Visual Odometry for Mobile Material Deposition Systems using
RGB-D Cameras ......................................................................................... ….………… 681
..
H. Saadati Nezhad, M. Contreras, A. McDonald, E. Hashemi
Equipment/Consumables – Process Diagnostics, Sensors & Controls
Understanding the impact of binary plasma gas mixtures in plasma spraying ............... 689
K. Bobzin, H. Heinemann, M. Erck, K. Jasutyn
Properties and Materials – Metal Coatings
Effect of the Test Method on the Resulting Adhesion of the Coating ............................. 696
Ž. Dlouhá

Properties and Materials – Tribological Coatings
Design and Development of Cost-Effective Equipment for Tribological Evaluation
of Thermally Sprayed Abradable Coatings .................................................................... 704
K. Bertuol, F. R. E. Rivadeneira, B. C. N. M. Castilho, C. Moreau, P. Stoyanov
Thermal Spray and other Processes – Additive Manufacturing
Investigation of Mechanical Properties of Cobalt Chromium Additively
Manufactured Using Direct Energy Deposition: Experimental Study and
Finite Element Analysis .................................................................................................. 712
D. Smith, P. Pickett, T. Grabowski, J. Thorpe, F. Azarmi
Thermal Spray and other Processes – Cold Gas Spraying
Heat treatment effects on structural and mechanical features of cold sprayed
3D Aluminium part ......................................................................................................... 724
M. Sokore, S. Deng, H. Liao, R. N. Raoelison
Cold-Sprayed Aluminum Alloys: Exploring the Differences Between 6061
and 7075 ........................................................................................................................ 732
K. Rafiee, E. Barbosa de Melo, P. Vo, M.H. Martin, S. Yue
Thermal Spray and other Processes – Modeling & Simulation
Investigation of the pore formation during the cold spray additive manufacturing
of a bulk aluminum part .................................................................................................. 743
M. Sokore, S. Deng, H. Liao, R. N. Raoelison
Nozzle geometry optimization for cold spray applications by using
3D-CFD calculations ...................................................................................................... 751
J. Gutiérrez de Frutos, A. List, F. Gärtner, T. Klassen
Thermal Spray and other Processes – Plasma Spraying
Influence of Concentrated Solar Power on Plasma Sprayed Hybrid Thermal
Barrier Coatings ............................................................................................................. 759
J. Dudik, I. Hulka, T. Tesar, F. Lukac, R. Musalek
Thermal Spray and other Processes – Pre- & Post-Treatment
Lightblast ....................................................................................................................... 768
T. Wanski, P. Herwig, J. Hauptmann
Authors and Co-Authors ……………………………………………………………….. 773

Development of Dense and Low Oxide Titanium Coatings for PEMWE
Application
K. Bobzin, H. Heinemann, E. Olesch, K. Radermacher*
Surface Engineering Institute (IOT), RWTH Aachen University, Aachen, Germany
A key technology to minimise CO2-emissions is the production of hydrogen from water electrolysis. The proton
exchange membrane water electrolysis (PEMWE) consists of a stacked system out of bipolar plates (BPP),
porous transport layers (PTL) and a membrane electrode assembly (MEA). Research activities are ongoing to
minimize material input, reduce costs and increase the performance. For example, the BPP on the anodic side
of the stack is currently manufactured of bulk titanium and its substitution by a Ti-coated steel substrate is
economically interesting. The main requirements for the BPP-coating are a high coating density, a low
electrical resistance and a long lifetime in a harsh electrochemical environment. Coating application on
substrates of s ≤ 0.5 mm thickness is conducted with three thermal spraying technologies: Cold Gas Spraying
(CGS), High Velocity Air-Fuel (HVAF) spraying and High Velocity Oxy-Fuel (HVOF). Substrate preparation is
examined as well. Coating development is conducted with regards to coating thickness, density and oxidation.
The examination of coatings includes roughness analysis, structural and chemical analysis. The results allow
an evaluation of the suitability of thermally sprayed Ti-coatings by the structural properties for the PEMWE
application. Among the three tested processes, CGS is the most suitable for this type of application. The three
chosen thermal spraying processes are examined for coating application on metal sheets in context of PEMWE
for the first time.
1 Introduction
The use of thermally sprayed coatings for water electrolysis to produce hydrogen is known in the context of
alkaline water electrolysis (AWE) and solid oxide electrolysis cell (SOEC). The proton exchange membrane
water electrolysis (PEMWE) is another electrolysis variant which is characterised by a higher hydrogen
production rate under smaller cell dimensions [SGG11].
The PEMWE entails a stacked system out of bipolar plates (BPP), porous transport layers (PTL) and a
membrane electrode assembly (MEA). The BPP is a structural cell component responsible for fluid transport,
electrical conductivity and mechanical stability of the electrochemical cell. Typically, BPPs are manufactured
from commercially pure titanium sheets with a thickness of 0.3 mm ≤ s ≤ 1 mm. In order to facilitate the
manufacturing process and to reduce costs, steel-based BPPs are currently investigated. Because of the acidic
conditions in the PEMWE cell and the high cell voltage of of U = 2 V, corrosion of the steel-based BPP is to be
expected. In order to protect the steel-based BPP from corrosion, a corrosion protection coating with a high
coating density as a barrier between steel and electrolyte should be deposited on the steel surface. According
to the Pourbaix diagrams [Pou74], titanium, tantalum and niobium are the most suitable materials for this type
of protection coating under the PEMWE conditions.
The coating development for potential corrosion protection of the BPP is yet at the beginning. Physical vapor
deposited (PVD) coatings have been examined for PEMWE application since they have been established in
fuel cell (PEMFC) application. In Langemann et al. [LFM+15] PVD-coatings of Au and TiN were examined.
Both coatings were infiltrated with the electrolyte because of pin holes in the PVD-coating causing corrosion
of the underlying substrate.
In Rojas et al. [RSS+21] single and multilayer coating architectures of CrN and TiN in combination with different
chemical resistant steels were investigated. Regarding CrN, the protective passivation layer of Cr2O3 was
destroyed at electrochemical potentials of E > 1 V vs NHE. For single layer TiN coatings high dissolution rates
of iron were measured indicating corrosion of the underlying substrate. In multilayer systems this was not
observed which is, according to the authors, contributed to the lower numbers of coating defects in a multilayer
system. Based on this literature review, while TiN and CrN are commonly used for coatings in the PEMFC, the
PVD coatings have shown a worsened electrochemical behaviour under PEMWE conditions.
Coating deposition with thermal spraying for the BPP involves process related challenges. On the one hand,
the coating material is limited to commercially pure (CP) titanium with the affinity to oxidise easily during the
spraying process. The relevance of the process-related oxidation for the application is explained more in detail
in chapter 2.3 Coating Analysis. On the other hand, the BPP substrate should encompass a thickness of just
s ≤ 0.5 mm. Evidently, a high coating density is important as well in order to prevent the underlying substrate
from corrosion. Thermally sprayed coatings for the PEMWE have been studied firstly by Gago et al. [GAG+14]
using vacuum plasma spraying (VPS). By VPS, titanium coatings with an oxygen content of just ω ≤ 1% are
possible [LLH+87].
DVS 393 1

In order to reduce production costs, thermal spraying processes without vacuum technology are economically
more interesting. As a high coating density, a low oxide content as well as a low coating roughness for reduced
post-processing are targeted, Cold Gas Spraying (CGS), High Velocity Air-Fuel (HVAF), High Velocity
Oxy-Fuel (HVOF) are chosen for this study. The examination is focused on structural coating features and the
oxygen content as they allow an estimation of the coating performance in the PEMWE environment. The
following six aspects were considered during coating development in this study:
1. Substrate deformation during surface preparation
2. Substrate temperature and deformation during coating deposition
3. Process related oxidation of the deposited titanium
4. Coating thickness
5. Coating roughness
6. Coating density
2 Experimental Set-Up
For enhanced clarity, the following chapters are divided by substrate preparation and coating deposition. In
this chapter, materials and methods are explained.
2.1 Substrate Preparation
To promote the bonding mechanism of mechanical interlocking, sand or grid blasting is a common tool to
roughen the part surface. For this investigation, stainless steel sheets, X2CrNiMo17-12-2, of s = 0.5 mm
thickness are used representing unstructured BPPs. The substrates are prepared for coating with three
different methods: Grid blasting F24 at p = 4 bar manually (GB), grid blasting under same conditions but in a
fixture (GB-fix) and dry grinding with P80 sandpaper horizontally and vertically. The substrates are inspected
visually for deformation and tempering colours. Furthermore, the topography of the grid blasted and the grinded
surface are measured by confocal laser scanning microscopy (CLSM) VKX-200, Keyence Inc., Hokaido,
Japan.
2.2 Coating Deposition
The steel sheets are placed into a coating fixture with a coating area of A = 55 x 55 mm² as reported in
[BHB+23]. As introduced, CGS, HVAF and HVOF will be used for the deposition of titanium grade 4 powder,
Metco 4010C, Oerlikon Metco, Pfäffikon, Switzerland, with a fraction of F = -45 + 11 µm. The coating
parameters are given in Table 1.
Table 1. Coating parameters for CGS, HVAF and HVOF processes
Sulzer Metco,
Kinetiks 8000 (CGS)
Kermetico Inc.,
AK-07 (HVAF)
GTV Verschleißschutz
GmbH, K2 (HVOF)
Nozzle WC 2L 100K
Stand-Off distance in mm 30 200 180
Translational Speed in mm/s 200 1,000 1,000
Powder Feeding in 1/min 2.5 3.3 2 (20 g/min)
Carrier Gas N2 Ar + H2 Ar
Heating Medium 800 °C N2 0.8 MPa Propane 13 L/min Kerosene
Accelerating Gas ≈ 40 bar 0.9 MPa Comp.Air 990 L/min Oxygen
According to the coating parameters in the CGS-process, maximum gas pressure for Kinetiks 8000 is utilized
to process the less ductile and high-melting titanium. In this study, the same powder fraction is used for all
thermal spraying processes. Working with this comparably fine fraction of titanium powder, that is especially
suitable for CGS, in HVAF and HVOF is difficult as the powder is very reactive with nitrogen in hot
temperatures. For this reason, argon is used as carrier gas instead of nitrogen. In the previous study by the
authors [BHB+23], a coarser powder fraction of F = -90 + 45 µm was chosen for the HVAF-process, to minimise
oxidation. However, it was only successful to maintain the biggest particles as α-titanium. In consecutive
experiments, the fraction of F = -45 + 11 µm was tested with different carrier gases and stand-off distances for
the HVAF-process. The parameters in Table 1 are the results from these consecutive experiments. By the
chosen HVOF-coating parameters in Table 1, the stochiometric relation between kerosene and oxygen is
λ = 2.2, resulting in a relatively cold flame with a high particle velocity. Combining this with a relatively short
stand-off distance of dw = 180 mm, low process related oxidation and high coating density are intended.
2
DVS 393

2.3 Coating Analysis
The coated substrates are inspected visually for deformation and tempering colours. Coating thickness as well
as porosity are determined from scanning electron microscopy (SEM) images, Thermo Fisher Phenom XL G2,
Eindhoven, Netherlands. A low coating roughness is desirable as the surface area is more reduced to delay
electrochemical reactions. Furthermore, all cell components are stacked together to a cell system so
roughness peaks are potentially pressed into the other cell components causing an inhomogeneous
distribution of compression pressure. Therefore, coating roughness is determined by VKX 200 as well.
The process related oxidation is meaningful to the PEMWE application as the oxide TiO2 is a known dielectric.
Because of this dielectric, more energy is necessary to split water into hydrogen and oxygen by water
electrolysis. In order to examine process related oxidation of titanium qualitatively, x-ray diffraction (XRD) and
high resolution energy dispersive spectroscopy (EDS) was used in a previous study [BHB+23]. Yet, there are
important differences between these methods. The principle of XRD is to determine lattice parameters by
scattered x-ray radiation according to Bragg’s-Law. Therefore, primarily crystalline materials can be analysed.
Using this method, the identification of phase composition and its chemical compounds is possible. Due to the
high cooling rates in thermal spraying, not only crystalline but also amorphous phases exist in the coating
which are more difficult to quantify in XRD. Consequently, XRD provides information about e. g. crystalline
oxides but oxides in amorphous state remain undetected and cannot contribute to a reliable oxygen
determination. In EDS, x-ray emissions of excited secondary electrons are measured which are element
specific. These x-ray emissions vary on the atomic size of the tested element and there is a detection limit for
elements of an atomic number z ≤ 11. Nowadays lighter elements as oxygen, z = 8, can be examined by a
silicon drift detector which was discovered in the 1990s [SLL98]. According to Newbury and Ritchie [NR15],
however, EDS has gained the state of a “semi-quantitative” method for three reasons: Firstly, there is no
calibration of the measurement method, e. g. by standards, secondly, the yield of secondary electrons depends
on the sample properties and, thirdly, there is a low reliability regarding software based automatic peak
identification.
To analyse the surface chemistry, the oxidic content is examined by a different measurement method in this
study. In XPS, photoelectrons are emitted resulting in information about the binding energy of an electron in
the atomic orbital. The binding energy can be correlated to the oxidation state as the binding energy increases
with the oxidation state [SD20]. X-ray photoelectron spectroscopy (XPS) is conducted at the Fraunhofer CSP
in Halle, Germany, with support from the Fraunhofer IMWS, Halle, Germany. In order to characterise surface
properties, the depth profiling mode is used. In contrast to EDS and XRD where the profiling depth ranges
within the µm-scale [RKA+98, LT96], XPS characterises the top nanolayers [SD20].
3 Results and discussion
In this chapter, the qualitative and quantitative results are depicted to evaluate the coating structures. As aforementioned,
a highly dense and low oxide titanium coating is suitable for the application as BPP-coating.
Furthermore, a small coating thickness and a high surface quality are preferred.
3.1 Substrate Preparation
The investigation of different substrate preparation methods demonstrates that the chosen grid blasting
parameters are not suitable for the surface preparation of potential BPPs as heavy deformation is observed.
As Figure 1 shows, the deformation of the steel sheets could be reduced by the fixture but not fully prevented.
In addition to that, grid blasting residues are often locked in the roughened surface and can cause a diminished
quality of the high-end quality product.
Figure 1. Results from the substrate preparation with grid blasting, ellipses show deformed substrate areas
Consequently, homogenous manual dry grinding was tested which does not cause deformation of the
substrates. The surface topography after grinding is depicted in Figure 2. Evidently, by grid blasting, the surface
is ablated more heavily and in a more stochastic way. By dry grinding, the surface is primed more
systematically but with a smaller ablation depth. Because of negligible substrate deformation by dry grinding,
this type of substrate preparation is used onwards.
DVS 393 3

Figure 2. Hight profile of surface topographies after different substrate preparation, determined via CLSM Keyence VKX
200 with V = 200x and V = 500x for grinded and grid blasted surface respectively
3.2 Coating Deposition
At first, all coatings are inspected visually for coating colour, substrate deformation and steel tempering. These
qualitative results are depicted in Figure 3. Unmodified titanium is typified by a light grey colour. For CGS, a
greyish titanium coating can be deposited without substrate overheating. Due to the high kinetic particle impact,
deformation of the thin steel sheet by the peening effect is visible. The HVAF-coating is characterised by a
dark deposit. For this reason, the category “High” is given for the oxidation of titanium in Figure 3. Substrate
deformation is negligible in this case but overheating with blue tempering colours can be an issue. In HVOF,
because of the comparably short stand-off distance of dw = 180 mm, deformation and steel tempering are
visually observed.
Figure 3. Results of the visual inspection after coating deposition
To investigate the coating structure, SEM images of the three coatings are illustrated in Figure 4. The CGSand
HVOF-coating were embedded, grinded and polished metallographically. The HVAF-coating,
dc = 42 ± 9 µm, was cut with a diamond saw and was polished by ion beam at the Fraunhofer IMWS, Halle,
Germany. By this preparation technique, micro cracks are highlighted. Figure 5 shows coating roughness Rz,
porosity Φ and coating thickness dc. For the maximum profile height Rz, n = 5 measurements are evaluated
as a boxplot, Figure 5a). The boxplots depicts the median, the interquartile range in between the first and third
quartile as well as the upper and lower outliers. In Figure 5b), the average coating porosity and the average
coating thickness of n = 3 and n = 4 measurements are demonstrated. The error mark represents the standard
deviation.
Figure 4. Coating structures of investigated coatings, for CGS and HVOF by Thermo Fisher Phenom XL G2 at IOT and
for HVAF by Zeiss Sigma at Fraunhofer CSP
The coating structure of the HVAF-coating is comparably heterogenous as semi- and fully molten titanium
particles are deposited. Even though the HVAF-structure is heterogenous, the coating roughness, as shown
4
DVS 393

in Figure 5, is comparably low which can be ascribed to the complete flattening of the plasticised particles. The
fully molten particles are also strongly oxidised leading to a ceramic nature of the lamellae boundaries. As
such, the lamellae boundaries represent a weak spot for mechanical stresses.
At the particle impact, residual stresses are created by the thermal gradient, the high cooling rate and the
difference in coefficients of thermal expansion. The oxidic lamellae boundaries cannot resist against the
residual stress and form inter-lamellar cracks, red triangle, Figure 4. Trans-lamellar cracks, blue triangle,
Figure 4, are observed as well due to residual stresses by particle shrinking. Inter- and trans-lamellar cracks
are interconnected to a crack network. This crack network potentially allows electrolyte migration resulting in
part damage by corrosion. Because of the crack network, the measured porosity in Figure 5 is higher than for
the other coatings but constituted mayorly out of cracks.
Figure 5. a) Box plot of maximum of profile height R z from the CLSM-analysis, magnification V = 200x, b) Column
diagram showing average porosity and coating thickness from image analysis incl. standard deviation
The analysis of the HVOF-coating shows that the coating is built-up from broader lamellae with a thin outer
shell of oxides, Figure 4. After coating deposition, the metal sheet is bended by the peening effect leading to
tensile stresses in the coating. The tensile stresses result in inter-lamellar cracking alongside the oxidised
lamellae boundaries dominating this coating structure. The cracks propagate to the interface and cause partial
delamination there. Consequently, coating cohesion is affected negatively by the oxidised lamellae.
The CGS-coating exhibits a homogenous titanium deposit with low porosity of Φ ≈ 1%. Even though the
peening effect is also strongly present in the CGS-coating, the coating cohesion is higher in this type of coating.
Consequently, no lamellar cracking can be observed as the resistance against residual stresses is superior.
The coating roughness majorly contributes to the coating thickness as the roughness is comparably high, but
the coating thickness is relatively low. Regarding the requirements in a high coating density for the PEMWE
application, the CGS-coating shows the most favourable structural properties.
On a quantitative analysis by XPS, the surface area of the CGS-coating contains the lowest oxygen levels
while the HVAF-coating surface contains the highest, see Table 2, which confirms the results from the visual
impression. The XPS depth profiling indicates mainly TiO2 in the surface area of the HVAF-coating. According
to the XPS-measurements, the oxygen content is 10% lower on the surface of the HVOF-coating than of the
HVAF-coating.
Table 2. Results from XPS-measurements, conducted with Thermo Fisher XPS Nexa G2 by Fraunhofer CSP, Halle,
Germany, etching time t = 200 s, in a range of binding energy between -10 eV ≤ E ≤ 1,350 eV
ω(Ti)
in mass-%
ω(O)
in mass-%
ω(C)
in mass-%
ω(N)
in mass-%
Other
in mass-%
CGS-Coating 87.5 9.1 0.3 1.2 1.9
HVAF-Coating 59.6 32.8 1.6 1.4 4.6
HVOF-Coating 71.4 24.7 0.4 0.9 2.6
In the previous study [BHB+23], differences in the electrical behaviour were observed between CGS-coating
and HVAF-coating. Accordingly, current transport was more inhibited on the surface of the HVAF-coating than
of the CGS-coating. In addition, electrochemical passivation occurred faster on the surface of the HVAFcoating.
These observations can now be explained by the more oxidic character of the HVAF-coating surface
than of the CGS-coating surface identified by the XPS-measurements.
DVS 393 5

4 Summary
In conclusion, three high velocity thermal spraying technologies for titanium deposition are compared in this
study. For the BPP application in a PEMWE cell, the substrate is of only s = 0.5 mm thickness. For each
thermal spray technology tested, there is a different challenge.
To start with HVAF, the thin coating deposited shows potential in terms of coating thickness and coating
roughness. However, inter-lamellar and trans-lamellar cracking are observed being a potential driving force for
corrosion beneath the coating. In addition, the highest level of oxidation is measured for this coating. Further
coating development is necessary to stop the coating from cracking and to avoid extensive overheating.
By setting a high lambda λ in the HVOF-process, lower oxidising conditions in the hot gas stream of the
HVOF-process than in the investigated HVAF-process can be achieved. Yet, the deformation of the substrate
by the peening effect seems to be critical as inter-lamellar cracking and coating delamination are induced.
In contrast to HVOF and HVAF, the CGS-coating shows no cracking because of the superior coating cohesion.
Furthermore, the surface area representing the contacting area to other stack components exhibits the lowest
oxygen levels. The CGS titanium coating appears to be the most suitable coating for PEMWE application as
the coating exhibits a coating density of up to ρ = 99% resulting in promising corrosion properties. While the
overall coating properties are desirable, substrate deformation should not be underestimated and it will need
further engineering to control the deformation.
5 Outlook
In this study, coating deposition is conducted on a sample level. In the future, the CGS-process is going to be
scaled up by evaluating scale effects of larger coated metal sheets. Apart from the structural properties,
electrochemical, electrical and mechanical properties are going to be examined.
6 Acknowledgements
The H2Giga-project StacIE (03HY103B) is funded in the context of the competition of ideas
“Wasserstoffrepublik Deutschland” by German Federal Ministry of Education and Research. The authors like
to thank the project partner Fraunhofer IMWS, Halle, Germany for monitoring and conducting measurements
on behalf of the project StacIE.
6
DVS 393

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[GAG+14]
[LFM+15]
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[LT96]
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DVS 393 7

Plasma-spray deposition of Na3Zr2Si2PO12 electrolyte for high
performance all solid-state sodium-ion battery
Xiao-Chen Bu, Nan Chen, Xiao-Tao Luo, Chang-Jiu Li *; State Key Laboratory for Mechanical Behavior of
Materials, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an/China. Email address:
licj@mail.xjtu.edu.cn.
Abstract
All solid-state sodium-ion batteries (ASS-SIBs) have great potential for application to large-scale energy
storage devices due to their safety advantages by avoiding flammable organics and the abundance of sodium.
In this study, plasma spraying was used to deposit Na3Zr2Si2PO12 (NZSP) electrolyte for assembling
high performance ASS-SIBs. NZSP electrolyte layers were deposited at different spray conditions using
NZSP powders in different particle sizes. The factors influencing the microstructure and compositions of
NZSP layers were examined by characterizing the compositions of splat and cross-sectional microstructures
of the deposits. It was found that the preferential evaporation loss of Na and P elements occurs severely to
result in a large composition deviation from initial powders and spray particle size is key factor which dominates
their evaporation loss. The APS NZSP electrolytes present a dense microstructure with well bonded
splats which is attributed to low melting point of NZSP. The apparent porosity of the as-sprayed NZSPs was
lower than 3 %. The effect of annealing on the microstructure of APS NZSP was also investigated. The performance
of typical APS NZSP was also evaluated by assembling an ASS-SIB battery with APS NaxCoO2
(NCO), Na3Zr2Si2PO12 (NZSP) and Li4Ti5O12 (LTO) as cathode, electrolyte and anode, respectively. Results
showed that columnar-structured grains with a chemical inter-splat bonding were formed across the interfaces
between electrodes and electrolyte. There is no evidence of inter-diffusion of zirconium, cobalt and silicon
across the NCO/NZSP interface. With the preliminary battery, the solid electrolyte exhibited an ionic conductivity
of 1.21 × 10 -4 S cm -1 at 200 o C. The SIB can operate at 2.5 V with a capacity of 10.5 mA h g -1 at current
density of 37.4 μA cm -2 .
Keywords: Sodium-ion battery, NASICON electrolyte, plasma spray, capacity
1 Introduction
Recently sodium ion batteries (SIBs) have drawn great attention due to their great advantages: the abundance
of sodium (2.6 %, while lithium only accounts for 0.06 %), low mining costs and similar electrochemical
performance compared with lithium ion batteries [1-4]. The cost-effective manufacturing of SIBs with absolute
safety are beneficial for large-scale electrochemical energy storage system [2].
For traditional SIBs, liquid organic electrolyte are widely used, which still suffer from severe safety problems
such as liquid leakage and risk of fire [4, 5]. The solid-state Na-ion batteries are of great interest due to their
excellent safety advantage within a large operation temperature range and their potentially high energy densities
when compared to liquid counterparts [6, 7]. NASICON-type electrolytes with a general formula of
Na1+xZr2SixP3-xO12 (0≤x≤3) were first reported by Goodenough and attracted great attention for its high ionic
conductivity (10 -4 -10 -3 S/cm, RT) and chemical stability in air [4, 8]. Ran et al. found that the Sc and Ge codoping
of NZSP can stabilize the rhombohedral phase at RT and significantly boost the sodium ion transfer
[9]. For the synthesis of ceramic electrolyte, solid-state reaction is commonly used. However, the high
reacting temperature (>1200 o C) and long sintering duration (>10 h) may cause the element diffusion across
electrolyte/electrode interface [10-12]. Thus, it is difficult to make a compromise between the sintering temperature
of electrolyte and interface control of electrolyte/electrodes of ASSIBs.
Air plasma spraying (APS), as an efficient and economic coating technique, is theoretically capable of depositing
all kinds of ceramics which have a melting point [13]. For typical as-sprayed deposits of refractory ceramics,
more than 2/3 of the interface between splats are not bonded, which severely reduces the transportation
passage of ions and results in a much lower ionic conductivity along the thickness direction compared
with bulk material [13]. Yao et al. have reported that there exists a critical bonding temperature for certain
ceramic to achieve full bonding between adjacent splats during plasma spraying [14]. The critical bonding
temperature is proportional to the melting point of ceramic coating materials. With ceramic materials of a
melting point lower than 1450 o C, their critical bonding temperature is reduced to around or lower than the
normal temperatutre of 25 o C. This means that with such ceramic materials it becomes easy to deposit a
dense layer with well bonded splats. Fortunately, the NASICON-type electrolytes belong to such ceramic
materials. Besides the microstructure, the chemical composition is also crucial for the ionic conductivity of
NZSP. It has been proved that the extremely high temperature heating of plasma jet usually causes the preferential
evaporation of the constitute in complem ceramics with the high saturation vapor pressure and leads
to the deviation of chemical compositions from stoichiometric ratio of feedstock [15-17]. Zhang et al. reported
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that using sinter-crushed La0.8Sr0.2Ga0.8Mg0.2O3 (LSGM) electrolyte with a large particle size can significantly
reduce the Ga evaporation loss during plasma spraying of LSGM [17]. For NZSP, the sodium and phosphorus
elements prefer to evaporate due to their relatively high saturation vapor pressure. Yang et al. found that the
volatilization of Na and P elements in NZSP promoted the formation of ZrO2 content in NASICON matrix [18].
Therefore, it is important to understand the evolution behavior of NZSP particles during plasma spraying and its
influence on the chemical composition of the deposits.
In this work, APS was used to deposit NZSP electrolyte at different plasma arc power using Na3Zr2Si2PO12
powders. The effects of spray particle sizes, plasma arc power and annealing treatment on the microstructure
and chemical composition of APS NZSP deposits were systematically investigated. The effect of chemical
composition on the phase composition of NZSP deposit was examined. Moreover, a preliminary battery was
assembled to investigate the electrochemical performance of the APS-sprayed battery.
2 Experimental Procedures
2.1 Spray Material Synthesis
Na3Zr2Si2PO12(NZSP) was synthesized by the solid-state reaction, where the precursor powders Na2CO3, ZrO2,
SiO2, and (NH4)2HPO4 were ball-milled in anhydrous ethanol solvent in the above ratio for 8 h and calcined in
air at 800 o C for 12 h. Next, NZSP was ball-milled for 16 h to get fine powders. The resulting powders were
mechanically pressed into pellets with a compressive pressure of 200 MPa for 2 min. Finally, the pellets were
sintered at 1150 o C for 6 h to obtain the compact NZSP. The compact NZSPs were crushed to obtain spray
powders. Ultrasonic cleaning was used to remove the micro-sized powder (

2.2 Preparation of APS NZSP Deposits
Plasma spraying was carried out by a commercial plasma spray system (GP-80, Jiujiang, China). 430 stainless
steel buttons (15 mm in diameter and 1 mm in thickness) with surface grit-blasted were used as the
substrate to deposit NZSP electrolyte. The plasma jet was generated using a mixture of argon and hydrogen
gases under different spray parameters, which are shown in Table 1. During plasma spraying, the plasma
arc power was changed in three different levels of 32, 36 and 40 kW by altering arc current, while all other
spray parameters were kept constant. To ensure splat interface bonding, the NZSP deposits were prepared
at a deposition temperature of 300 °C. The isolated splats were also deposited on the polished substrate
surface at the deposition temperature of 300 °C at a rapid torch traverse speed of 1000 m/s to examine the
effect of spray particle size on the vaporization loss of Na and P elements. To investigate the effects of the
annealing on the electrical property of NZSP deposits, they were annealed in air at 600 °C, 800 °C and
1000 °C for 2 h, respectively.
Table 1. Plasma spray parameters.
Parameters
Value
Arc current (A) 550, 620, 690
Arc power (kW) 32, 36, 40
Primary gas (Ar) (SLPM) 45
Auxiliary gas (H2) (SLPM) 4
Spray distance (mm) 80
Torch traverse speed (mm/s) 450
2.3 Characterization of the Microstructure and Composition of the Deposits
The surface morphology and cross-sectional microstructure of the powders and deposits were observed
using scanning electron microscopy (SEM, MIRA 3 LMH, TESCAN, Czech). The apparent porosity and ZrO2
content of the deposits were estimated by digital image analyzing method according to the ISO/TR
26946:2011(E) Standard. In the cross-section images of the well-polished specimens, the pores are present
in the coating in a darker contrast than other areas, while the ZrO2 phase is presented in a whiter contrast.
After the binarization, the apparent porosity and ZrO2 content were obtained from the area ratios of pores
and ZrO2 to the total area of specimen. The elemental compositions of the samples were analyzed by the
energy dispersive spectrum (EDS). The crystal structure was characterized by X-ray diffraction (XRD, D8
ADVANCE) analysis with a step rate of 2° min -1 using Cu Kα radiation source in a 2θ range of 10-60°. The
profile and volume of the individual splats were measured using three-dimensional (3D) confocal laser scanning
microscopy (OLS5000, OLYMPUS, Japan).
2.4 Characterization of Electrochemical Performance of ASS-SIB
The functional layers of ASS-SIB battery were deposited in the order of NCO, NZSP and LTO on the
430 substrate using APS at a plasma arc power of 40 kW. Then, silver paste (82%, DAD-87, resistivity
< 5.0×10 −4 Ω·cm) was coated on the surface of both the LTO electrode and the substrate as current collectors.
The APS-sprayed battery was tested in the range of 0.5-2.5 V on the Zahner battery testing system
(Zennium X). The EIS was characterized using CS350 electrochemical workstation (Solartron SI 1260/1287
impedance analyzer) with an AC amplitude of 10 mV in frequency range from 0.1 Hz to 1MHz. The impedance
data were fitted by the ZView software (Scribner Associates Inc). The ionic conductivity (σ) is computed
using equation:
σ = l / (A × R) (2-1)
where l and A are the thickness of deposits and the area of silver current collector, respectively.
3 Result and Discussion
3.1 Effect of Spray Particle Size on the NZSP Splat Composition
The NZSP splats were deposited on the polished alumina substrates with a preheating temperature of
300 °C. Figure 2(a) shows the morphologies of the splats deposited at a plasma arc power of 40 kW. Most of
the splats exhibited a regular disk shape since the spray particles were fully molten before impinging on the
surface of substrate. A few of them exhibited a semi-molten state because of the poor heat transfer within
large particles. The single isolated splat seen from Figure 2(b) showed a smooth surface without cracks,
which may be attributed to the high deposition temperature which reduced the thermal mismatching stress
with substrate. Only small concaves in a black contrast were distributed on the surface of splats due to the
gas entrapment during spraying process.
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(a)
(b)
Figure 2. Morphologies of (a) NZSP splats deposited on the polished alumina substrate at plasma power of 40 kW, (b)
enlargement of the single isolated splat.
Figure 3 shows the effects of the particle diameter and plasma power on the molar ratio of Na and P to Zr for
isolated NZSP splats. The molar ratio of Na to Zr varied from 1.5 in the original powder to less than 0.8, while
that of P to Zr varied a similar tendency from 0.5 in original powder to less than 0.2. It is evident that with the
increase of the spray particle size, the molar ratios of both the Na/Zr and P/Zr increased. When the particle
size is less than 30 μm (stage I), the evaporation losses of both Na and P under a plasma arc power of
40 kW are more intensive than those of 32, 36 kW, which can be attributed to the more intense mass transfer
under higher plasma power. However, when the particle size was increased from 30 to 40 μm (stage II), the
evaporation loss tendency of Na and P was similar under different plasma powers. Moreover, no apparent
Na and P losses were observed when the particle size became larger than 40 μm (stage III). Therefore, it is
clear that the plasma power has significant impact to the evaporation loss of the spray particles having a
particle size less than 30 μm. Accordingly, the Na and P evaporation losses mainly occurs to the particles
less than 40 μm.
(a)
(b)
Figure 3. Effect of particle size on the atomic ratio of (a) Na and (b) P to Zr at different plasma powers.
3.2 Effect of Powder Particle Size on the Microstructure of NZSP Deposits
Figure 4 shows the cross-sectional microstructure of the deposits prepared by APS under plasma arc power
of 40 kW using feedstock powders with three different particle size ranges. The F-NZSP and M-NZSP deposits
exhibited dense microstructures. More pores are present in L-NZSP deposit than other deposits. With
EDS point analysis, the small block regions in a bright white contrast in Figure 4(a) are recognized as Zr and
O with an atomic ratio of 27.32 to 72.68. Assisted with the XRD patterns in Figure 6(a), it is evident that
these white regions are corresponded to ZrO2 phase, which may be evolved with the severe Na, P evaporation
loss during plasma spraying. The cross-sectional microstructure of the F-NZSP-40kW deposit after annealing
at 1000 o C is shown in Figure 4(d). The annealed deposit exhibits a similar dense microstructure.
The porosity of the annealed deposit slightly increased, which cound be attributed to the sintering of NZSP
deposit.
DVS 393 11

(a)
(b)
(c)
(d)
Figure 4. Cross-sectional microstructures of NZSP deposits prepared with (a) fine powder, (b) medium powder and (c)
large powder under the plasma arc power of 40 kW. (d) F-NZSP deposit annealed at 1000 o C.
The effect of plasma arc power on the porosity of the NZSP deposits were shown in Figure 5(a). The porosity
was significantly increased with the increase of the particle size from 30-50 μm to 60-75 μm. It was observed
that the dense NZSP deposit can be obtained with fine powders (30-50 μm) at plasma arc power of 40 kW
with a lowest apparent porosity of 0.8 %. From Figure 5(b), the ZrO2 content of F-NZSP deposits was higher
than other deposits and reached to 6.2-6.5 %. For M-NZSP and L-NZSP deposits, the ZrO2 content are below
2 %, which can be attributed to the less evaporation loss of Na and P in M-NZSP and L-NZSP deposits.
Moreover, it was recognized that the effect of plasma arc power on the porosity and ZrO2 content of the deposits
are not significant.
(a)
(b)
Figure 5. Effect of particle sizes on the apparent porosity (a) and ZrO2 content (b) of NZSP deposits.
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The XRD patterns of APS-sprayed NZSP deposits along with feedstock powders in different sizes are shown
in Figure 6(a). The original powder exhibited a crystal structure similar to the standard XRD pattern of monoclinic
NZSP (m-NZSP, PDF 84-1200), and the peaks of impure phase of monoclinic ZrO2 (m-ZrO2, PDF 83-
0941) were observed at 2θ = 28° and 31.5°. For the as-sprayed deposits, a new phase of tetragonal ZrO2 (t-
ZrO2, PDF 79-1767) was observed, which resulted in the obvious intensity increase of the major peak at 2θ
angle of ~30.4° and the appearance of a new peak at 2θ angle of 35.3°. The ZrO2 phase was formed due to
the evaporation loss of Na and P elements [18]. It was observed that the peak intensity of t-ZrO2 phase was
higher in F-NZSP than M-NZSP and L-NZSP deposits at 2θ of 35.3°. The appearance of t-ZrO2 can be attributed
to the rapid solidification process of plasma spraying, which preserved the high-temperature phase
to room temperature .
Figure 6(b) shows the XRD patterns of F-NZSP-40 deposits after annealing at different temperatures. When
the annealing temperature was lower than 800 °C, the XRD patterns of NZSP were similar to that of the assprayed
NZSP. From 800 °C to 1000 °C, the relative peak intensities at 2θ = 19.2° and 19.8° indicating major
phase of m-Na3Zr2Si2PO12 increased, while that of t-ZrO2 at 2θ = 35.3° decreased. These fact revealed
that the size distribution of feedstock powders and annealing temperature both have significant impact on the
crystal structure of plasma-spray NZSP deposits.
(a)
(b)
Figure 6. XRD patterns of (a) as-sprayed NZSP deposits with different feedstock powders at plasma power of 40 kW. (b)
F-NZSP-40 deposits annealed at different temperatures.
3.3 Performance of ASS-SIB Assembled by Plasma Spraying
A preliminary ASS-SIB, consisting of a NCO cathode, NZSP electrolyte and LTO anode, was assembled by
APS. All of the functional layers present dense microstructure and are well-bonded across the interfaces
between electrodes and electrolyte, as shown in Figure 7(a) and (c). From element mapping with EDS, there
was no evidence of interdiffusion of zirconium, cobalt and titanium across the interface between electrodes
and electrolyte.
DVS 393 13

(a)
(b)
(c)
(d)
Figure 7. (a) Cross-sectional SEM images of NCO-NZSP interface and EDS-mapping of (b) cobalt and zirconium. (c)
Images of LTO-NZSP interface and EDS-mapping of (d) titanium and zirconium.
Figure 8 shows the electrochemical performance of the cell operated at 200 o C. The evolution of the impedance
of the NaxCoO2/NZSP/LTO battery has been analyzed based on the impedance spectrum in Figure
8(a). From the fitted NZSP bulk resistance Rbulk ≈ 582.4 Ω, the ionic conductivity of the electrolyte can be
calculated to 1.01 × 10 -4 S/cm at 200 o C using equation (2-1). Figure 8(b) shows the galvanostatic cycling of
the cell between 0.5 and 2.5 V at 200 o C, which exhibited a capacity of 10.5 mA h g -1 for a current rate of
0.5C (37.4 μA cm -2 ).
(a)
(b)
Figure 8. (a) Impedance spectrum and (b) capacity of a plasma-sprayed NaxCoO2/NZSP/LTO ASS-SIB.
14
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4 Conclusions
The NZSP electrolytes were prepared by APS with feedstock powders in three different size ranges. The
effect of powder size, spray parameters and annealing were examined to clarify their impact on the microstructure
and chemical composition of the NZSP electrolytes. Moreover, a NaxCoO2/NZSP/LTO preliminary
battery was assembled by APS. The main conclusions can be drawn as follows.
1. The dense NZSP deposits with well-bonded splats were prepared by APS using NZSP sinter-crushed
powders. The porosity of the deposit could be reducded to less than 3.5 % with medium sized powders
in a size range of 50 - 60 μm.
2. The evaporation loss of Na and P occurred which resulted in the formation of ZrO2 phase during plasma
spraying. Results show that the evaporation loss can be alleviated when the particle size is larger than
40 μm.
3. The annealing has a limited impact on the microstructure of deposits. However, the high temperature
annealing (>800 o C) promotes the recovery of NASICON structure.
4. The preliminary ASS-SIB battery assembled with NZSP of an ionic conductivity of 1.01 × 10 -4 S/cm at
200 o C exhibited a capacity of 10.5 mA h g -1 at 0.5-2.5 V and a current density of 37.4 μA cm -2 .
Acknowledgments The present project is financially supported by the National Key Research and Development
Program of China (2021YFB4001400).
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Cold Atmospheric Plasma Metallization of Power Semiconductor
Devices with CuSn Pseudo-Alloys for Diffusion Soldering
Manuela Ockel, Aleyna Gökçen, Bettina Ottinger, Matthias Petersen, Christian Voigt, Jörg Franke
Cold atmospheric plasma spraying is used to produce thin coatings of copper and tin between 20-80 µm thickness
for use in diffusion soldering. This study presents an alternative process to apply composite solders
directly onto power electronic bare dies. The formation of intermetallic phases may be promoted by the homogeneous
distribution of the Cu and Sn particles as they are presented not in a layered structure but as a pseudo
alloy within the coating. The Cu and Sn powder is mixed in situ using two powder conveyors, enabling adjustable
mix ratios. The presented approach has been shown to produce a homogeneous particle distribution
within the coating. Furthermore, preliminary experiments indicate the feasibility of the technology for applications
in diffusion soldering.
1 Introduction
Efficient modules are crucial for the conversion of energy in electronic systems. The reliability of power modules
directly impacts functionality, cost effectiveness and lifetime. To realize the full potential of Wide-Band-
Gap semiconductors, the adjacent assembly and interconnection technologies need to have high-temperature
stability and must support efficient cooling. While silver sintering with nano-particles is an established hightemperature
die attach technology (> 300 °C), it uses high pressure and expensive materials to establish the
connection. For working at high temperatures (> 250 °C) gold-added solder pastes can be used. The interconnecting
materials are either provided as a paste or preform, or are deposited on one or both joined surfaces
for example by electroplating [1]. Diffusion soldering, Trans-Liquid-Phase Soldering (TLPS) or Solid Liquid
Inter-Diffusion technology (SLID) is used to create intermetallic phases (IMP) between a higher (e.g. copper)
and lower (e.g tin) melting material where die interconnection has a higher remelting temperature than the
material of the joining surfaces or the processing temperatures [2]. Cu atoms dissolve into molten Sn and form
Cu6Sn5 and Cu3Sn. Syed-Khaja [2] used the Cold Atmospheric Plasma Metallization (CAPM) to apply Cu
particles or Cu layers onto a printed Sn-based solder layer. In this study, we aim to eliminate the solder paste
printing by directly spraying lead free “dry-solder” in combination with Cu particles onto the substrate, using
CAPM. Thereby evaluating the feasibility of the technology to produce homogeneous copper tin composites
by combing two powders in situ. The resulting coating is a pseudo alloy where the two materials are mechanically
joined, yet the materials maintain their interfaces. The alloying is only promoted during diffusion soldering.
Additionally, the preforms introduced in Ottinger et. Al. [3] – a layered structure of Cu and Sn (see Figure 1, b)
– are combined with a direct Cu metallization of the backside of the bare die. The metallization in this paper is
similar to the front side metallization summarized in Ockel et. Al [4], where pure Cu coatings between
20-100 µm are applied via cold atmospheric plasma metallization to apply thermo-mechanical bond buffers to
enable Cu-based top-side interconnections, e.g. ultrasonic heavy Cu wire bonding.
The diffusion soldering process can be divided into four steps, as depicted in Figure 1. Firstly, the interlayer
materials have to be set up (1). Secondly, the materials are heated to a specified bonding temperature to
liquefy the low-melting layers (2) under mechanical pressure. Subsequently, the assembly is held at temperature
until the liquid has isothermally solidified due to interdiffusion (3). Lastly, the bond can be homogenized
by thermally treating the substrate several hours (4). The latter is dependent on the technical and economical
requirements of the bond. There are several approaches to set up the interlayer materials (Figure 1, a-c)).
Usually the materials are layered vertically and exist as a combined preform or solder and metallization combination.
The preform can have several layers of Cu and Sn. Horizontal approaches where Cu and Sn pastes
were applied side by side are also possible. However, a composite solder – a homogenous distribution of Cu
and Sn –is beneficial, since the formation of IMPs is dependent on the distances between the two materials
and can be minimized with this approach. The composite production can differ from using solder pastes with
Cu and Sn particles, coating Cu particles into a Sn-based paste or the direct deposition of Cu and Sn particles
via thermal spraying as introduced in this paper.
DVS 393 17

Figure 1. Process steps of TLPB for die attachment in power modules
The cold atmospheric plasma metallization has been optimized for non-destructive, low temperature deposition
of Cu particles onto bare dies [4, 5]. Braun et. Al. [6] previously utilized a similar setup to applying a tin coating
with CAPM as well. Comparable plasma spraying processes use an argon-based primary gas supplemented
with He, H2, or H2-H2. The arc current varies between 500 to 1000 A, powder feed rates are usually between
6-9 kg/h and particle velocities range from 600 to 2300 mm/s [7]. The adapted process in [5] is located at 300 A
arc current and can convey around 0,4 kg/h powder, suitable for thin coatings. The particle velocity could be
reduced to 200 m/s in comparison to 600-1000 m/s copper particles in cold spraying, which makes it suitable
for coating sensitive substrates. Cold spray is usually used for coatings with high electrical conductivity due to
their low oxide content since the particles are barely melted [8]. Besides recrystallisation, annealing under a
oxygenated atmosphere is used in [5, 9] to reduce the copper oxides which were formed during spraying in
ambient atmosphere. Tin melts at 232 °C whereas copper melts at 1083 °C, which makes the combination of
these materials in one process challenging, typically the process parameters are optimized for mono-material
applications.
2 Experimental Setup
The experiments were performed at the institutes Plasma Coating Unit (PCU) with ambient atmosphere (see
Figure 5, a). The setup comprises a heating stage which serves as a work piece carrier and is mounted onto
a six-axis articulated arm robot for trajectory flexibility (see Figure 5, a). The plasma torch is permanently
mounted in a stationary position for stability of the powder feeder rates (see Figure 5 b). The in situ mixing of
the powder takes place after the particles enter the plasma flame from opposite sides. As a substrate, siliconbased
thyristors (6.5 x 6.5 mm) with a silver backside-metallization are used. The coating geometry is defined
by a laser-cut shadow mask made of steel. The substrates are individually placed inside cavities and the mask
is mounted on top (see Figure 5, c). The carrier gas (argon) is set to 3 l/min each. The primary plasma gas is
argon (12 l/min) and is supplemented by an ArH2 secondary gas 2 l/min. An additional shroud gas comprised
of nitrogen (N2) with five percent hydrogen (H2) is used to minimize oxidation. The plasma is ionized inside a
rotationally symmetrical Cu laval nozzle and a tungsten cathode, ignited with the Plasmatron MC-60 with 200 A
and a 24 VAC ignition device. The combined powder feed rate is 6 g/min with argon as a carrier gas set to
6 l/min. For a standard Cu coating the deposition rate is around 20 µm per repetition of the coating as shown
in [9, 10]. The same Cu powder is used which has spherical particles with d50 = 11,86 µm and d90 = 20,21 µm.
Two different Sn powders were tested regarding their flowability. The first Sn powder has a particle size smaller
than 63 µm and is droplet shaped. The second Sn power plasmadust® is spherical as well. For the in situ
mixing of the powder each vibrational powder conveyor (Flowmotion) is equipped with one powder. The powders
are combined in different ratios according to Table 2. The Cu to Sn ratio is varied between 100 % Cu and
100 % Sn in twenty percent steps. The flow rate is determined before the coating by measuring the conveyed
powder weight with the precision scale LS 2200 from Precisa with a solution of 0,01 g for 15 min. Each powder
flow rate is determined individually in order to reach a combined deposition rate of 6 g/min. The particle temperature
and velocity are analysed with the Spraywatch 2S from Oseir which is mounted to the robot. Before
the coating of the bare dies a detailed analysis of the powders is carried out. To determine the fundamental
differences the powders were analysed via SEM (scanning electron microscopy). The first powder is spherical,
coated with a silicon layer according to an EDX analysis (see Figure 2) has a narrow particle size distribution
and therefore similar properties to the Cu powder in [4]. The second powder is irregularly, droplet-shaped, has
a smaller grain size and contains small particles, agglomerated with larger particles. The surface of the particles
is uncoated and significantly rougher as well (see Figure 3). Besides tin, a significant amount of phosphorus
was detected, however a silicon layer could not be measured.
18
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Figure 2. SEM (a-c) and EDX (d) analysis of spherical Sn powder plasmadust®
One prerequisite for defined homogeneous material distribution inside the coating is a coordinated powder
feeding rate for each Cu-Sn ratio. The flow rate for the Cu powder is for each ratio consistently lower than for
Sn. The flowing uniformity is similar for each powder. The flow rate for 20 % Sn is at the lowest limit of the
powder conveyor and could not be further reduced and is therefore higher than 20 % Cu powder. The feed
rate of the 20 % Sn series showed a consistent increase in the flow rate over time. This phenomenon was not
observed for other series. The powder flow rates are depicted in Figure 4.
Figure 3. SEM (a-c) and EDX (d) analysis of droplet-shaped Sn powder
The particle temperatures and velocities were measured for each Cu-Sn ratio in Figure 4. The temperature
measurement only provided results for experiments with Cu particles. The measurement for 100 % Sn did not
provide any results which indicates a temperature less than 1000 °C The temperature resolution of the camera
is limited to 1000 °C. TCu100% = 1933.5 °C for pure Cu, TCu80% = 1772.4 °C for 80 % Cu and for 20-60 % Cu ratio
the temperature is between 1553.3 to 1655.3 °C. The particle velocity is lower for higher Cu particle shares.
For 0-40 % Cu ratio the velocity is around 120 m/s. With increasing numbers Cu particles inside the plasma
flame the velocity decreases to 105 m/s. The gas flow rates were not modified.
Table 1. Flow rate parameters of Cu in powder conveyer one 1 and Sn in powder conveyor 2
Cu powder, conveyor 1 Sn powder, conveyor 2
Target
share
[%]
Determined
flow
rate [%]
Calculated
weight
[g/min]
Target
share
[%]
Determined
flow
rate [%]
Calculated
weight
[g/min]
100 30.0 6.0 0 0.0 0.0
80 24.0 4.8 20 1.0 1.2
60 20.0 3.6 40 2.0 2.4
40 14.5 2.4 60 5.5 3.6
20 5.5 1.2 80 8.0 4.8
0 0.0 0.0 100 11.0 6.0
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Figure 4. Powder flow rates (left) and particle temperatures and velocities (right) of different Cu and Sn ratios
The bare dies are placed into the cavities of the substrate carrier and fixed with a laser cut steel mask. The
substrates are preheated to 130 °C. Before the first coating a plasma cleaning with the same plasma parameters
but without particle injection is performed. The coating thickness is adjusted by repeating the process
between one to six times.
Table 2. Fixed and varied parameters of the experimental set-up of Cu-Sn
∑ Samples Cu ratio [%] Sn ratio [%] Fixed parameters
216 (6 samples
per parameter
combination)
100 0
Carrier gas flow rate [l/min] 3
80 20 Primary plasma gas flow rate [l/min] 12
CAPM
60 40 Secondary plasma gas flow rate [l/min] 2
40 60 Preheating [°C] 130
20 80
Temperature [°C] 180
Annealing
0 100 Duration [h] 7
The thermal treatment introduced is performed for half of the samples for each parameter combination. The
holding time is set to 7h at 180 °C under a N2H2 inert atmosphere in the Gero Carbolite GHA 12/300 tube
furnace with a maximum oxygen content of 15 ppm. The trans-liquid phase soldering (diffusion soldering) is
equivalent to the process presented in Ottinger et. Al. [3] and performed under a formic acid containing atmosphere.
The standard soldering profile parameters temperature and pressure are not adjusted during soldering
of different Cu-Sn ratios and for every substrate the same. Six bare dies are soldered onto a direct copper
bonded (DCB) substrate consisting of copper and an insulating ceramic. For microscopical analysis the Scanning
Electron Microscope Tescan Amber X with either an Everhart-Thornley detector (E-T) or LE BSE detector
for highlighted material contrasts at low landing energies was used. The layer thicknesses were analysed via
the laser scanning microscope Keyence VK-X3050. For the optical analysis a Leica DVM6 was used.
20
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Figure 5. Setup of Plasma Coating Unit for in situ mixing and coating of Cu and Sn powder
3 Results
After the adjustment of the inline parameters a total of 216 bare dies were coated with different parameters. In
order to avoid adhesion of the bare die during coating the mask geometry is smaller than the back side of the
chip. The continuous reuse of the shadow mask during one series results in uneven edges of the coating as
the mask edges are clogged with particles. This phenomenon is more pronounced for coatings with high Sn
content (see Figure 6). As the layer thickness increases clearly visible smolder is deposited at the edges. Due
to melting of deposited Sn on top of the mask solder splashes are visible on some of the bare dies. The edge
resolution is higher for coatings with high Cu content and the smolder deposition is moved from the coating
edges to the uncoated backside of the bare die. The varying Cu and Sn contents are directly visible after the
coating (see Figure 6). The color changes from dark red to silver in proportion to the Sn content. The comparatively
high thickness of the coating led to delamination of the coating with six repetitions for 80 and 100 % Cu
content. The high thermo-mechanical induced stress destroyed the chip during the cooling of the substrate,
not at the interface between pseudo-alloy the metallic contact of the semiconductor, but within the silicon.
A detailed surface analysis shows the homogeneous distribution of Cu and Sn. In Figure 7 the surface of the
coating with 20 % Cu and 80 % Sn is assessed in detail. With maximum magnification the scattered Cu particles
are visible in the optical image (Figure 7, b). The microscopical SEM analysis emphasizes the even distribution
of the splats (deformed particles). There are several unmolten Cu and Sn particles detectable at the
coatings surface (Figure 7, d). The Sn splats are flatter and more irregular deformed were as the Cu particles
form more even splats. Due to the high difference in the materials melting points the unequal behavior of the
particles was expected. To confirm the even distribution for all Cu-Sn ratios an EDX analysis was performed
for every combination. Besides Cu and Sn small contents of Oxygen and Carbon were detected (see Figure 8).
The measured Cu and Sn contents are in- or decreasing proportional to the set powder ratios, but the measurement
showed consistently lower contents of Cu or Sn as expected. Closest to the target Cu content is the
coating with 100 % Cu. 96 % of the surface are copper (see Figure 8). For the series with 80 % Cu only 70 %
Cu was measured and more Sn then expected (26 %). The results are similar for the series with 60 % Cu
content and 40 % Sn content. For 40 % Cu the measured outcome is 56 % Cu, for 20 % Cu more than 30 %
Cu content were detected. For 100 % Sn content only 88 % Sn were detected and 7 % Cu. This indicates
different deposition rates for the two materials.
Figure 6. Coated Bare Dies with 0-100 % Cu content, one and six coating repetitions in comparison
DVS 393 21

Figure 7. Surface analysis of coating with 20 % Cu – 80 % Sn; a) & b) optical image and c) & d) SEM analyses with LE
BSE detector for highlighted material contrast
Figure 8. Qualitative EDX analysis of surface coatings with 0 % - 100 % Cu content with detailed element distribution for
40 % Cu content and recorded energy spectrum
To validate the homogenous material distribution inside the coating metallographic cross-sections of the were
made. Without additional analysis the different Cu and Sn contents and their proportional deposition rate are
visible as well as their influence on the copper oxidation. Exemplary cross-sections for each Cu content are
depicted in Figure 9. Picture a) and b) also show a crack in the silicon due to the higher thermo-mechanical
stress with increased Cu contents. The coating was carried out in oxygen-containing atmosphere. The resulting
oxidation between the Cu layers is visible in picture a). With increasing Sn-content the copper oxidation is
reduced, which is also visible in Figure 6. Cross-section b) – d) shows a relatively homogeneous distribution
of Cu and Sn. Picture e) and f) have extremely low deposition rates. However, the thickness measurements
and solder experiments show improved deposition rates for other bare dies.
The quantification of Cu and Sn contents as well as pore distribution was done by measuring the area percentage
of each material. Surface irregularities were excluded. The measurements are carried out after each
process step. Before soldering, after soldering and after soldering with annealed substrates. Neither soldering
with annealing under hydrogen containing atmosphere nor soldering without annealing showed significant
changes in the distribution of Cu and Sn. The porosity increases significantly with lower Cu contents.
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Figure 9. Metallographic cross-sections of coatings with 100 % a), 80 % b), 60 % c), 40 % d), 20 % e) and 0 % Cu f).
The layer heights were measured via laser scanning microscopy. The overall average thickness for one coating
repetition is 29.01 µm and for six repetitions 75.51 µm. For 100 % Cu the average deposition rate is 16.52 µm,
which is roughly 10 µm lower than the presented deposition rates in Hensel et. Al. [5]. For 80 and 60 % copper
content the deposition rate is around 19 µm. For 40 and 20 % Cu ratio the deposition rate is significantly lower
with an average of 13.98 and 8.81 µm. A detailed look at each series shows a continuous decrease in the
deposition rate during the coating procedure. For high tin contents clogging of the plasma nozzle was an issue.
Insufficient cleaning leads to a reduction of the deposition rate. After cleaning the deposition rate for 100 % Sn
is at 18.18 µm. The laval nozzle in Figure 10 shows one sided clogging as only the powder feeder on the
opposite side conveys tin powder.
Figure 10. Layer heights per repetition for different Cu ratios and Sn clogged laval nozzle.
Half of the coated bare dies were annealed under hydrogen containing atmosphere. The pure copper coatings
show significant improvement of their electrical conductivity proven in [9]. After annealing the six chips are
placed onto a DCB for diffusion soldering. Between the pure copper coating and the DCBs preforms were
placed, each connection in this series was established successfully. The other connections were visually inspected
via radiography. Table 3. shows the number chips that showed initial adhesion after soldering. With
increasing Sn content, the number of successful connection increases. The annealed samples have a slightly
higher chance for a successful connection. For 100 % Sn every connection was successful. For higher coating
DVS 393 23

thicknesses the molten tin was squeezed out, since the solder stamps were not adjusted individually for each
bare die and formed Sn splashes.
Figure 11 shows the metallographic cross-sections of the diffusion solder connections without additional preforms.
Figure a) to c) show a gap between the DCB copper and the plasma sprayed coating. The quality of a
successful connection could not be assessed via radiography. The cross-section shows insufficient adhesion
for several connections which firstly had been classified as sufficient. A point connection distributed across the
interface is likely. Only the coatings with high Sn content showed an almost continuous connection.
Table 3. Successful connections (initial adhesion) after diffusion soldering dependent on the Cu content.
Cu
[%]
Sn
[%]
Successful connections
without annealing
Successful connections
with annealing
80 20 0 2
60 40 1 2
40 60 1 3
20 80 5 4
00 100 6 6
The addition of preforms improved the bare die adhesion significantly. With either annealed or not annealed
copper coatings a connection could be established during soldering. The tin at the interface to the plasma
sprayed coating flowed into the irregular surface. Whether an intermetallic phase has been formed at the
interface has yet to be proven via SEM and Raman-Spectroscopy. The difference between annealed and not
annealed substrates is clearly visible in Figure 12. Although diffusion soldering has been carried out under
formic acid containing atmosphere the copper oxides could not be reduced significantly. Only the hydrogen
reduction showed significant reduction of the copper oxides.
Figure 11. Metallographic cross-sections of solder connections without additional preforms
24
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Figure 12. Metallographic cross-sections of solder connections with additional preforms without (left) and with (right) annealing
under hydrogen containing atmosphere
4 Discussion
The flow rates analysis showed the possibility to convey low powder rates for producing thin coatings. However
spherical tin particles need to be used, since droplet-shaped particles could not be conveyed at all due to
significant agglomerations before the powder could be. The additional silicon coating could improve flow rate
stability and was not detected on the other powder. The conveyed power mass is dependent on the particle
size, which is why always more tin than copper has been conveyed. However, the significantly lower melting
temperature of tin lead to reduced deposition rates of Sn. The parameter and powder for Sn need to be optimized
independently from Cu spraying. The clogging of the plasma nozzle occurred after only a few coatings
were applied. This will need to be monitored closely since it reduces the deposition rate. The oxidization during
spraying in oxygenated atmosphere needs to be minimized during or after the process. The thermal annealing
under N2H2-atmosphere did not show any improvement regarding the oxidation. To inhibit diffusion before the
soldering process the temperature was reduced to 130 °C to prevent Sn melting but did lead to a reduced
reduction process of the oxides which usually occurs at temperatures above 350 °C. The Cu and Sn particles
are horizontally and vertically homogeneously distributed which enables flexible adjustment of Cu-Sn ratios
without mixing the particles before the power conveyors. The diffusion soldering worked for high Sn-contents
(80 % and 100 % Sn), with increasing Cu contents the die attach did not work. The temperature and pressure
during soldering has not been adjusted to account for different Cu contents. With less liquid tin the solid-liquid
diffusion area, which is responsible the primary connection, is reduced drastically. With higher Cu contents the
direct interface contacts between DCB and pseudo-alloy are larger in area with Cu and therefore solid-liquid
diffusion is reduced. To ensure adhesion at the interface between DCB and coating an additional Sn layer
could improve the adhesion. The soldering with preforms showed even distribution of Sn into the rough surface
of the Cu coating. The soldering with formic acid was not able to reduce the copper oxides. Prior annealing at
higher temperature however, reduced the oxides completely. For the analysis of IMP-formation further analysis
has to be conducted. An IMP formation at the particle’s interfaces and its influence on the soldering process
cannot be ruled out. If IMPs formed during soldering at the particle’s interfaces and the DCB-coating interface
has to be proven as well.
5 Conclusion
The study proved that a direct coating of bare dies with Sn or Cu/Sn combinations via the cold atmospheric
plasma spray process is possible without destroying the bare die. The distribution of Cu and Sn particles is
uniform inside the coating. Even with oxygen residues diffusion soldering with high Sn contents was possible
which shows potential of the technology. The diffusion soldering parameters need to be adjusted to the specific
coating properties. An additional homogenization of the joint is an additional option as well. The inline process
monitoring for Sn must be adjusted with particle monitoring for temperatures lower than 1000 °C. The efficiency
and deposition rate needs to be analyzed and optimized in further research, since [10] showed, that the effective
deposition of Cu particles is only at 20 % of the total power consumption. The deposition efficiency for tin
is expected even lower, since the low melting point leads to evaporation of the material.
6 Acknowledgements
The scanning electron microscope which was used for the SEM and EDS analysis is funded by the Deutsche
Forschungsgemeinschaft (DFG, German Research Foundation) – 442921285.
DVS 393 25

Literaturverzeichnis
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ISBN 979-8-3503-3484-5
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LER, C. GOTH und J. FRANKE. Reliability of lead-free solders for die attach in automotive power
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S. 409-413. ISBN 979-8-3503-9885-4
[4] OCKEL, M., A. HENSEL, S. STEGMEIER und J. FRANKE. Plasma Powder Copper Coating on silicon
substrates for copper wire bonds in comparison to state-of-the-art top-side interconnection technologies.
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417-427
26
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Comparative Studies of SUS316L Layer Deposited by Conventional
Laser Cladding and Extreme High Speed Laser Cladding
T. Izumi(Hyogo, Japan), A. Yano(Hyogo, Japan), and M. Arai(Tokyo, Japan)
Extreme High -Speed Laser Cladding (EHLA) is a new process category of laser cladding. In this study, EH-
LA layer was characterized by comparing with conventional laser cladding (LC) layer. Basic SUS316L layers,
as well as WC-reinforced SUS316L layers, were formed on SUS304 substrates using both LC and EHLA
processes. The macroscopic morphology, microstructure, microhardness, wear resistance, and residual
stress of the four types of layers were evaluated. As a result, EHLA layers exhibited slightly higher microhardness
and less wear loss than that of LC layers, despite the presence of more micropores. This can be
due to their finer dendritic structures. Furthermore, residual stress of EHLA layer was lower than that of LC
layer due to those micropores. Additionally, EHLA can add up to 45 wt.% WC into SUS316L layer without
crack formation, resulting in higher wear resistance than that of LC where crack formation occurred at
25 wt.% WC. This enhanced crack resistance in EHLA is believed to be due to the less heat input during
deposition.
1 Introduction
Extreme High-Speed Laser Cladding (EHLA) has been proposed as a new process with high deposition
efficiency [1]. Figure 1 shows a schematic diagram of the principles of conventional Laser Cladding (LC) and
the EHLA process. EHLA enables high-speed deposition by reducing the laser spot size to approximately 1
mm in diameter, thus increasing energy density. Powders are also focused on this small spot and melted
before reaching the substrate surface. Simultaneously, the residual laser energy creates a shallow melt pool
on the substrate surface, enhancing metallurgical bonding. EHLA operates at a velocity of 15–200 m/min and
a deposition efficiency of 0.3–3.2 m²/h, which is 10–100 times greater than that of LC. This high-speed process
significantly reduces heat input to the substrate, thereby minimizing thermal distortion and dilution. These
technical advantages position EHLA as a promising technology for surface treatment applications across
various industrial fields. However, there is limited research investigating the characteristics of EHLA layers
due to its relatively recent introduction, necessitating in-depth investigation. In particular, there are even fewer
reports on EHLA layers reinforced with carbide ceramic powders which are often used to improve the
wear resistance and hardness of the deposition layer [2]. In this study, EHLA layers were characterized in
comparison with LC layers. The basic SUS316L layers, as well as WC-reinforced SUS316L layers, were
formed on SUS304 substrates using both LC and EHLA processes. The macroscopic morphology,
microstructure, microhardness, wear resistance, and residual stress of the four types of layers were evaluated.
2 Experimental procedures
A 10kW diode laser coupled with a conventional lathe and a precision six-axis robot was used to both the
EHLA and LC processes. SUS316L powders were deposited on a SUS304 cylinder whose dimensions are
φ30 × 200 mm. The chemical composition of the powders for LC and EHLA was almost the same, but the
range of particle sizes was different. The powder diameters for LC and EHLA were 53-150 µm and
20-53 µm, respectively.
DVS 393 27