ICMCTF 2012! - CD-Lab Application Oriented Coating Development

Furthermore, the silane coupling agent can solidify itself through hydrolysis
and condensation processes which can be an easy and fast way to modify
the surface of PP.
According to the results of the gas permeation test, it was found that the
polymers modified with a variety of silane coupling agents prior to DLC
coating showed high gas barrier properties. Especially the silane coupling
agents with an amino group showed very low oxygen transmission rate,
which was comparable to that of DLC-coated PET with extremely high gas
barrier property. The barrier improved factor (BIF) became approximately
300 times higher than that of the untreated PP. This method can be
applicable to several types of polymers including polyethylene (PE) .
It is concluded that the surface modification using silane coupling agent is
expected to be a great method to produce high barrier DLC on several
polymers, which would expand the industrial application of the DLC-coated
polymers.
3:30pm G5-1-6 Cathodic Arc Plasma Treatment for Surface Alloying
and Modification, M. Urgen (urgen@itu.edu.tr), Istanbul Technical
University, Turkey INVITED
In this talk, the motivation and principles behind “Cathodic Arc Plasma
Treatment” (CAPT), a method involving application of high and low bias
voltages to the substrate in a cyclic-pulsing manner during cathodic arc
evaporation process will be introduced. This method differs from other
relevant techniques since it does not aim to modify coating structure or
surfaces with ion bombardment or ion implantation. It aims to benefit from
the diffusion enhancing atomic - bulk heating effects induced through
substrate - ion collisions during high bias voltage applications for alloying
the substrate material with the condensing cathode material. The role of
substrate temperature, magnitude, duration and type of high bias voltage
and cathode current on surface alloying and intermetallic formation will be
discussed based on studies conducted on binary Al-Cu 1 Cu-Al 2, 3 , and Co-
Cr 4 and Al-Fe-Cu 1 ternary systems.
References:
Corlu, B., Ürgen, M. (2009). Surf. Coat. Tech., 204(6-7), 872-877
Corlu, B., Urgen, M. (2010) Surf. Coat. Tech. 205(2), 540-544.
Arpat E., Urgen M., Intermetallics 19 (2011) 1817-1822
Akkaya, S.S, Sireli, E., Alkan B., Urgen M., Surf. Coat. Tech.,
doi:10.1016/j.surfcoat.2011.09.046
4:10pm G5-1-8 Microstructure and tribological properties of laser
textued PVD coatings on tool materials, M. Adamiak
(marcin.adamiak@polsl.pl), Silesian University of Technology, Poland
Optimisation of manufacturing processes in mechanical engineering which
involve high surface loads, machining speed or high working temperatures
is today under intensive investigation worldwide. Recent advances in laser
technology open new roads for modification of surface tribological
properties, by generation of the solid lubricant reservoirs in hard coatings.
The application of TiN, TiAlN and Ti(C,N) PVD coatings deposition and
their laser surface texturing to permit storage of solid lubricants using the
dimple reservoir concept on several tool steels was studied as possibly
technology to improve the work life of tools made from them. Simulation of
selected tribo-systems, microstructure and mechanical properties
examination were carried out. The results show that significant increase of
wear life (cost saving) can be achieved. It was discovered that the laser
texturing of PVD coatings with optimum area for dimple reservoirs when
combined with a low cost solid lubricant application, is a useful and cost
effective tool for wear and friction control.
4:30pm G5-1-11 Evaluation of Electochemical Boriding of Inconel
alloys, V. Sista (vsista@anl.gov), Argonne National Laboratory, US, O.
Kahvecioglu, Istanbul Technical University, Turkey, G. Kartal, Technical
University of Istanbul, Turkey, Q.Z. Zeng, Xian Jiaotong University, China,
O.L. Eryilmaz, A. Erdemir, Argonne National Laboratory, US, S. Timur,
Istanbul Technical University, Turkey
Inconel alloys are very common nickel based super-alloys which are used
extensively for a variety of high-temperature and aggressive environment
applications such as metal seat ball valves, high temperature fasteners,
nuclear reactors etc. They are extremely resistant to high temperature
corrosion and boriding them would further enhance their corrosion
resistance and improve their tribological properties. In this study, we
performed electrochemical molten salt boriding which was carried out in a
borax bath at 950°C for just 15 minutes to produce a very homogeneous,
boride layer of 81µm in thickness. Different boride phases were identified
by X-ray diffraction and the morphology of the borided surfaces was
characterized by both optical and scanning electron microscopy (SEM).
Microhardness measurements for different layers of nickel borides were
measured and found to be in the range of 1500-1900 HV. Pin on disk wear
tests were performed under dry and lubricated conditions and much superior
wear performance of borided surfaces with a wear depth of 1-1.5 µm was
confirmed compared to the base Inconel alloys with a wear depth of 13-15
µm.. The aim of this study is to show that electrochemical boriding is
applicable to Inconel alloys and this method can be considered as an
alternative way of producing hard boride layers on Inconel and hence make
them more resistant to mechanical and environmental degradations.
4:50pm G5-1-12 Electrochemical Boriding of Molybdenum, O.
Kahvecioglu (kahveciog3@itu.edu.tr), Istanbul Technical University,
Turkey, V. Sista, O.L. Eryilmaz, A. Erdemir, Argonne National Laboratory,
US, S. Timur, Istanbul Technical University, Turkey
In this study, we explored the possibility of electrochemical boriding of
molybdenum (99.5% purity) plates in a molten borax electrolyte.
Electrochemical boriding was performed at 950-1000 °C for 2-3 h and at a
current density of 0.5 A/cm 2 . The boride layers formed on the test samples
were 40 to 48 μm thick depending on process temperature and duration. It
was found that two distinct boride phases (namely Mo2B5 and MoB) could
be obtained on molybdenum substrate. The mechanical, structural, and
chemical characterization of the boride layers was carried out using a
Vickers micro-hardness test machine, optical and scanning electron
microscopes, and a thin film x-ray diffractometer. The hardness of boride
layer was in the range from 1800–2700 ± 50 HV depending on the load and
the region from which the hardness measurements were taken. Crosssectional
micro-hardness tests showed that the boride layers were well
adhered within each other whereas Rockwell C adhesion test applied on top
of surface showed delamination. Structurally, the boride layers were very
homogenous and uniformly thick across the borided surface area.
5:10pm G5-1-13 Mechanical and Microstructural Characterization of
Nitrided AISI 4140 steel with Electroless NiP Coating, R. Torres
(ricardo.torres@pucpr.br), P. Soares, Universidade Católica do Paraná,
Brazil, M. Soares, IFSC, R.M. Souza, Mechanical Engineering Department,
Universidade de São Paulo, Brazil, P. Souza, Universidade Católica do
Paraná, Brazil, C. Lepiesnski, UFPR, Brazil
Electroless nickel (NiP) is widely applied in the off shore industry, due to
its superior corrosion behavior in environments rich in H2S and CO2. The
Electroless nickel is deposited onto steel substrates by a self-catalytic
process, which involves temperatures and time to create a layer with
thickness around 75 µm. The major drawback of electroless nickel is the
post treatment process, which results in softening of the steel substrate due
to exposition to high temperatures for long periods of time. This post
treatment process creates a diffusion layer between the steel and NiP. The
aim of this ongoing research is to investigate the effect of introducing a
nitrided layer prior to deposition of NiP layer, as an attempt to avoid the
softening of the steel substrate in areas close to the NiP coating. To this end,
NiP coatings were obtained over nitrided and non-nitrided steel substrates.
The nitriding process was conducted in plasma environment using 75%
nitrogen and 25% of hydrogen. The nitriding temperature and time were
480oC and 6 hours, respectively. The NIP deposition temperature was
90oC, the deposition times were 2 or 4 hours, to produce two different
coating thicknesses. The post treatment process temperature and time were
610oC and 12 hours, respectively. Specimens were analyzed in terms of
coating thickness, structure and hardness. It has been found that the nitrided
layer reduces the NiP deposition rate, even though the diffusion layer
thickness and spatial distribution of P and Ni remains practically unchanged
in comparison with the non-nitrided specimens. During the post treatment
procedure, the nitrided layer avoided the softening of the substrate area in
contact with NiP.
49 Tuesday Afternoon, April 24, 2012