ICMCTF 2012! - CD-Lab Application Oriented Coating Development

GP-10 An experimental study on a large area multi-electrode
discharge in the fabrication of microcrystalline thin film solar cell, H.
Seo (shseo69@kaist.ac.kr), S. Lee, Y. Chang, Korea Advanced Institute of
Science and Technology, Republic of Korea
Recently, there have been many research for higher deposition rate (DR)
and good uniformity of μc-Si:H film in large-area discharge. Two factors
should be the most important issues in the fabrication of the thin film solar
cell. In order to solve these issues, several dicahrge conditions, including
large area electrode (more than 1.1 mx1.3 m), higher pressure (more than 1
Torr), and very high-frequency RF power (more than 40 MHz), have
attracted. But, in the case of large-area capacitive discharges (CCP) driven
at high frequencies, the effect caused by the standing wave should be
important limitation. Furthermore, the ion damage on the thin film layer by
the high sheath voltage can cause the defects, which degrade the film
quality.
Here, we will propose new CCP electrode concept, which consists of a
series of electrodes and grounds arranged by turns, and provide the
processing results. The high DR (1 nm/s), the controllable crystallinity
(~70%), and the relatively good uniformity can be obtained at the high
frequency of 40 MHz in the large-area discharge (280 mm x 540 mm). And,
we will show the TEM images of the μc-Si:H films at the various conditions
of μc-Si:H films, and discuss the crystal formation compared to the case of
VHF CCP. Finally, we will discuss the issues in expanding the multielectrode
to the 8G class large-area plasma processing (2.2 mx2.4 m) and in
improving the process efficiency.
GP-11 Advanced PVD coatings in a combination with a new
intermetallic substrate for hobs - A major step forward in productivity,
P. Immich (pimmich@lmt-fette.com), U. Kretzschmann, U. Schunk, R.
Fischer, LMT Fette Werkzeugtechnik, Germany
The ever increasing demand for higher productivity in manufacturing gears
requires advanced hard coatings and new substrate materials. Up to now in
this field of gear manufacturing two different substrate materials are availed
for single-piece hobs: powder metallurgy high-speed steel (PM-HSS) and
cemented carbide. Today PM-HSS has a market share around 70% offering
limited cutting speeds for wet and dry conditions on labile machine
conditions. On the other hand cemented carbide offers from the technical
point of view strong performance related features like high cutting speeds
up to 400 m/s on stable machine conditions. .
But due to the fact, that hobs have a typical life cycle time of 10-15
recondition cycles– hobs are often demounted – packed and shipped –
decoated- regrinded and coated again- could cause small handling or
production damages that result in a shorter tool life time and less reliability
of the production process. Additionally using cemented carbide hobs
required often new hob machines with stable machine conditions.
To fill this gap, a new generation of substrate material was developed based
on intermetallic phases. This cutting material offers compared to
conventional PM-HSS higher hot hardness and as result from this higher
cutting speeds. In fact today hobs are coated and e.g. dry gear cutting is
only possible with coated tools due to the prevention of chip welding.
Today hob coatings that are available on the commercial market mainly
based on TiAlN system applied by AIP and Sputter PVD processes.
Since the last years a strong development towards higher wear resistance
coatings by adding e.g. silicon to the TiAlN-system can be observed. But
these systems are limited. Now there is a significant switch in the market
towards the system Cr-Al-N offering higher oxidation resistance and higher
wear resistance. In this regard different state of the art coatings are applied
on this new hob material and tested in laboratory scale and industrial filed
tests. Especially a new developed AlCrN multilayer coating offers a higher
wear resistance compared to state of the art coatings. As a result of these
investigations it is possible to increase cutting speeds up to 50% compared
to conventional coated PM-HSS hobs
GP-12 Adhesive-free gas adsorption joining of cycloolefin polymer film
and glass sheet, Y. Taga (y-taga@isc.chubu.ac.jp), Thin film research
Center, Chubu University, Japan
Attempt has been made to join glass and cycloolefin polymer (COP) film by
gas adsorption method at low temperature. Gas coadsorption of water vapor
in air atmosphere and silane coupling agent (SCA) gasses was carried out
on both surfaces after sophisticated plasma treatment. SCA of
glycidoxypropyltrimethoxysilane (GPS) was adsorbed on glass sheet and
aminopropyltrimethoxysilane (APS) on COP. Thicknesses of glass sheet
and COP film were both 100μm. Joining was carried out by annealing at
130� for 10 min after lamination. A necessary condition for joining of
COP and glass is at first to make the contact surfaces clean, where surface
cleanliness was evaluated by contact angle of water droplet. Surface
functional group of O-H can be seen on glass after corona plasma treatment.
On the other hand, XPS spectra of C1s from COP surface after plasma
Thursday Afternoon Poster Sessions 124
treatment revealed the existence of complex functional group of O-H, CO,
C=O, COO and CO3 . Joining force was found to be of more than 10MP
corresponding to almost equal to COP bulk tensile strength. Thickness of
joining layer was evaluated by XPS and found to be 2-5 nm. In addition,
durability of strength thus joined remained unchanged over 2000 hrs even
after exposure to the conditions of 60 � and 95% RH. Joining mechanism
can be explained in terms of epoxy reaction and amino reaction to form
covalent bonding such as O-Si-O and O-Si-C. In conclusion, adhesive-free
gas adsorption joining of glass and COP was carried out and established
strong adhesion and durability at low temperature under ultimate joining
thickness of 2-5 nm.
GP-13 Silicon oxide permeation barrier coating of PET in microwave
plasmas with arbitrary substrate bias, S. Steves (steves@aept.rub.de),
Electrical Engineering and Plasma Technology, Ruhr-Universität Bochum,
Germany, B. Oezkaya, Technical and Macromolecular Chemistry,
University of Paderborn, Germany, M. Rudolph, M. Deilmann, Electrical
Engineering and Plasma Technology, Ruhr-Universität Bochum, Germany,
C.N. Liu, Technical and Macromolecular Chemistry, University of
Paderborn, Germany, N. Bibinov, Electrical Engineering and Plasma
Technology, Ruhr-Universität Bochum, Germany, O. Ozcan, G.
Grundmeier, Technical and Macromolecular Chemistry, University of
Paderborn, Germany, P. Awakowicz, Electrical Engineering and Plasma
Technology, Ruhr-Universität Bochum, Germany
Plastics such as PET offer poor barrier properties against gas permeation.
For applications of PET in food packaging the shelf live is reduced
compared to glass or metal containers. Barrier performance is enhanced by
depositing a transparent plasma polymerized silicon oxide (SiOx) coating on
the inner surface of the PET bottle. A permeation barrier coating of the
inner surface of PET bottles and PET foils is developed by means of a
microwave driven low pressure plasma reactor based on a modified
Plasmaline antenna. A substrate bias with arbitrary waveforms is applied.
Thus, the substrate electrode voltage is feedback controlled using fast
Fourier transformation. The influence of a substrate bias leading to variable
ion energy distributions is investigated with respect to the characteristics of
plasma and coating.
Properties of coating are correlated with plasma characteristics. Barrier
properties are determined concerning oxygen permeation. The composition
of the coatings regarding carbon and hydrogen content is analyzed by
means of Fourier transform infrared spectroscopy (FTIR) and x-ray
photoelectron spectroscopy (XPS). Good oxygen barriers are observed as
carbon content in the film is reduced. Atomic oxygen etching of the coated
substrate visualizes coating defects responsible for a residual permeation.
Crack formation mechanisms are studied in-situ by means of atomic force
microscopy (AFM) using an AFM-stage to apply a desired strain. In
addition, the evaluation of water up-take in barrier films was performed.
The results show how process parameters such as gas composition and
substrate bias have an impact on properties of permeation barrier coatings.
The authors gratefully acknowledge the support provided by the Deutsche
Forschungsgemeinschaft (DFG) within the framework of SFB-TR 87, the
Ruhr-University Research School, Aurion Anlagentechnik Seligenstadt and
the Center for Plasma Science and Technology – CPST (Ruhr-Universität
Bochum).
GP-14 Fluidized Bed Machining (FBM) of thermally sprayed cobaltchromium
and chromium oxide coatings, M. Barletta
(barletta@ing.uniroma2.it), S. Guarino, V. Tagliaferri, F. Trovalusci,
Università degli Studi di Roma Tor Vergata, Italy
In the present paper, Fluidized Bed Machining (FBM) of thermally sprayed
coatings is proposed. In particular, aluminium cylindrical components
coated by High Velocity Oxy Fuel (HVOF) with Stellite 6 (cobaltchromium
alloy) and by Atmospheric Plasma Spraying (APS) with
chromium oxide were exposed to the impact of suspended abrasives, while
rotating at high speed within the fluidization column. The interaction
between Al2O3 abrasive media and surfaces of the thermally sprayed
coatings was studied, identifying the effect of the main process parameters,
such as machining time, abrasive mesh size and rotational speed. The
change in surface morphology as a function of the process parameters was
evaluated by Field Emission Gun – Scanning Electron Microscopy (FEG-
SEM) and contact gauge prof ilometry. The change in the size of the
machined parts was measured by Coordinate Measuring Machine (CMM).
The experimental findings emphasize an improvement in the finishing as
well as in the dimensional accuracy of the processed surfaces was achieved
whatever the setting of the operational parameters, showing FBM as a very
promising technique in the reprocessing of thermally sprayed coatings.
Key words: Fluidized Bed; Abrasive; Grinding; Thermally Sprayed
Coatings; Morphology; Dimensional Tolerance.