ICMCTF 2012! - CD-Lab Application Oriented Coating Development

of AISI 52100 steels by developing the powder-pack boriding method. The
treatment was carried out at a temperature of 1223 K with 1 h of exposure.
The boriding of AISI 52100 steels results in the formation of a superficial
flat front growth of FeB/Fe2B layers with a total layer thickness of 72
microns. In addition, the hardness at the surface of borided steels was 1900
HV.
The four-ball lubricant tests were performed in the borided samples (with a
surface roughness of 0.043 microns) and unborided steels with a surface
roughness of 0.025 microns considering dry and lubricant conditions. The
wear resistance of borided and unborided steels in the dry condition was
estimated by three different loads of 49, 98 and 147 N with a constant speed
and time test of 1200 rpm and 150 s, respectively. For the case of the
lubricated condition, the borided and non-borided steels were exposed to
applied loads of 147 and 392 N according to the ASTM D4172 standard
using commercial SAE 15W40 engine oil. For all cases, the friction
coefficients of borided and unborided steels were monitoring by a full
bridge load cell, and the temperature was sensed through a thermocouple in
real time during the four-ball lubricant test. The wear scar diameter and the
wear scar surfaces of the AISI 52100 borided and non-borided steels in both
experimental conditions were measured using an optical microscope and
scanning electron microscopy (SEM) to understand the wear mechanisms
involved.
Considering the dry condition, the results of the friction coefficient showed
that the presence of boride layers at the surface of AISI 52100 steels denote
solid lubricating features, where this characteristic is increased in lubricant
conditions as a function of the different applied loads.
New Horizons in Coatings and Thin Films
Room: Sunset - Session F2-1
High Power Impulse Magnetron Sputtering
Moderator: D. Lundin, Université Paris-Sud 11, France, J.
Sapieha, Ecole Polytechnique de Montreal, Canada, R.
Bandorf, Fraunhofer Institute for Surface Engineering and
Thin Films IST, Germany
8:00am F2-1-1 Energetic aspects of thin film growth in HiPIMS and in
other pulsed plasmas, L. Martinu (lmartinu@polymtl.ca), J. Capek, M.
Hala, O. Zabeida, J.E. Klemberg-Sapieha, École Polytechnique de
Montréal, Canada INVITED
The microstructure and the resulting properties of coatings and thin films
strongly depend on the growth mechanism which in turn is closely related
to the energetic aspects of surface reactions during the material’s synthesis.
It has been accepted that the microstructural evolution of films grown in
ionized and plasma environments can be well described in terms of the ion
energy and ion flux, or specifically, in terms of the “universal parameter:
the energy per deposited atom”.
Film growth, while under ion bombardment, leads to growth-related effects
such as interfacial atom mixing, high surface mobility (diffusion) of
deposited species, resputtering of loosely bound species, and deep
penetration of ions below the surface, leading to the displacement of atoms
(forward sputtering or knock-in effects). The energy and flux of ions can
generally be controlled, to different levels of selectivity, by the use of ion
beams, by surface biasing, and by the control of plasma density. Compared
to more traditional PECVD and PVD techniques (including DC, pulsed DC,
and medium-, radio- and microwave frequency discharges), there has been a
lot of progress in generating very dense plasmas in pulsed discharges, more
recently in High Power Impulse Magnetron Sputtering (HiPIMS). The latter
technique offers a unique possibility to obtain films from a high flux of
highly ionized materials.
In this presentation, we will critically evaluate the energetic aspects of the
film growth in HiPIMS plasmas, and compare the resulting film
characteristics with those obtained by other techniques. Examples will
include hard protective coatings (conductive or partially conductive), as
well as optical (generally non-conductive) coatings. We will review
different strategies for the control of the deposition process, and discuss
various effects related to the pulse management, to the suppressions of
hysteresis, and to the magnetic field configuration at the target surface.
8:40am F2-1-3 Unique Property of Our Brand New Technology Based
On High Power Pulse Sputtering., S. Hirota
(hirota.satoshi@kobelco.com), K. Yamamoto, Kobe Steel Ltd., Japan, R.
Cremer, KCS Europe GmbH, Germany
We introduce a brand new technology based on High Power Pulse
Sputtering at industrial scale. The New Technology is a magnetron
discharge process like conventional sputtering, however, momentarily input
power is approximately ten times higher in magnitude. Conventional
magnetron sputtering is a low current - high voltage discharge and the
ionization rate of the target material is quite low, usually in the order of a
few percent and the plasma is mainly consisting of gas ions. On the other
hand the New Technology realized stable operation with high current - high
voltage discharge with high ionization rate of the target material and high
deposition rate compared to conventional sputtering. This unique property
is characterized by controlling pulse shape of input power, this means the
film property generated by the New Technology can be modified with great
flexibility.
In this study, we analyzed film property by changing coating condition and
compared with another coating process. For example, different types of
nitride coatings including standard TiAlN were deposited by industrial arc
ion plating (AIP), unbalanced magnetron sputtering(UBMS) and New
Technology . TiAlN coatings deposited by the New Technology process
show strong preferred (111) orientation and a relatively high hardness up to
35 GPa. Whereas AIP TiAlN coatings are characterized by a moderate
hardness up to 30 GPa and (200) or nearly random orientation at an
equivalent substrate bias condition. High magnification image of cross
sectional TEM observations of both coatings revealed that many lattice
defects can be observed for the New Technology coating and is hardened by
many atomic defects, possibly highly stressed as a consequence.
In the presentation, a comparison between AIP, UBMS and the New
Technology coating by different power supply, arc source and deposition
conditions will be shown, not only from property of the coating but also
from industrial perspective such as productivity.
9:00am F2-1-4 Influence of pulse shape and peak current on the
resulting properties of Ti-Si-C composite films deposited by HIPIMS,
R. Bandorf (ralf.bandorf@ist.fraunhofer.de), M. Scholtalbers, G. Bräuer,
Fraunhofer IST, Germany
In recent years the interest in ternary systems, especially so called Mn+1AXn
phases has grown. This interest is motivated by the exceptional structural,
electrical, and mechanical properties of these materials. Besides several
investigations of DC sputtered Ti3SiC2 Alami et al. reported on HIPIMS
deposition. The film structure was reported being columnar, both in dc and
HIPIMS. While the HIPIMS films obtained a dense structure, the dc films
were rough and porous. This paper shows that with HIPIMS deposition
even a featureless glassy structure can be realized, depending on the
deposition parameters. XRR measurements showed that by using HIPIMS
with target current density of approx. 0.5 A/cm 2 a film density of 4.5 g/cm 3 ,
correlating with the bulk value was reached. Furthermore, the resulting
structure and properties (electrical and mechanical) depending on the used
pulse shape during deposition are discussed.
9:20am F2-1-5 Highly ionized carbon plasmas for the growth of
diamond-like carbon thin films with magnetron sputtering, A. Aijaz, K.
Sarakinos, D. Lundin, U. Helmersson (ulfhe@ifm.liu.se), Linköping
University, Sweden
The physical vapor deposition methods, characterized by highly ionized
deposition fluxes of the film forming species, provide added means for the
synthesis of tailor-made materials. Cathodic arc and pulsed laser deposition
are examples of such discharges where electron densities in the order of
10 21 m -3 can be obtained. These techniques, while providing a very high
degree of ionization of the deposition flux, often exhibit several drawbacks,
such as macroparticle ejection from the target, lack of lateral film
uniformity, and difficulty to scale up. Magnetron sputtering based
techniques are technologically interesting, owing to their inherent
advantages of conceptual simplicity, scalability, and film uniformity.
However, electron densities in magnetron discharges are significantly
smaller, in the range of 10 14 -10 16 m -3 and therefore generation of a highly
ionized deposition flux is often difficult. This difficulty is overcome by high
power impulse magnetron sputtering (HiPIMS), where plasma densities on
the order of 10 19 m -3 are achieved. HiPIMS has been successful in
enhancing the ionization for most common metals (Cu, Al, Ta, Ti), but it is
challenged by C. Previous investigations have shown that C + /C ratio in
HiPIMS does not exceed 5% [1]. In the present study we address the low
degree of C ionization by increasing the electron temperature of the plasma.
This is achieved in the HiPIMS discharge by using Ne as sputtering gas
instead of Ar. It resulted in an energetic C + ion population with a three-fold
increase in the total number of C + ions as compared to a conventional
HiPIMS process. The enhanced ionized fraction of carbon facilitates the
growth of carbon films with mass densities as high as approx. 2.8 g/cm 3 as
determined by high resolution x-ray reflectively measurements.
[1] B.M. DeKoven, P.R. Ward, and R.E. Weiss, D.J. Christie, R.A. Scholl,
W.D. Sproul, F. Tomasel, and A. Anders, Proceedings of the 46th Annual
Technical Conference Proceedings of the Society of Vacuum Coaters, May
3-8, 2003, San Francisco, CA, USA, vol., p.158
35 Tuesday Morning, April 24, 2012