ICMCTF 2012! - CD-Lab Application Oriented Coating Development

properties, composition and surface morphology were investigated as a
function of the Si + kinetic energy. These properties were studied using the
following characterization techniques: Raman spectroscopy, X-ray
diffraction, nanoindentation, X-ray Photoelectron Spectroscopy and
Scanning Electron Microscopy. It was found that the Si content, which was
varied from 1.6 to 3.5 at.%, depends, approximately linearly, on the silicon
ion kinetic energy. Ti-Si-N films with hardness as high as 34.0 GPa, which
is suitable for many mechanical applications, were obtained. The hardness
was strongly affected by the silicon ion energy, and there exists an optimal
energy value, and consequently a certain value of Si content at which the
maximum hardness is reached. These results show that the properties of the
deposited material are controlled partially by the Si + kinetic used for thin
film growing.
BP-20 The Role of Aluminium for the Nanostructure and Mechanical
Properties of Sputtered Ti-B Films, P. Epaminonda, University of
Cyprus, Cyprus, K. Polychronopoulou, Northwestern University, US, K.
Fadenberger, Robert Bosch GmbH, Germany, M. Baker, University of
Surrey, UK, P. Gibson, Joint Research Centre, Italy, A. Leyland, A.
Matthews, University of Sheffield, UK, P.H. Mayrhofer, Montanuniversität
Leoben, Austria, C. Rebholz (claus@ucy.ac.cy), University of Cyprus,
Cyprus
TiB2 thin films have been studied extensively due to their outstanding
properties (e.g. high hardness, high thermochemical stability), making them
highly attractive for many applications in erosive, abrasive, corrosive and/or
high-temperature environments. Despite their excellent properties, the
usability and commercialisation of TiB2 films has been mainly hindered due
to their brittleness and limited film-substrate adhesion, caused by the
primarily strong covalent bonding in the hexagonal B network and the high
compressive stresses developed in deposited films on various substrates. An
effective route for improving adhesion and toughness in hard ceramic films
is the introduction of ductile metal additions (e.g. Al) or layers, therefore
modifying their bonding type and structure.
In this study, TixAlyB2 thin films (0.88≤ x ≤1.04; 0.12≤ y ≤0.31), with Al
contents between 4.1-9.4 at.%, were deposited onto Si (100) and AISI 316
stainless steel substrates by simultaneous co-sputtering from TiAl and TiB2
targets in an argon discharge at 170˚C. The coating stoichiometry, relative
phase composition, nanostructure, density and mechanical properties were
determined using X-ray photoelectron spectroscopy (XPS), X-ray
diffraction (XRD) and Laser Acoustic Surface Waves (LAwave), in
combination with nanoindentation measurements. It is shown that Al
substitutes for Ti in stoichiometric closed-packed hexagonal nanocrystalline
thin films with 4.1 at.% Al, having an average grain size of 2-3 nm. As the
Al concentration is increased, the crystallinity, average TiB2 grain size,
density, hardness and elastic modulus decreases from ~2-3 to 1 nm, 4.2 to
3.8 g/cm 3 , 32.9 to 20.6 GPa and 335 to 250 GPa, respectively, while the
film adhesion increases. Density and elastic modulus from ab initio
calculations are compared to experimental results. The elastic modulus
values measured by nanoindentation are lower than the calculated ab initio
data, attributable to the nanocrystalline nature of the deposited films.
BP-21 Microstructural characteristics of CrZrSiN coatings synthesized
by unbalanced magnetron sputtering with CrZrSi segment targets,
Kim, S.Y. Lee (sylee@kau.ac.kr), Korea Aerospace University, Republic of
Korea
Segment target have several advantages and theoretically it is possible to
deposit almost all materials and to synthesize various multicomponent
coatings without much difficulties. It does however remains a bigh
challenge to control the composition and microstructure of the coatings
synthesized using segment targets. In this work, CrZr-Si-N films were
synthesized by unbalanced magnetron sputtering with CrZrSi segment
target. Three type segment targets with various volumne ratios of (Cr+Zr)
and Si (each ratio is 11:1vol%, 5:1vol% and 3:1vol %) used in this work.
Characteristics such as crystalline structure, surface morphology, hardness
and chemical composition as a function of the Si content were investigated
by X-ray diffraction (XRD), field emission scanning electron microscope
(FE-SEM), transmission electron microscope(TEM), atomic force
microscopy (AFM), microhardness tester, and glow discharge optical
emission spectroscopy (GDOES). The surface images of the coatings were
revealed that the coatings have dense and compact microstructure and very
smooth surface and the surface roughness decreased as Si content in the
coatings increased. The microstructure of coatings were consisted of mainly
Cr(Zr)N crystalline and Si3N4 amorphous. The hardness of films
approximately 32GPa was maintained up to 10% Si content and further
increase in Si contents above 10% in the coatings seemed to decrease the
hardness of the coatings below approximately 24GPa. Detailed
experimental result will be presented.
Thursday Afternoon Poster Sessions 100
BP-22 Synthesis and characterization of CrZrAlN coatings synthesized
by unbalanced magnetron sputtering, J.Y. Kim (kimjjyu@naver.com),
D.J. Kim, B.S. Kim, S.Y. Lee, Korea Aerospace University, Republic of
Korea
The Cr-Zr-N films have much improved mechanical properties and very
smooth surface roughness. However, even though their outstanding
properties, the Cr-Zr-N coatings revealed their mechanical properties
deteriorated severely with increasing Zr content at 500� due to very rapid
oxidation. Addition of Al into the CrZrN coatings is expected to improve
the high temperature properties of the coatings as Al provides excellent
oxidation resistance the Cr-Zr-N coatings. In this study, the quaternary Cr-
Zr-Al-N films with various Al contents were synthesized using CrZrAl
segment target by unbalanced magnetron sputtering. The characteristics of
films were investigated by X-ray diffraction (XRD), Field Emission-
Scanning Electron Microscope (FE-SEM), atomic force microscopy (AFM),
glow discharge optical emission spectroscopy (GDOES), and microhardness
tester. Preliminary results show that the Cr-Zr-Al-N coatings had
outstanding mechanical properties with various Al contents at high
temperature especially high temperature thermal stability of the coatings.
Detailed experimental results will be presented.
BP-23 Mechanical Performance and Nanoscaled Deformation of Bias-
Sputtered (AlCrTaTiZr)NCy Multi-component Coatings, S.Y. Lin, S.Y.
Chang (shouyi@dragon.nchu.edu.tw), Y.C. Huang, F.S. Shieu, National
Chung Hsing University, Taiwan
This work develops (AlCrTaTiZr)NCy multi-component carbo-nitride films,
with the incorporations of quinary metallic elements, nitrogen and carbon,
as protective hard coatings by co-sputtering of AlCrTaTiZr alloy and
graphite in an Ar/N2 mixed atmosphere with the application of different
substrate biases. All the (AlCrTaTiZr)NCy films deposited at different
conditions exhibited a simple face-centered cubic structure. As the applied
substrate bias and graphite-target power increased, the deposited
(AlCrTaTiZr)NCy coatings transformed from a large columnar structure
with a (111) preferred orientation to a nanocrystalline or even nearamorphous
structure. With increasing substrate bias and graphite-target
power, the hardness and H/E ratio of the coatings increased from 18 GPa
and 0.07, to much higher values of about 32 GPa and 0.12, respectively,
attributed to the densification of the coatings, the introduction of covalentlike
carbide bonds, the refinement of grains and the formation of
nanocomposite structure. Because of the severe lattice distortions in the
multi-component coatings caused by the addition of differently-sized atoms,
the dominant deformation mechanism of the coatings was found to be the
formation of stacking faults, rather than complete dislocations only.
BP-24 Effects of Substrate Temperature and Bias-Voltage on
Mechanical Properties and Oxidation Resistance of TiAlYN Films, N.
Hattori (sunmoonstone@live.jp), Keio University, Japan, T. Takahashi,
Yungaloy Corporation, Japan, M. Noborisaka, T. Mori, M. Takahashi, T.
Suzuki, Keio University, Japan
It is well known that TiAlN films have been preferred in cutting tools for
their mechanical properties and good oxidation resistance. However, many
studies have reported that they oxidize over 800 ºC. The addition of another
element into matrix is one of the techniques to improve the properties. In
our previous researches, we reported on the effect of yttrium addition to
TiAlN films and investigated the mechanical and thermal properties. It was
concluded that the films with the yttrium content 2 at.% showed the highest
hardness and excellent oxidation resistance up to 900ºC.
In this study, we synthesized Ti49Al49Y2N films changing substrate
temperatures at 100ºC, 200ºC, 300ºC, 400ºC and bias-voltages at 50 V, 100
V, 200 V, 300 V and investigated their oxidation resistance and mechanical
properties. The films were deposited on Si, WC-Co, and SUS304 substrates
by the cathodic arc ion plating (AIP) method. The hardness and adhesion
were analyzed by a micro-Vickers hardness tester and Rockwell hardness
tester, respectively. For the evaluation of the oxidation resistance, X-ray
diffraction (XRD) and glow discharge optical emission spectrometry
(GDOES) were performed to identify oxide layers of the films annealing at
900ºC for 1 hour in air.
The hardness of all films doped yttrium increased, they were about 33 GPa.
The films deposited at a substrate temperature of 200ºC showed an
excellent substrate adhesion and oxidation resistance. The difference in
hardness and oxidation resistance was not observed changing bias-voltage.
The results demonstrated that Ti49Al49Y2N films deposited at bias voltage at
100 V and substrate temperature at 200ºC showed high hardness and the
oxidation resistance keeping the adhesion strength.