Wear and friction of TiAlN/VN coatings against Al2O3 in air at room and elevated temperatures (original) (raw)
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Structure and Wear Mechanisms of Nanostructured TiAlCN/VCN Multilayer Coatings
Plasma Processes and Polymers, 2007
Grown by reactive unbalanced magnetron sputtering in a mixed N 2 and CH 4 gaseous medium, heterogeneous nanocomposite coatings in the Ti-Al-V-N-C system show extraordinarily excellent tribological performance of coated machining tools. Using analytical high-resolution TEM, EELS, FEG-SEM, XRD, and Raman spectroscopy, this paper reports detailed structural and chemical characterization of the coatings grown at various CH 4 : N 2 ratios. Meanwhile, the mechanical and tribological properties were also measured, including hardness, Young's modulus, residual stress and the dry-sliding friction and wear at varying environmental humidity. When CH 4 gas was introduced in the deposition, the structure of the coatings has been found to experience a change from nano-scale TiAlN/VN multilayer architecture to a complex mixture of columnar grains of nc-TiAlV(N,C)/a-C nanocomposites and inter-column network of sp 2 -type amorphous carbon. Carbon incorporation and segregation also shows remarkable influence on the columnar growth model by leading to finer grain size. As compared to the carbon-free nitride coating, the nanocomposite coatings showed substantially reduced residual stress owing to the free-carbon precipitation, whereas the coatings maintained comparable hardness to the carbon-free TiAlN/VN. Their tribological properties were found to be strongly dependent on the environment. In humid air at RH > 30%, the coatings showed low friction coefficient less than 0.4 and extremely low wear rate at a scale of $10 À17 m 3 N À1 m À1 .
Influence of oxide phase formation on the tribological behaviour of Ti-Al-V-N coatings
Surface and Coatings Technology, 2005
Ti-Al-V-N coatings are potential candidates for dry machining applications due to the combination of superior mechanical properties of the Ti 1Àx Al x N phase and the lubricating effects of vanadium oxides formed between 500 and 700-C. The aim of this work was to prepare Ti-Al-V-N coatings with a high V content (25 at.% V in the Ti-Al-V target) to evaluate the influence of the oxides formed, on the friction behaviour during tribological tests up to 700-C. The coatings were deposited by DC magnetron sputtering of a powdermetallurgically produced Ti-Al-V target in an Ar + N 2 discharge. High temperature ball-on-disc tests were used to investigate the tribological properties against alumina balls. Up to temperatures of 500-C only minor changes in tribological properties compared to Ti 1Àx Al x N coatings could be observed. Increasing the testing temperature to 600, 650, and 700-C yields a continuous reduction of the friction coefficient from around 1 to 0.27, respectively. However, during the experiment at 700-C the friction coefficient increases to a constant value of 0.45. Thus, main emphasis was laid on the examination of the formed oxide phases to elucidate their relation to the changing friction coefficients. Scanning electron microscopy investigations, X-ray diffraction and Raman spectroscopy shows that first a V 2 O 5 phase is formed which is responsible for the reduction of the friction coefficient. The further oxidation to form TiO 2 and AlVO 4 on the surface and especially in the wear track (due to the higher local flash temperatures) controls the ongoing oxidation.
Investigating worn surfaces of nanoscale TiAlN/VN multilayer coating using FIB and TEM
Journal of Physics: Conference Series, 2006
TiAlN/VN multilayer coatings exhibit excellent dry sliding wear resistance and low friction coefficient, believed to be associated with the formation of tribo-films comprising Magnéli phases such as V 2 O 5. In order to investigate this hypothesis, dry sliding wear of TiAlN/VN coatings was undertaken against Al 2 O 3. Focused ion beam was used to generate site-specific TEM specimens. A thin (2-20nm) tribo-film was observed at the worn surface, with occasional 'roll-like' wear debris (φ 5-40nm). Both were amorphous and contained the same Ti, Al and V ratio as the coating, but with the nitrogen largely replaced by oxygen. No evidence of Magnéli phases was found.
Tribological Behavior of TiAlN, AlTiN, and AlCrN Coatings at Boundary Lubricating Condition
Tribology Letters, 2018
In this study, ~ 3.5 µm thick multilayer titanium alumina nitride (TiAlN), alumina titanium nitride (AlTiN), and alumina chromium nitride (AlCrN) coatings were deposited on the H13 steel surface by cathodic arc physical vapor deposition (CAPVD) method. The tribological performance of the coatings was evaluated by a tribometer at boundary lubrication condition. Then, coating surfaces were observed by optical microscope, optical profilometer, and atomic force microscope to evaluate the morphological changes, wear volumes, and tribofilm thickness. Also, scanning electron microscopy (energy dispersive X-ray) and X-ray photoelectron spectrometry analyses were applied to coating surfaces for the tribochemical evolution of the tribofilm. Results showed that AlCrN coating performed the best tribological behavior at boundary lubricated condition, when compared to TiAlN and AlTiN coatings and it can be used as a wear resistant cam tappet coating in internal combustion engines.
TEM-EELS study of low-friction superlattice TiAlN/VN coating: the wear mechanisms
Tribology Letters, 2006
A 20-50 nm thick tribofilm was generated on the worn surface of a multilayer coating TiAlN/VN after dry sliding test against an alumina counterpart. The tribofilm was characterized by applying analytical transmission electron microscopy techniques with emphasis on detailed electron energy loss spectrometry and energy loss near edge structure analysis. Pronounced oxygen in the tribofilm indicated a predominant tribo-oxidation wear. Structural changes in the inner-shell ionization edges of N, Ti and V suggested decomposition of nitride fragments.
Tribological Behavior of TiAlNi , AlTiN , AlCrN Coatings Under Dry and Lubricated Conditions
2019
In this study, ~3.5 m thick multilayer TiAlN, AlTiN, and AlCrN coatings were deposited on the H13 steel surface by Cathodic Arc Physical Vapor Deposition (CAPVD) method. The tribological performance of the coatings were evaluated by a tribometer at dry and boundary lubrication conditions. Then, coating surfaces were investigated by optical microscope, optical profilometer and atomic force microscope (AFM) to evaluate the morphological changes, wear volumes and tribofilm thickness. Also, Scanning electron microscopy (SEM/EDX) and X-ray photoelectron spectrometry (XPS) analysis were applied to coating surfaces for the tribochemical evolution of the tribofilm. Results showed that AlCrN coating performed the best tribological behavior at dry and lubricated conditions, when compared to TiAlN and
Applied Surface Science, 2019
Tribochemical analysis of monolithic TaN, TiAlN, and TaAlN coatings deposited by reactive magnetron sputtering onto 316LN stainless steel (SS) substrates are described. Tribology experiments were carried out in ambient atmospheric and high-vacuum sliding conditions to investigate the tribo-atmospheric dependent friction and wear characteristics of these coatings. The lower friction coefficient and improved wear-resistant properties were observed for TaN and TiAlN coatings in the humid atmosphere than in high-vacuum testing condition. Interestingly, lower friction and wear resistance properties of TaAlN coated SS are significantly enhanced in atmospheric as well as high-vacuum sliding conditions because of their highly dense and fine-grained microstructure with stable cubic B1 TaAlN phase. Energy dispersive X-ray spectroscopy elemental mapping and microfocused X-ray photoelectron spectroscopy were carried out on the wear tracks to explore the comprehensive tribo-environment dependent tribochemistry. Formations of alumina (Al 2 O 3) rich tribolayer reduced the friction and enhanced the wear resistance of TaAlN/SS sample tested in atmospheric condition; whereas this coating is highly stable in the high-vacuum condition with higher wear resistance.
Microstructural and Oxidative Mechanical Wear Study on TiAlCN/VCN
2010
About 2.6μm thick TiAlCN/VCN Nanostructured multilayer with periodicity 2.3nm has been deposited by HIPIMS/HIPIMS+UBM technique, where HIPIMS is used for both surface pre-treatment as well deposition. The coatings were produced in industrial sized Hauzer HTC 1000-4 system enabled with HIPIMS technology by sputtering from 2-Vandium and 2-TiAl targets in a mixed CH 4 +Ar+N 2 atmosphere. The HIPIMS plasma composition was studied by Plasma sampling energy resolved mass spectrometer as a function of discharge current. Spectral intensities have shown high metal ion concentration of Ti + , V + , and Al + in the discharge. Significant amount of C + was also observed due to the decomposition of the reactive gas (CH 4) as well as Ar + and N +. As a result highly dense microstructure of the multilayer has been achieved. This has been confirmed through the Cross-sectional TEM analyses. Thermo gravimetric analysis has shown a significant raise of oxidation resistant temperature ≈ 780˚C, in contrast to carbon free TiAlN/VN multilayer coating. High temperature sliding wear test has been conducted on the coatings where friction coefficient was found to be decreasing from μ= 0.6 to μ= 0.4 when the temperature was increased from room to 650˚C. XRD and Raman spectra taken on the wear track of coating has marked the presence of Magnelie phase oxides of the form, V 2 O 5 , VO 2, TiO 2, AlVO 4.