ICMCTF2013 Session B1-3: PVD Coatings and Technologies

Tuesday, April 30, 2013 8:00 AM in Room Royal Palm 4-6

Tuesday Morning

Time Period TuM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2013 Schedule

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8:00 AM B1-3-1 The Influence of Different Si-Contents of TiAlSiN PVD-Coatings on Mechanical and Tribological Properties at Elevated Temperatures
Tobias Sprute, Wolfgang Tillmann, Fabian Hoffmann (Technische Universität Dortmund, Germany); Yin-Yu Chang (National Formosa University, Taiwan, Republic of China); Yau-Yi Liou (Mingdao University, Taiwan, Republic of China)

TiN and CrN based binary or ternary layers have been used for many years in order to extend the service life of tools for machining. Increasing demands in the industrial use require more efficient layer systems. According to recent studies, silicon opened promising opportunities to influence the characteristics of thin titanium or chromium-based coatings for the better. So nanocomposites as TiAlSiN have an extremely high hardness and a fine grain structure . Furthermore, by the addition of silicon, the oxidation resistance as well as the tribological properties can be increased and improved.

Since these coatings are exposed to high temperatures used in machining processes, the influence of different silicon contents of the Ti/TiN/TiAlSiN multilayer system on mechanical and tribological behavior should be investigated at room temperature and elevated temperatures. In order to adjust different coating compositions and thus modify different silicon contents, various production parameters were systematically varied and tested their effects in detail . Within these studies, the hot working steel AISI H11 was used as the substrate . This steel substrate was previously plasma nitrided to raise the hardness and hence the supporting effect of the substrate opposite to the coating. The structure, the morphology and the different chemical compositions of the silicon-doped coating were investigated by means of scanning electron microscopy with additional device for energy dispersive X-ray spectroscopy. Scratch tests were also performed in order to characterize the quality of the adhesion between the substrate and the multilayer system. The mechanical and tribological properties such as hardness, Young´s modulus, friction and wear coefficient, which were determined using nanoindentation and ball-on-disk tests, as well as the thermal fatigue behavior, which was analyzed by means of an impact tester, were examined at elevated temperatures up to 500°C.

8:20 AM B1-3-2 Compositional, Structural and Mechanical Evolution of Reactively and Non-reactively Sputtered Zr-Al-N Thin Films
Paul Mayrhofer (Vienna University of Technology, Austria); Doris Sonnleitner (Montanuniversität Leoben, Austria); Jörg Paulitsch (Vienna University of Technology and and Montanuniversität Leoben, Austria); David Holec (Montanuniversität Leoben, Austria)
The compositional and structural evolution of Zr1-xAlxN thin films as a function of the N2-to-total pressure ratio (pN2/pT) during reactive magnetron sputtering is investigated in detail and compared with non-reactively prepared films. We therefore used powder-metallurgically (PM) prepared Zr0.7Al0.3, Zr0.6Al0.4 and ZrN0.6AlN0.4 targets (Plansee). Reactive sputtering was conducted with pN2/pT of 12, 25 and 50%. Based on these studies we can show that the Al incorporation to the prepared films as well as their crystalline structure is highly dominated by the N2-to-total pressure ratio used. These findings are correlated with the resulting film structure, chemical composition, morphology and mechanical properties. For the coatings deposited with pN2/pT=12% a well-defined cubic (c) structure is obtained with high hardness values of 28-32 GPa . Annealing treatments lead to recovery effects and decomposition related processes of their super-saturated c-Zr1-xAlxN phases. The hardness of the coating prepared from the Zr0.7Al0.3 target with pN2/pT=12% increases from ~32 to ~35 GPa upon annealing to 1100 °C . After annealing at 1500 °C the coatings are composed of their stable constituents c-ZrN and wurtzite structure w-AlN. When the coatings are prepared with higher N2-to-total pressure ratios (e.g., pN2/pT=25 and 50%) their structure becomes nanocrystalline, most likely due to the competitive growth of cubic, hexagonal and amorphous phases, as suggested by X-ray diffraction (XRD). Due to the smaller supersaturated cubic phase content (as compared to the coating prepared with pN2/pT=12%), their hardness is only ~20 GPa. Annealing of these coatings leads to no significant changes in structure or hardness up to Ta ~1100 °C. This is supported by DSC, exhibiting only at temperatures above 1100 °C pronounced reactions, which are also connected with a pronounced N2-release. Preparing the films non-reactively from ZrN0.6AlN0.4 targets lead to well-defined crystalline single-phase c-Zr0.68Al0.32N coatings with hardnesses of ~32 GPa. The hardness slightly increases to ~33 GPa for annealing at temperatures to 1200 °C. Up to this temperature no formation of w-AlN can be detected by XRD. The study highlights the importance of the particle energy delivered to the growing film material to prepare well-crystalline coatings with high thermal stability.
8:40 AM B1-3-3 Mechanical and Antimicrobial Characteristics in Zr-based Thin Film Metallic Glasses at Various Processing Temperature
Jia-Hong Chu, Hsien-Wei Chen, Jenq-Gong Duh (National Tsing Hua University, Taiwan, Republic of China); Jyh-Wei Lee (Ming Chi University of Technology, Taiwan, Republic of China); JasonShian-Ching Jang (National Central University, Taiwan, Republic of China)
This study aims to investigate the effects of various deposition temperature on antimicrobial and mechanical properties in Zr-based thin film metallic glass (TFMG) fabricated by magnetron sputtering. The crystallography and chemical composition are analyzed by grazing incidence X-ray diffractometer (GIXRD) and electron probe micro-analyzer (EPMA), respectively. The microstructural features are observed through scanning electron microscope (SEM) and transition electron microscope (TEM). Enhanced hardness and modulus with temperature measured by nanoindentation are attributed to the shortening of average atomic distance and the increase of the short range ordered clusters. The antimicrobial performance of specimens is tested through inoculation and liquid culture methods. Antimicrobial activity is evaluated by copper ions released as well as plate count methods used against Escherichia coli and Staphylococcus aureus. The results show that the surface of 304 stainless steel substrate can be modified with deposited ZrCuNiAlSi TFMG, and their improved antimicrobial efficacy against those bacteria is attributed to their amorphous nature, hydrophobic properties and released copper ions. The TFMG developed in this study with adequate hardness and antimicrobial abilities can be used as a promising candidate to improve the surface properties of the medical appliances and also to reduce the possibility of nosocomial infection.
9:00 AM B1-3-4 Incorporation of Nano-crystalline TiB2 Layers in Zr-Cu-Ni-Al Thin Film Metallic Glasses for Improved Anti-wear Characteristics
Yu-Chen Chan, Hsien-Wei Chen, Jenq-Gong Duh (National Tsing Hua University, Taiwan, Republic of China); Jyh-Wei Lee (Ming Chi University of Technology, Taiwan, Republic of China)
To suppress the strain localization, inhomogeneous plastic deformation and brittle nature in thin film metallic glasses (TFMGs) is becoming highly valued. Accordingly, the current study attempts to provide a new strategy to attack this tough issue. Quaternary Zr-Cu-Ni-Al TFMGs/TiB2 multilayer coatings with specially designed bilayer periods are deposited on silicon wafers and tool steels by r.f. reactive magnetron sputtering. Intrinsic hardness of multilayers obtained from nano-indenter is much higher than the average value calculated by rule-of-mixture. The SEM images of indents clearly verify that the shear bands are significantly distorted with incorporation of nano-crystalline TiB2 layers. The multilayer configuration also shows a significant enhancement in tribological performance, as evaluated by nano-scratch and ball-on-disc tests. The improved mechanical properties mainly result from structure barrier effect and Hall-Petch relation, which effectively restrict the mutual propagation of shear bands and dislocations. Further microstructure and texture characterizations by TEM and corresponding dark-field images reveal the dependence for the thickness of TiB2 layers on such a unique strengthening mechanism.
9:20 AM B1-3-5 Corrosion Resistance of Amorphous, Nanocomposite, and Nanocrystalline Cr-C Films Deposited by Magnetron Sputtering
Kristian Nygren, Matilda Andersson, Jonas Högström, Wendy Fredriksson, Kristina Edström, Leif Nyholm, Ulf Jansson (Uppsala University, Sweden)

Crystalline chromium carbide (Cr-C) thin films are known to possess excellent corrosion resistance in acidic and saline media. Growth of crystalline Cr-C by sputtering typically requires a substrate temperature above 500 °C, which prevents hardened steels and other temperature-sensitive substrates from being coated without adversities. We have observed that sputtered low-temperature films can be described as an amorphous nanocomposite with two non-crystalline phases: amorphous CrCx and amorphous carbon (a-C). One interesting feature of amorphous Cr-C is the lack of grain boundaries which would eliminate grain boundary corrosion. On the other hand, large stable crystallites mean that corrosive attacks need to overcome a high energy threshold. The absence of carbide grains in amorphous films may therefore lower the overall corrosion resistance. The objective of this study is to investigate the influence of the deposition temperature and the composition on the microstructure of Cr-C films, as well as their corrosion resistance.

Cr-C thin films with 25-85 at% C were deposited at 20-700 °C by direct current magnetron sputtering from elemental targets under UHV conditions. XRD and TEM show that films deposited at 20–300 °C are amorphous. An increase of the temperature to 500 °C leads to a transformation from amorphous to nanocrystalline Cr7C3 or nanocomposite Cr-C/a-C films depending on composition. XPS shows that the amorphous CrCx phase has a composition close to crystalline Cr7C3. There is no shift in the C1s core level binding energy between amorphous and crystalline Cr7C3 films, which indicates a similar short-range chemical order. XRD reflections from Cr3C2 were observed at 700 °C and this phase was accompanied by a positive shift in the C1s spectra. The corrosion resistance has been investigated by polarization curves, chronoamperometry, XPS, and SEM. The amorphous films are less oxidation resistant than the more crystalline films. Generally, higher deposition temperature results in lower accumulated charge in chronoamperometry. Films deposited at 500 °C have a 50% reduction in charge when compared to films deposited at 20 °C, and post-corrosion XPS shows a similar trend in the amount of surface oxides. More a‑C phase also lowers the corrosion current. Raman spectroscopy shows that the hybridization of the a-C phase is predominantly sp2, which contribute to a relatively low hardness around 7‑10 GPa. Reactively sputtered nanocomposite films have previously been shown to yield a low coefficient of friction (0.13), which suggests that the studied films are candidates to enhance properties of steel in combined corrosive and tribological environments.

9:40 AM B1-3-6 Corrosion Resistance and Tribological Properties of CrN, CrN/SiC, and CrN/DLC Coatings Grown by Cccelerated Plasma Arc Deposition
David Bell (Phygen Coatings, Inc., US); Christopher Mulligan, Maira Senick (US Army ARDEC, Benet Laboratories, US); Viktor Khominich, Zack Gay (Phygen Coatings, Inc., US)

CrN monolayers along with CrN/SiC and CrN/DLC duplex layers up to 5 μm thick were grown by accelerated plasma arc deposition on 4340 steel substrates. The layers exhibit a dense and defect free microstructure. The tribological properties were evaluated with dry ball-on-disk sliding tests against an alumina counterface at room temperature. The CrN monolayer exhibits a coefficient of friction, μ = 0.28, while CrN/SiC and CrN/DLC duplex exhibit much lower μ = 0.08 and 0.06, respectively. The low friction is attributed to the top layers of amorphous SiC and DLC, respectively. The wear rates of the coatings were very low and measured as 5.3x10-7, 7.3x10-7, and 7.9x10-7 mm3/Nm, respectively, for CrN, CrN/DLC, and CrN/SiC. Corrosion resistance was evaluated in both cyclical environmental testing as well as quantitatively via potentiodynamic corrosion tests in sodium chloride solution. The corrosion resistance in both cases is compared to standard electroless Ni and electroplated Cr coatings. The highest level of corrosion resistance was observed for the CrN monolayer and CrN/SiC duplex layer. Both exhibit improved corrosion resistance over electroplated Cr coatings and comparable corrosion resistance to electroless Ni coatings. This high level of corrosion resistance is remarkable for physical vapor deposited thin nitride layers. The accelerated plasma arc deposited materials show great promise for applications in which a combination of low friction, wear resistance, as well as corrosion resistance are required.

10:00 AM B1-3-7 Comparative Study of Transition Metal Boronitride Hard Coatings Fabricated by Reactive Magnetron Sputtering Process
Jyh-Wei Lee, Li-Wei Ho (Ming Chi University of Technology, Taiwan, Republic of China); Wen-Shiang Lai, Chaur-Jeng Wang (National Taiwan University of Science and Technology, Taiwan, Republic of China)
The boron containing transition metal nitride hard coatings have been studied by researchers and applied in industries intensively due to their high hardness, good wear, corrosion and oxidation resistance. In this work, the ternary and quaternary Cr-B-N, Cr-Ti-B-N, Ti-Cr-B-N and Ti-Zr-B-N coatings were co-deposited by magnetron sputtering of Cr plus CrB2, Cr plus TiB2, Ti plus CrB2 and Ti plus ZrB2 targets, respectively, in a reactively gaseous mixture. Comparative studies on microstructure, mechanical, adhesion, tribological properties and corrosion resistance of Cr-B-N, Cr-Ti-B-N, Ti-Cr-B-N, and Ti-Zr-B-N coatings with various Cr, Ti, Zr and B contents were conducted. The structure and phase composition of coatings were determined by X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The mechanical properties of the coatings were measured using nanoindentation, HRC-DB and scratch tests. The tribological properties were evaluated in air using conventional ball-on-disc tribometer. The electrochemical tests were performed in 3.5 wt.% NaCl medium. The maximum hardness reaching ~34 GPa was found for the Ti-Cr-B-N and Ti-Zr-B-N coatings. The nanocomposite structured transition metal boronitride coatings showed a better corrosion resistance than that of the coatings with columnar structures. The effects of boron and transition metal contents on the hardness, microstructure and phase evolution of quaternary transition metal boronitride coatings were also discussed.
10:40 AM B1-3-9 Using Filtered Vacuum-arc Plasma for PIII&D Process of Ti-Al-Y-N Coatings and their Abrasive and Cavitation Resistance
Vitaliy Belous, Volodymyr Vasyliev, Alexandr Luchaninov, Volodymyr Marinin, Elena Reshetnyak, Volodymyr Strel’nitskij (National Science Center “Kharkov Institute of Physics and Technology”, Ukraine); Sergiy Goltvyanytsya, Volodymyr Goltvyanytsya (Real Ltd., Ukraine)

Deposition from the filtered vacuum arc plasma is the widely used effective method of manufacturing high quality protective wear resistant coatings. Ti-Al-Y-N coatings with small Y percentage have demonstrated high hardness and excellent oxidation resistance which provides their application for protection the machine parts which operate under extreme environmental conditions. In our recent work [1] we investigated structure and properties of such coatings prepared by the plasma immersion ion implantation and deposition (PIII&D) using filtered vacuum-arc plasma source.

A high-voltage pulsed bias applied to the substrate permits the deposition of thicker coatings with good adhesion and low residual stresses. I n the present work we examined the cavitation and abrasion resistance of PIII&D deposited Ti-Al-Y-N coatings doped with yttrium (≤ 1 at.%) and analyzed correlation between their properties and structure.

Ti0.5‑xAl0.5Yx alloys (x = 0, 0.002, 0.004, 0.01) produced by vacuum-arc remelting were used as cathodes in the vacuum-arc plasma source. Ti-Al-Y-N coatings with thickness of 5-6 micron were deposited on the 302 stainless steel substrates from filtered vacuum-arc plasma at nitrogen pressure of 0.1 Pa.

The substrate potential was either DC (-150 V) or negative pulsed, the amplitude AU varied in the range of 0-2.5 kV.

The erosion resistance of the coatings was evaluated on the measured mass loss during cavitation treatment in distilled water. The tests were continued until visually watched open-ended pores in the coating were formed. Abrasion wear was determined in the scheme substrate plane – rotating abrasion disk. Adhesion properties, friction coefficient and wear resistance were determined using equipment by CSM Instruments.

The substrate potential during deposition process and Y content in the coatings were found to be important factors influencing the rate and character of their cavitation damage. The coating deposited at AU=0 was subjected to pitting erosion. Long cracks prevailed on the surface of the cavitation treated coating deposited at DC (-150 V) potential. High voltage pulsed substrate potential contributed to decrease by 3-5 times in the rate of the mass loss under cavitation, quantity of the erosion defects on the treated surface diminishes sharply. Increase of Y content resulted in improvement of wear durability. Mean rates of cavitation and abrasion wear of (Ti,Al)N+1at.%Y were several times lower than that of (Ti,Al)N and TiN.

[1] V.A. Belous et al. Surf. Coat. Technol. 206 (2011) 1720.

11:00 AM B1-3-10 Nanocomposite Mo-Ag-N Self-lubricating Hard Coatings Fabricated by Magnetron Sputtering
Junfeng Yang (Institute of Solid State Physics, Chinese Academy of Sciences, China)
Mo-Ag-N nanocomposite coatings were prepared by d.c. magnetron sputtering technique from a Mo target with embedded Ag pellets onto Si substrates, followed by vacuum annealing at temperature of 425, 500, and 600 oC for 1hour. SEM, EDS, XRD, nanoindenter, and micro-macro tribometer were used to investigate the influence of Ag content and annealing temperature on microstructure, surface morphology and mechanical properties. As-deposited Mo-Ag-N coatings consisted of fcc γ-Mo2N phase and fcc Ag phase where Ag uniformly distributed into Mo-N matrix. The hardness of Mo-Ag-N coatings initially increased to maximum value of 32 GPa for coatings containing 6 at.% Ag and then decreased with the further increase of Ag, whereas friction coefficient decreased monotonously with the increase of Ag content. With the increase of annealing temperature hardness, friction coefficient, and wear resistance decreased due to accumulation of a large amount of Ag particles or agglomerations onto surface resulted from high temperature intriguing phase segregation or diffusion.
Time Period TuM Sessions | Abstract Timeline | Topic B Sessions | Time Periods | Topics | ICMCTF2013 Schedule