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Nanoscale Multilayered ZrAlN/ZrB2 Coatings Synthesized by Magnetron Sputtering
Dejun LI,

材料科学技术学报 , 2006,
Abstract: Multilayered ZrAlN/ZrB2 coatings containing alternating bilayer periods were synthesized by dc magnetron sputtering technique. The intensities of ZrN (111) or ZrN (200) textures in the structure of the nanolayers depended on the bilayer period as well as N2 gas partial pressure during deposition. Nanoindentation testing showed that hardness and internal stress of the nanolayers varied with the bilayer period and crystallographic orientation in the coatings. The hardness of the nanolayers with bilayer periods of 3~6 nm was enhanced (~27%) over the rule-of-mixture value. A low percent of N2 in processing gas was proved to be benefitial to the synthesis of high hard nanoscale multilayered coatings.
Thermal Residual Stresses in Multilayered Coatings
Xiancheng ZHANG,Binshi XU,Haidou WANG,Yixiong WU,
Xiancheng ZHANG
,Binshi XU,Haidou WANG and Yixiong WU State Key Laboratory of Metal Matrix Composites,Shanghai Jiao Tong University,Shanghai,China National Key Laboratory for Remanufacturing,Beijing,China

材料科学技术学报 , 2005,
Abstract: The mechanical integrity and reliability of coated devices are strongly affected by the residual stresses in thin films and coatings. However, due to the metallurgical complexity of materials, it is rather difficult to obtain a closed-form solution of residual stresses within multilayered coatings (e.g. functionally graded coatings, FGCs). In this paper, an analytical model is developed to predict the distribution of residual stresses within multilayered coatings. The advantage of this model is that the solution of residual stresses is independent of the number of layers. Specific results are obtained by calculating elastic thermal stresses in ZrO2/NiCoCrAIY FGCs, which consist of different material layers. Furthermore, the residual stress distribution near the edges and the stress-induced failure modes of coating are also analyzed. The topics discussed provide some insights into the development of a methodology for designing fail-safe coating systems.
Synthesis and Characterization of Multilayered Diamond Coatings for Biomedical Implants  [PDF]
Leigh Booth,Shane A. Catledge,Dustin Nolen,Raymond G. Thompson,Yogesh K. Vohra
Materials , 2011, DOI: 10.3390/ma4050857
Abstract: With incredible hardness and excellent wear-resistance, nanocrystalline diamond (NCD) coatings are gaining interest in the biomedical community as articulating surfaces of structural implant devices. The focus of this study was to deposit multilayered diamond coatings of alternating NCD and microcrystalline diamond (MCD) layers on Ti-6Al-4V alloy surfaces using microwave plasma chemical vapor deposition (MPCVD) and validate the multilayer coating’s effect on toughness and adhesion. Multilayer samples were designed with varying NCD to MCD thickness ratios and layer numbers. The surface morphology and structural characteristics of the coatings were studied with X-ray diffraction (XRD), Raman spectroscopy, and atomic force microscopy (AFM). Coating adhesion was assessed by Rockwell indentation and progressive load scratch adhesion tests. Multilayered coatings shown to exhibit the greatest adhesion, comparable to single-layered NCD coatings, were the multilayer samples having the lowest average grain sizes and the highest titanium carbide to diamond ratios.
Microstructures and Superhardness Effects of NbN/TaN Nano-multilayer Films

XU Jun-Hua,LI Ge-Yang,GU Ming-Yuan,

无机材料学报 , 2000,
Abstract: The polycrystalline NbN/TaN nano-multilayer films were grown on the substrates of stainless steel by reactive magnetron sputtering. The microstructures and microhardness of the nano-multilayer films were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM) and microhardness tester. The results show that the NbN layers are cubic crystal structure and TaN layers are hexagonal in the NbN/TaN multilayer films. NbN/TaN nano-multilayer films have superhardness effects with a modulation period from 2.3nm to 17.0nm. The maximum hardness HK is 51.0GPa.
Magnetron Sputtered NbN Films with Nb Interlayer  [PDF]
Kulwant Singh,A. C. Bidaye,A. K. Suri
Physics , 2010,
Abstract: NbN films were deposited on SS substrates by reactive DC magnetron sputtering at various N2 flow rates and substrate biasing. Effect of N2 flow rate and substrate biasing has been studied on deposition rate, surface hardness, crystal-structure and adhesion values. Process parameters were optimized for deposition of NbN coatings. NbN coatings were then deposited on to MS substrates as such and with Nb interlayer deposited by magnetron sputtering. The thickness of interlayer was 2 \mum. The duplex coating has been studied for the improvement with respect to surface hardness by Knoop micro indentation and corrosion performance by potentiodynamic polarization technique. Open circuit potentials were also measured.
Temperature-dependence of detection efficiency in NbN and TaN SNSPD  [PDF]
Andreas Engel,Kevin Inderbitzin,Andreas Schilling,Robert Lusche,Alexei Semenov,Heinz-Wilhelm Hübers,Dagmar Henrich,Matthias Hofherr,Konstantin Il'in,Michael Siegel
Physics , 2012, DOI: 10.1109/TASC.2013.2239345
Abstract: We present systematic measurements of the temperature-dependence of detection efficiencies in TaN and NbN superconducting nanowire single-photon detectors. We have observed a clear increase of the cut-off wavelength with decreasing temperature that we can qualitatively describe with a temperature-dependent diffusion coefficient of the quasi-particles created after photon absorption. Furthermore, the detection efficiency at wavelengths shorter than the cut-off wavelength as well as at longer wavelengths exhibit distinct temperature dependencies. The underlying causes and possible consequences for microscopic detection models are discussed.
Magnetron Sputtered NbN Films with Nb Interlayer on Mild Steel  [PDF]
Kulwant Singh,A. C. Bidaye,A. K. Suri
International Journal of Corrosion , 2011, DOI: 10.1155/2011/748168
Abstract: The aim of the study is to extend the NbN coating on MS with Nb interlayer to explore the benefits of hard nitride coatings on low-cost structural material and to compare the coating with NbN monolithic coating on SS. NbN on MS and SS was deposited by reactive d.c. magnetron sputtering at various N2/Ar flow ratios and substrate bias. Deposition rate decreased from 20 to 10?nm/min (without biasing) and from 16 to 8?nm/min (?50?V biasing) when ratio was varied from zero to 70%. Deposition rate decreased with the increase in bias voltage. Coatings showed hexagonal β Nb2N, cubic δ NbN, and hexagonal δ′ NbN as major phases with the increasing N2 flow. Surface hardness reached a maximum of 2040 HK25 at a of 20%. Critical loads, for cohesive and adhesive failure for coating on MS, were between 6–8?N and 9–12?N respectively; for coating on SS, the values were between 7–15?N and 12–25?N respectively. Duplex coatings were studied for hardness by Knoop microindentation, adhesion by scratch tester, and corrosion by potentiodynamic polarization technique. Hardness, adhesion, and corrosion resistance all improved when NbN coating was incorporated with Nb interlayer on MS. 1. Introduction Thin films of binary, ternary, and multicomponent nitride coatings, multilayers, duplex, and nanocrystalline coatings are widely deposited by magnetron sputtering [1–5]. Hard nitride coatings find commercial applications in various industries. TiN, CrN, TiAlN, and so forth have evinced a lot of interest as wear-resistant, protective coatings. Advances in deposition techniques have focused interest in developing novel coating alternatives. Niobium nitride (NbN) films have been investigated primarily for their superconducting properties rather than their mechanical properties. The research for synthesis of NbN film was directed to increase its superconducting transition temperatures [6–8]. However, these are suitable for wear-resistant, protective coatings too. NbN possess good mechanical properties coupled with wear resistance, chemical inertness, high melting point, high temperature stability, and high electrical conductivity, which make NbN films a suitable material for protective coating [9], field emission cathode [10], and diffusion barrier in microelectronic devices [11]. NbN films have been deposited by various techniques, which include reactive magnetron sputtering [12–15], ion beam deposition [16, 17], pulsed laser deposition [18], and cathodic arc deposition [19–22]. In superlattice coatings also, NbN finds use as one-layer component. Superlattice coatings such as TiN/NbN
Superhardness effect of TaN/TiN and NbN/TiN nanostructure multilayers and its mechanism

Yu Li-Hua,Dong Shi-Run,Xu Jun-Hua,Li Ge-Yang,

物理学报 , 2008,
Abstract: 采用射频磁控溅射方法制备单层TaN,NbN和TiN薄膜和不同调制周期的TaN/TiN和NbN/TiN纳米多层膜.薄膜采用X射线衍射仪、高分辨率透射电子显微镜和显微硬度仪进行表征.结果表明TaN/TiN和NbN/TiN纳米多层膜在一定的调制周期范围内均呈共格界面,相应地均出现了超硬效应,且最大硬度值接近.分析了TaN/TiN与NbN/TiN纳米多层膜的超硬机理,TaN/TiN的晶格错配度与NbN/TiN的接近,但TaN/TiN的弹性模量差与NbN/TiN的有一定的差别,表明由于晶格错配使共格外延生长在界面处产生的交变应力场是发生超硬效应的主要因素.
The Tribological Investigations of Multicomponent Multilayered Ion-Plasma Coatings Avinit
A. Sagalovych,V. Sagalovych,A. Kononyhin,V. Popov
Tribology in Industry , 2011,
Abstract: The friction and wear characteristics of sliding friction in conditions of boundary lubrication for coatings, received by ion-plasma method on the heat resistant deformed alloy of АК4-1 type are investigated. Conducted tribological studies of improved designs of multi-component multilayer coatings Avinit in fuel TS-1 media selecting coating materials for precision friction pairsof hydraulical units. Coatings are very effective in increasing the stability of the pair to bores cuffing teasers. Improved coatings have low friction coefficients (0.075 - 0.095) at loads up to 2.0 kN and showed high resistance to wear. More over relative stability increasing achieve 20-80 times, and contrabody wear decrease of 4-5 times.
Structures and Tribological Properties of TiN/TaN Multilayer Coatings Deposited on Silicon Wafer by Magnetron Sputtering

AN Jian~,

摩擦学学报 , 2005,
Abstract: TiN/TaN multilayer coatings consisting of alternate nanometer-scale TiN and TaN layers were deposited on single crystal Si substrates making use of magnetron sputtering technology. The hardness of the resulting TiN/TaN multiplayer coatings was measured. Their structures were analyzed by means of X-ray diffraction, scanning electron microscopy, and 3-D surface profilometry. The friction and wear behaviors of the TiN/TaN multilayer coatings sliding against AISI1045 steel in a pin-on-disc contact mode under unlubricated conditions were evaluated. The wear mechanisms of the composite coatings were discussed based on the analyses of the worn coating surfaces using a scanning electron microscope equipped with an energy dispersive X-ray analyzer attachment and a 3-D surface profilometer. It was found that the TiN/TaN coatings had good modulation periodicity and sharp interface between the TiN and TaN layers. The TiN layer had a cubic structure, but a hexagonal structure emerged from the cubic TaN layer at a modulation period above 8.5 nm. The microhardness, microstructures, and tribological behaviors of the TiN/TaN coatings were closely related to the modulation period. Namely, the TiN/TaN coating deposited at a modulation period of 8.5 nm had the maximum hardness of 31.5 GPa, which was significantly larger than that of the monophase TiN or TaN coating. This was attributed to the hardening effect and superhardening effect of the composite coatings. Subsequently, the TiN/TaN coatings had larger friction coefficients but much better wear resistance than TiN coating. Moreover, the TiN/TaN coatings were dominated by ploughing, adhesion, and local spalling, as they slid against the steel in unlubricated conditions.
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