Tribological characterization of tungsten nitride coatings deposited by reactive magnetron sputtering

The structure, hardness, friction and wear of tungsten nitrides prepared by d.c. reactive magnetron sputtering were investigated. The coatings were deposited with different nitrogen to argon ratios; the total pressure was kept constant. The tribological tests were performed on a pin-on-disc tribometer in terrestrial atmosphere with 100Cr6 steel, Al₂O₃ and Si₃N₄ balls as sliding counter-bodies. The wear tracks, the ball-wear scars and the wear debris were analysed by scanning electron microscopy in order to characterize the dominant wear mechanisms.The coatings exhibited different phases as a function of the nitrogen content: films with low N content exhibited the α-W phase; β-W phase was dominant for nitrogen contents from 12 to 15 at.% and β-W₂N was observed for nitrogen content higher that 30 at.%. The mechanical and tribological properties of the tungsten nitride coatings were strongly influenced by the structure. The hardness and the Young's modulus values were in the ranges (29–39 GPa) and (300–390 GPa), respectively; the lowest values correspond to the coatings with the highest nitrogen content. Generally, the friction and wear rate of tungsten nitride coatings sliding against ceramic balls increased with nitrogen content reaching a maximum at 12 at.%; further increase of the nitrogen content led to a decrease of the friction and wear. The sliding with the steel balls did not wear the coatings under the selected testing conditions.     

磁控溅射法制备的五氧化二钒薄膜光电特性

利用射频磁控溅射方法,选取溅射时间为15,25,30和45min,在蓝宝石衬底上沉积了V2O5薄膜。研究了其他实验参量不变,溅射时间不同对薄膜结构、薄膜厚度、表面形貌、电学及光学性能的影响。实验结果表明,制备出的薄膜为单一组分的V2O5薄膜,其在(001)面有明显的择优取向。随着溅身时间的增加,结晶性能逐渐变强,晶粒尺寸也逐渐变大,而表面粗糙度值会逐渐降低;在晶体结构完整的基础上,随着溅射时间的增加,相变温度和经历的温度范围会逐渐增加,电学突变性能会降低。测试了薄膜在中红外波段的高低温透过率,结果显示:当膜厚为350nm,波长为5μm时,薄膜的透过率从25℃时的81%变为300℃的7%,变化幅度可达74%;所有薄膜相变前后透过率的比值均为9~13,表现出了非常突出的光学开关特性。     

Tribological behavior of TiN films depositid by reactive magnetron sputtering under low pressure

The effect of deposition conditions on the tribological behavior of titanium nitride thin films produced by reactive magnetron sputtering has been studied. Dependences of the hardness, the width of the friction track, the friction coefficient, and the volume wear of the TiN films on the N₂ reactive gas flow rate have been obtained. Conditions of deposition under which the coatings with the best tribological characteristics are formed have been determined.     

Fractal characteristics and microstructure evolution of magnetron sputtering Cu thin films

How to describe surface morphology characteristic and microstructure evolution are the hottest researches of current thin film researches.But in traditional characterization of surface morphology,the roughness parameters are scale related.And the microstructure evolution of thin film during post-treatment is usually not considered in detail.To give a better understanding of the roughness of thin films topography,fractal method is carried out.In addition,microstructure evolution of thin films is analyzed based on the crystallography and energy theory.Cu thin films are deposited on Si(100) substrates by magnetron sputtering,and then annealed at different temperatures.Surface topography is characterized by atomic force microscope(AFM).Triangular prism surface area(TPSA) algorithm is used to calculate the fractal dimension of the AFM images.Apparent scale effect exists between the surface morphology roughness and film thickness.Relationship between the fractal dimension and roughness is analyzed by linear regression method and linear relationship exists between fractal dimension and surface roughness root mean square(RMS).Fractal dimension can be characterized as a scale independence parameter to represent the complex degree and roughness level of surface.With the increase of annealing temperature,surface roughness and fractal dimension decrease.But when the annealing temperature exceeds the recrystallization temperature,due to the agglomeration and coalescence of Cu grain,surface roughness and fractal dimension increase.Scale effect and changing regularity of grain growth and shape evolution for different film thickness under different annealing temperatures are analyzed.Based on minimum total free energy,regularity of grain growth and changing is proposed.The proposed research has some theory significance and applicative value of Cu interconnect process and development of MEMS.     

Wear resistant TiMoN coatings deposited by magnetron sputtering

TiMoN coatings with different Mo concentrations were deposited using a reactive magnetron sputtering technique and characterized by X-ray diffraction, nano-indentation, pin-on-disc testing, SEM/EDS and X-ray photoelectron spectroscopy. Mo alloying of TiN coatings generally enhances hardness. When tested in a pin-on-disc test against WC-Co pin, the coefficients of friction of TiMoN coatings were found to decrease with the increase in Mo atomic fraction, with the lowest values (0.4-0.5) being only one-half that of TiN coating (1.03). The underlying mechanism of the Mo effect is the formation of lubricious MoO₃ on the wear track. The combination of low coefficient of friction and enhanced hardness reduces the wear rate of TiMoN coatings to less than 2.5% of the wear rate of TiN coating.     

Rhodium coated mirrors deposited by magnetron sputtering for fusion applications

Metallic mirrors will be essential components of all optical spectroscopy and imaging systems for ITER plasma diagnostics. Any change in the mirror performance, in particular, its reflectivity, due to erosion of the surface by charge exchange neutrals or deposition of impurities will influence the quality and reliability of the detected signals. Due to its high reflectivity in the visible wavelength range and its low sputtering yield, rhodium appears as an attractive material for first mirrors in ITER. However, the very high price of the raw material calls for using it in the form of a film deposited onto metallic substrates. The development of a reliable technique for the preparation of high reflectivity rhodium films is therefore of the highest importance. Rhodium layers with thicknesses of up to 2 microm were produced on different substrates of interest (Mo, stainless steel, Cu) by magnetron sputtering. Produced films exhibit a low roughness and crystallite size of about 10 nm with a dense columnar structure. No impurities were detected on the surface after deposition. Scratch tests demonstrate that adhesion properties increase with substrate hardness. Detailed optical characterizations of Rh-coated mirrors as well as results of erosion tests performed both under laboratory conditions and in the TEXTOR tokamak are presented in this paper.     

Tribological and electrochemical performances of Cr/CrN and Cr/CrN/CrAlN multilayer coatings deposited by RF magnetron sputtering

CrN/CrAlN and Cr/CrN/CrAlN multilayers were grown with dual RF magnetron sputtering. The application of these multilayers will be wood machining of green wood. That is why ball-on-disc and electrochemical tests in NaCl aqueous solution were realized to elucidate the tribological and corrosion behavior of these coatings as they will be exposed to wear and corrosion during wood machining process. The samples/alumina and samples/WC coupling showed different wear mechanisms. The 300 nm thick Cr/CrN/CrAlN multilayer demonstrated the best tribological behavior and corrosion resistance. The influence of growth defects on corrosion resistance has been shown.     

多工位磁控溅射镀膜系统膜厚均匀性的研究

本文建立了多工位公自转磁控溅射系统镀膜过程的物理模型,通过把基片运动与镀膜过程的模拟结合在一起,运用时间步长划分的算法仿真公自转系统下矩形靶沉积的三维膜厚分布,并使用同样的方法计算纯自转磁控溅射系统沉积薄膜的厚度分布,最后将两个结果进行对比.研究表明,随着自转与公转速度比例的调节,公自转系统在最优转速比0.5时所制得的薄膜厚度均匀性较纯自转系统得到明显地改善,此结论与实验结果保持一致.     

磁控溅射制备碳化硼薄膜的结构与成分分析

近年来国际上³He资源的短缺造成了基于³He的中子探测器高昂的成本,而以碳化硼薄膜作为中子转换层的硼基中子探测器逐渐成为了最有前景的替代方案。通过直流磁控溅射制备了Ti/B₄C多层膜,并使用透射电子显微镜（TEM）、飞行时间二次离子质谱（ToF-SIMS）、X射线光电子能谱（XPS）等手段对薄膜的结构与成分进行表征。结果表明：Ti层存在结晶情况;H、O、N元素为薄膜内部的主要杂质,且多分布于Ti层与B₄C-on-Ti过渡层中;更高的本底真空度能够降低碳化硼薄膜内的杂质含量,提高B含量占比;中子探测效率测试结果证明本底真空度的提高能够有效提高碳化硼中子转换层的效率。     

Friction and wear response of nitride coating deposited through PVD magnetron sputtering

Surface engineering with applied coating plays a vital role in any industrial application. These coatings are meant for better mechanical and tribological characteristics when applied on to the materials. The major challenge in selecting a suitable coating strategy is their input process parameters. There are several parameters which influences the coating properties, but it is hard to choose one of them and ignoring others. Multilayers of tungsten nitride are attracting great interest to modulate their tribological and mechanical properties through physical vapour deposition process due to their wide application range. These multilayer nitride films were deposited through unbalanced reactive magnetron sputtering technique. The tribological tests were performed on a pin-on-disc tribometer at room temperature and it has been observed that friction and wear values reduce drastically while applying multilayer coatings. Later, artificial neural network (ANN) is employed to optimize the tribological properties of sputtered coatings.     

基于DSP的直流磁控溅射电源设计

该文通过研究磁控靶工作时的负载特性,设计了以全桥逆变开关电源技术为基础的高效、大功率磁控溅射电源。利用Matlab搭建的模型对电路的参数、输出波形进行了仿真,在仿真的基础上完成了主回路、控制电路硬件及软件程序的设计及样机测试,并在JTP-1400型磁控溅射镀膜机上进行了实验。实验结果证实该电源具有恒流控制效果好,电流截止负反馈反应迅速,工作稳定等优点。     

热处理对离子束溅射Ta_2O_5薄膜特性的影响

利用离子束溅射沉积技术制备了Ta2O5薄膜,在100~600℃的大气氛围中对其进行热处理(步进温度为100℃),并对热处理后样品的光学常数(折射率、折射率非均匀性、消光系数和物理厚度)、应力、晶向和表面形貌进行了研究。研究显示,随着热处理温度增加,薄膜折射率整体呈下降趋势,折射率非均匀性和物理厚度呈增加趋势,结果有效地改善了薄膜的消光系数和应力,但薄膜的晶向和表面形貌均未出现明显的变化。结果表明:热处理可以有效改变薄膜特性,但需要根据Ta2O5薄膜具体应用综合选择最优的热处理温度。本文对离子束溅射Ta2O5薄膜的热处理参数选择具有指导意义。     

A magnetron sputtering system for the preparation of patterned thin films and in situ thin film electrical resistance measurements

We describe a versatile three gun magnetron sputtering system with a custom made sample holder for in situ electrical resistance measurements, both during film growth and ambient changes on film electrical properties. The sample holder allows for the preparation of patterned thin film structures, using up to five different shadow masks without breaking vacuum. We show how the system is used to monitor the electrical resistance of thin metallic films during growth and to study the thermodynamics of hydrogen uptake in metallic thin films. Furthermore, we demonstrate the growth of thin film capacitors, where patterned films are created using shadow masks.     

Structural and mechanical properties of (Cr,Ni) N single and gradient layer coatings deposited on mild steel by magnetron sputtering

Ternary single and gradient layer (Cr, Ni) N thin films were deposited on the mild steel substrate by unbalanced magnetron sputtering technique in order to evaluate mechanical properties for machine tools and automotive applications. Microstructure, chemical composition, surface morphology and phase analysis were carried out using field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, atomic force microscopy and X-ray diffraction, respectively. Both single and gradient layer of (Cr, Ni) N coatings show a significant increment in mechanical properties such as hardness, adhesion strength and surface roughness along with the reduction of friction coefficient. Mechanical tests revealed that the hardness of the gradient layer increased up to 3.1 times due to the formation of Cr₂N and Ni phase whereas single layer showed the least friction. Single layer CrNiN layer exhibited 27.2% less surface roughness (R_a) in comparison with gradient layer. High values of surface roughness, hardness, thickness and friction could be correlated with high film-to-substrate adhesion (L_c2) for the gradient layer.     

磁控溅射Ni56Mn27Ga17合金薄膜的光学反射特性研究

Ni-Mn-Ga磁性形状记忆合金薄膜是非常有用的多功能材料,为考察其光学反射特性,采用磁控溅射技术在单晶硅衬底上沉积了Ni56Mn27Ga17合金薄膜,并对其表面形貌和光学反射特性进行研究。研究结果表明,薄膜的表面粗糙度随退火温度的升高而增大;在300～800nm波长范围内,薄膜反射率均随波长的减小而降低,且薄膜整体谱线范围内的反射率随退火温度的升高而降低。     

Tribological characteristics of gold films deposited on metals by ion plating and vapor deposition

Recent work on the graded interface between an ion-plated film and a substrate is discussed as well as the friction and wear properties of ionplated gold. X-ray photoelectron spectroscopy, depth profiling and microhardness measurements were used to investigate the interface. The friction and wear properties of ion-plated and vapor-deposited gold films were studied both in an ultrahigh vacuum system to maximize adhesion and in oil to minimize adhesion. The results of the investigation indicate that the solubility of gold in the substrate material controls the depth of the graded interface. Thermal and chemical diffusion mechanisms are thought to be involved in the formation of the Au-Ni interface. In the Fe-Au graded inter- face, gold was slightly dispersed in the iron and formed only a physically bonded interface. The hardness of the gold film was influenced by the thickness and was also related to the composition gradient between the gold and the substrate. A graded Ni-Au interface exhibited the highest hardness because of an alloy hardening effect. The effects of film thickness on adhesion and friction were established. A minimum coefficient of friction was found in the thin film region. No graded interfaces were detected in this investigation between vapor-deposited gold films and substrates.     

Anti-oxidant mechanism of TiAlN/SiN decorative films on borosilicate glass by magnetron sputtering

The black TiAlN decorative film was prepared on the borosilicate glass by the magnetron sputtering in equipment with multiple vacuum chambers. The transparent SiN protective layer was deposited on the surface of the TiAlN film to keep the black color invariant at the high temperature. The structure of the TiAlN/SiN film was characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), and high-resolution transmission electron microscopy (HRTEM). The coating adhesion was measured by scratch tester. The TiAlN film has a columnar crystal structure with a thickness of 200 nm, and the top SiN layer is amorphous with a thickness of 100 nm. The coated borosilicate glass with the TiAlN/SiN films still retains the black color after oxidation at 600 °C in atmosphere. While the oxidation temperature elevates to 700 °C, the color of the TiAlN/SiN films begins to change. The top SiN layer plays a role as the barrier against oxygen diffusion into the inner TiAlN layer. The thin self-formed aluminum oxide layer was generated on the surface of the SiN layer and it contributes to the improvement of anti-oxidant property of the inner TiAlN layer. However, the thick self-formed aluminum oxide layer leads to the color change of the black TiAlN film. The thermal oxidation benefits the improvement of the adhesion for the TiAlN/SiN films with glass substrate.     

Tribological properties of nanostructured DLC coatings deposited by C60 ion beam

The frictional and wear characteristics of nanostructured DLC films were investigated. The coatings were deposited on silicon substrates by irradiation of a mass-separated C₆₀ ion beam with 5 keV of energy and a deposition temperature ranging from 100 to 450 °C. The effects of deposition temperature on the surface morphology, nano-structure, mechanical properties and tribological characteristics of the coatings were assessed. Results showed that deposition temperature strongly affects the nanostructure and surface morphology of the coatings. Coatings deposited at temperatures exceeding 350–400 °C exhibited an increase in surface roughness as well as compressive stress due to the formation of graphite, which led to a significant increase in the friction coefficient and wear rate. Coatings deposited at 300 °C showed the best tribological properties.     

柔性衬底直流磁控溅射ZnO基高性能透明导电薄膜的制备及性能研究

采用直流磁控溅射法,以柔性PET(聚对苯二甲酸乙二醇酯)为基底,通过参数优化以求在室温下制备高性能ZnO/Ag/ZnO多层薄膜。实验中,使用X射线衍射仪(XRD)、原子力显微镜(AFM)、紫外-可见分光光度计、四探针电阻测试仪等仪器分别对ZnO/Ag/ZnO多层薄膜的微观结构、表面形貌、透过率及方块电阻进行测试及表征。结果表明,随着Ag层厚度增加,薄膜方块电阻急剧下降,通过改变ZnO层厚度,可有效调节薄膜光学性能,随着ZnO层厚度增加,可见光区平均透过率先增大后减小。引入品质因子FTC作为评价指标可知,当依次沉积ZnO、Ag、ZnO厚度为50nm、8nm、50nm时,薄膜光电性能最佳,其在可见光平均透过率为82.3%、方块电阻为2.8Ω/、禁带宽度为3.332eV。