Properties of W/DLC/W-S-C composite films fabricated by magnetron sputtering

A kind of W/DLC/W-S-C composite film was fabricated by magnetron sputtering method.Effects of WSx content on the structure and the adhesion of the composite films were investigated.In addition,tribological behavior of the composite films was studied in the conditions of the ambient air and N2 gas atmosphere by ball-on-disk tester.The results indicate that the composite films show dense and amorphous microstructure.The WCx and WSx compounds are found in amorphous diamond like carbon matrix in the top layers of W-S-C.A proper WSx content is beneficial for improving the adhesion of the composite films.In air atmosphere,the composite films with high C content have better wear resistance and the friction coefficients range from 0.15 to 0.25.In N2 condition,high WSx content is benefit for the wear resistance and the friction coefficients of the composite films range from 0.03 to 0.1.

DLC基纳米多层膜摩擦学性能的研究进展与展望

类金刚石(DLC)薄膜是一种良好的固体润滑剂,能够有效延长机械零件、工具的使用寿命。DLC基纳米多层薄膜的设计是耐磨薄膜领域的一项研究热点,薄膜中不同组分层具备不同的物理化学性能组合,能从多个角度(如高温、硬度、润滑)进行设计来提升薄膜力学性能、摩擦学性能以及耐腐蚀性能等。综述了DLC多层薄膜的设计目的与研究进展,以金属/DLC基纳米多层膜、金属氮化物/DLC基纳米多层膜、金属硫化物/DLC基纳米多层膜以及其他DLC基纳米多层膜为主,对早期研究成果及现在的研究方向进行了概述。介绍了以上几种DLC基纳米多层膜的现有设计思路(形成纳米晶/非晶复合结构、软/硬交替沉积,诱导转移膜形成,实现非公度接触)。随后对摩擦机理进行了分析总结:1)层与层间形成特殊过渡层,提高了结合力;2)软/硬的多层交替设计,可以抵抗应力松弛和裂纹偏转;3)高接触应力和催化作用下诱导DLC中的sp3向sp2转化,形成高度有序的转移膜,从而实现非公度接触。最后对DLC基纳米多层膜的未来发展进行了展望。

Characterization and analysis of DLC films with different thickness deposited by RF magnetron PECVD

Diamond-like carbon (DLC) films have excellent mechanical and chemical properties similar to those of crystalline diamond giving them wide applications as protective coatings. So far, a variety of methods are employed to deposit DLC films. In this study, DLC films with different thicknesses were deposited on Si and glass substrates using RF magnetron PECVD method with C 4 H 10 as carbon source. The bonding microstructure, surface morphology and tribological properties at different growing stages of the DLC films were tested. Raman spectra were deconvoluted into D peak at about 1370 cm 1 and G peak around 1590 cm 1 , indicating typical features of the DLC films. A linear relationship between the film thickness and the deposition time was found, revealing that the required film thickness may be obtained by the appropriate tune of the deposition time. The concentration of sp 3 and sp 2 carbon atoms in the DLC films was measured by XPS spectra. As the films grew, the sp 3 carbon atoms decreased while sp 2 atoms increased. Surface morphology of the DLC films clearly showed that the films were composed of spherical carbon clusters, which tended to congregate as the deposition time increased. The friction coefficient of the films was very low and an increase was also found with the increase of film thickness corresponding to the results of XPS spectra. The scratch test proved that there was good bonding between the DLC films and the substrates.

Preparation and Characterization of DLC Films by Twinned ECR Microwave Plasma Enhanced CVD for Microelectromechanical Systems (MEMS) Applications

Diamond-like carbon (DLC) films have recently been pursued as the protection of MEMS against their friction and wear.Plasma enhanced chemical vapor deposition (PECVD) technique is very attractive to prepare DLC coating for MEMS.This paper describes the preparation of DLC films using twinned electron cyclotron resonance (ECR) microwave PECVD process.Raman spectra confirmed the DLC characteristics of the films.Fourier-transform infrared (FT-IR)characterization indicates the carbon is bonded in the form sp~3 and sp~2 with hydrogen participating in bonding.The surface roughness of the films is as low as approximately (0.093)nm measured with an atomic force microscope.A CERT microtribometer system is employed to obtain information about the scratch resistance,friction properties,and sliding wear resistance of the films.The results show the deposited DLC films have low friction and good scratch/wear resistance properties.

化学气相沉积Cr/DLC薄膜对Mg-Gd-Y合金耐蚀性能的改善

Mg-Gd-Y合金作为一种优秀工程材料在石油天然气勘探开发中具有广泛应用。为了改善其在井下工作服役时的耐蚀性能,研究了以Cr为过渡层的类金刚石薄膜(DLC)对Mg-Gd-Y合金耐蚀性能的影响。采用等离子体增强化学气相沉积(PECVD)法制备了以Cr元素为过渡层的类金刚石薄膜,采用拉曼光谱分析DLC膜层的碳结构类型,采用3.5%(质量分数)NaCl盐雾腐蚀试验、电化学极化测试及接触角测试评价了试样的耐蚀性能,采用SEM分析了试样腐蚀前后的表面形貌及断面形貌。结果表明:由拉曼光谱检测数据计算得出,Cr/DLC薄膜的I_D/I_G值为0.64,说明膜层中sp~3杂化键所占比例较多,且组织致密,因此Cr/DLC薄膜在3.5%NaCl溶液中的腐蚀倾向和腐蚀速率降低。Cr/DLC薄膜有效提高了镁合金基体的耐蚀能力。

Ti-DLC薄膜压阻性能及载流子输运行为研究

围绕压阻传感器领域对高性能类金刚石(Diamond Like Carbon,DLC)薄膜压阻敏感材料的需求,针对金属掺杂DLC存在的载流子输运行为和实际多工况(如温度、湿度等)下压阻性能不明的问题,本工作以Ti-石墨复合拼接靶为靶材,采用高功率脉冲磁控溅射技术,高通量制备出4种Ti含量(原子分数为0.43%~4.11%)的Ti掺杂类金刚石(Ti-DLC)薄膜,研究了Ti含量对薄膜组分结构、电学性能、变湿度环境下压阻性能的影响规律。结果表明:Ti含量(原子分数)在0.43%~4.11%范围内,掺杂Ti原子均以固溶形式均匀镶嵌于非晶碳网络中,Ti-DLC薄膜电学行为表现为典型半导体特性,在200~350 K温度范围内,薄膜电阻率均随温度升高而降低。载流子传导机制在200~270 K内为Mott型三维变程跳跃传导,在270~350 K范围内则为热激活传导。Ti-DLC薄膜压阻系数(Gauge Factor,GF)最大值为95.1,在20%~80%相对湿度范围内,所有样品GF均随湿度增加而增大,这可能是引入的固溶Ti原子缩短了导电相之间的平均距离,同时吸附表面水分子导致电阻变化。

STUDY ON COMPOSITION, MICROSTRUCTURE AND HARDNESS OF DLC FILMS BY VCAD

DLC super-hard films have been deposited on the substrates of single crystalline Si, pure Ti and stainless steel 18-8 by a method of vacuum cathode arc deposition (VCAD). The composition, microstructure and micro-hardness of the films have been studied in this paper. The results indicate that hardness of the DLC films is different on the different substrates. Hardness of the films increases with decreasing in surface roughness of the films. The maximum value of micro-hardness belongs to the DLC films deposited under the hydrogen pressure of 0.35Pa and the negative bias of 100V.

Plasma Diagnosis for Microwave ECR Plasma Enhanced Sputtering Deposition of DLC Films

Application of the Langmuir probe in plasma circumstance for deposition of diamond-like carbon （DLC） thin films usually faces the problem of rapid failure of the probe due to surface insulative coating. In this paper, we circumvent the problem by using the floating harmonic probe technique. In the real circumstance of DLC film deposition, the floating harmonic probe worked reliably over 3 hours, correctly indicating the ion density and electron temperature. The technique was practically used to measure the ion density and electron temperature in DLC film deposition processes using the microwave ECR plasma enhanced sputtering. Combined with the Raman spectroscopic characterization of the films, the conditions for deposition of DLC films were investigated.

钽掺杂对多层Ta-DLC薄膜摩擦及腐蚀行为的影响

目的解决316L不锈钢在苛刻海洋环境中易磨损、易腐蚀的问题。方法采用中频磁控溅射技术在316L不锈钢上沉积了Ta/TaN/TaCN/Ta-DLC薄膜。通过扫描电子显微镜、拉曼光谱、X射线光电子能谱、X射线衍射、纳米压痕、往复摩擦磨损试验和电化学测试等手段,重点研究了DLC膜层中Ta元素掺杂含量对薄膜结构、组成成分、力学性能、摩擦学性能和耐腐蚀性能的影响规律。结果随着Ta元素含量(原子数分数)从2.04%增到4.16%,薄膜中的sp^(3)键含量呈现先升高后降低的趋势,当Ta原子数分数为3.60%时,薄膜中sp3键含量最高,且薄膜的硬度及弹性模量达到最大,分别为7.01 GPa和157.87 GPa。随着Ta元素含量的增加,薄膜的平均摩擦因数逐渐减小,在4.16%(原子数分数)时达到最小0.21。Ta元素含量对薄膜的结合力影响较小,且所有薄膜结合力总体在10 N左右。当Ta原子数分数为3.60%时,薄膜的腐蚀电流密度及钝化电流密度最小,分别为0.006μA/cm^(2)和0.63μA/cm^(2),比其他薄膜的低1~2个数量级,并且薄膜电阻及电荷转移电阻最大,展现出最为优异的耐腐蚀性能。结论Ta元素的掺杂提高了薄膜的耐摩擦性能,且适当的Ta元素掺杂能够提高Ta/TaN/TaCN/Ta-DLC薄膜的耐磨耐蚀性能。

Influence of nitrogen gas on structure and properties of DLC films prepared by XeCl pulsed laser deposition

Diamond-like carbon (DLC) films were prepared by PLD process using 308 nm(XeCl) laser beam with high power (500 W) and high frequency(300 Hz). The effects of nitrogen pressure on the structure and properties of the DLC films under such extremely high power and repetition rate were studied. The results indicate that the microstructures of the films are varied from amorphous carbon to graphitized carbon in long-order with the increase of N2 pressure, and the optical properties of the films are deteriorated as compared to that of DLC films without nitrogen.

Mechanical Properties of Composite SiNx/DLC Films Prepared by Filtered Cathodic Arc of Graphite Incorporated with RF Sputtering of Silicon Nitride

Composite SiNx/DLC films were deposited on Si substrate by RF magnetron sputtering of silicon nitride (Si3N4) target simultaneously with filtered cathode arc (FCA) of graphite. The RF power was fixed at 100 W whereas the arc currents of FCA were 20, 40, 60 and 80 A. The effects of arc current on the structure, surface roughness, density and mechanical properties of SiNx/DLC films were investigated. The results show that the arc current in the studied range has effect on the structure, surface roughness, density and mechanical properties of composite SiNx/DLC films. The composite SiNx/DLC films show the sp3 content between 53.5% and 66.7%, density between 2.54 and2.98 g/cm3, stress between 1.7 and 2.2 GPa, and hardness between 35 and 51 GPa. Furthermore, it was found that the density, stress and hardness correlate linearly with the sp3 content for composite SiNx/DLC films.

Composition and structure of Ti-C/DLC graded composite films

The Ti C→DLC gradient composite films were characterized systematically. The elemental depth profile and elemental chemical state evolution were determined by X ray photoelectron spectroscopy (XPS). The transmission electron microscope (TEM) and high resolution transmission electron microscopy (HRTEM) were used to study the structure of interfacial zone between DLC film and Ti C layers. Results show that there are composition transition zone between DLC film and either Ti C layer or steel substrate on condition that pre deposited Ti layers on the steel substrate then plasma based bias deposited DLC films. In Ti C graded layer, the chemical state of titanium and carbon are changed gradually. The structures of zone in Ti C layer near the DLC film is consisted of random oriented nanocrystallines TiC dispersed in amorphous DLC matrix. The structure of the zone between DLC film and Ti C graded layer is gradually changed too.

Effects of fragments on W-DLC films properties under boundary lubrication condition in the friction system

Abstract Effects of film fragments in the friction system on friction and wear properties of tungsten doped diamond-like carbon films （W-DLC） were studied in the condition of boundary lubrication. It could be observed that the average friction coefficient was increased after introducing film fragments into the friction system, where these film fragments can accelerate the breaking of the extreme thin oil film which could separate two friction surfaces when the system is under boundary lubrication conditions. The increasing friction load can accelerate the friction ehenfieal reaction on the friction interface and lead to the crushing effect on film fragments, which decreased the friction coefficient of friction system. It was also found that the wear width, depth, and volume of the film increased by introducing film fragments and applying great load.

不锈钢喷丝头表面镀DLC膜可行性探讨

为了提升化纤纺丝用喷丝头质量,介绍金铂合金、钽、不锈钢3种材质化纤喷丝头的优缺点;以SUS316L型不锈钢制作的PY35-2050-0.075型喷丝头为例,通过盐雾试验以及酸性溶液浸泡试验,对比分析其镀DLC膜前后的性能、质量及表面微观形貌变化。指出:以Cr+WC作为中间过渡层,能提高气相沉积DLC膜与不锈钢喷丝头基体的结合强度;镀DLC膜不锈钢喷丝头的硬度可达2000 HV,强度和耐酸碱腐蚀性均优于普通不锈钢喷丝头,使用寿命长,更适用于高温、高压以及酸碱腐蚀的纺丝环境。

Field Emission Properties of Nano-DLC Films Prepared on Cu Substrates by Pulsed Laser Deposition

Nano-diamond like carbon（DLC） thin films were prepared on fused silica and Cu substrates by the pulsed-laser deposition technique with different laser intensities. Step-measurement, atomic force microscope（AFM）, UV-VIS-NIR transmittance spectroscopy and Raman spectroscopy were used to characterize the films. It was shown that the deposition rate increases with the laser intensity, and the films prepared under different laser intensities show different transparency. Raman measurement showed that the content of sp^3 of the Nano-DLC thin films decreases with the laser intensity. The field emission properties of the Nano-DLC thin films on Cu substrates were studied by the conventional diode method, which showed that the turn-on field increases and the current density decreases with sp^3 content in the films. A lower turn-on field of 6 V/um and a higher current density of 1 uA/cm^2 were obtained for Nano-DLC thin films on Cu substrate.

非平衡磁控溅射制备Cr掺杂DLC复合薄膜的高温摩擦学性能

元素掺杂是提升DLC薄膜摩擦学性能和耐温性能的重要途径。采用直流磁控溅射技术在304不锈钢基体表面沉积了含氢DLC薄膜,同时利用射频磁控溅射技术完成Cr元素的掺杂,研究Cr元素掺杂对DLC薄膜的力学性能及摩擦学性能的影响。采用纳米压痕仪测试薄膜硬度并利用划痕试验测试膜基结合力,采用拉曼光谱分析薄膜sp2和sp3键含量的变化和转移膜的生成。采用UMT多功能摩擦磨损试验机评价薄膜在常温和高温环境下的摩擦磨损性能,并利用扫描电镜观察磨损表面,分析其磨损机制。结果表明,Cr元素掺杂会显著提高薄膜的膜基结合力,但会使薄膜硬度有一定的下降。常温摩擦学性能测试显示,DLC薄膜的摩擦因数随着Cr含量的增加呈现出先下降后上升的趋势,在Cr质量分数为3.34%时达到最低;但薄膜的磨损率随Cr含量的增加略有升高。高温摩擦学性能测试表明,Cr元素掺杂显著改善了DLC薄膜的高温摩擦学性能,未掺杂的DLC在150℃以上摩擦时会失效,Cr元素掺杂使薄膜在250℃下也能保持较低的摩擦因数和较长的抗磨寿命。Cr元素的加入能够提高DLC薄膜的膜基结合力,降低摩擦因数,并提高薄膜的高温摩擦学性能,这主要是因为Cr元素掺杂促使薄膜结构发生转变,同时Cr的氧化物也起到了一定的保护作用。

Tribological Characteristic of Diamond-like Carbon Films Investigated by Lateral Force Microscope

Tribological characteristic of different thick diamond-like carbon (DLC) films was studied. A geometrical method was applied to calibrate the cantilever spring constant and to calculate the normal and lateral forces, respectively. Experimental results show that the lateral force under different applied loads is proportional to the normal force for the DLC films with the thickness of 153.4nm and 64.9nm. However, for the thickness of 4.48nm and 2.78nm DLC films, lateral force is nonlinear to normal force, which is opposed to the Amonton's law.The single asperity regime and the DMT model were put forward to predict the possible nanotribological mechanism between the probe and DLC film.

Tribological Properties of DLC Film Prepared by C^+ Ion Beam-assisted Deposition (IBAD)

C ^＋ ion beam-assisted deposition was utilized to prepare deposit diamond-like carbon （ DLC ） film. With the help of a series of experiments such as Raman spectroscopy, FT-IR spectroscopy, AFM and nanoindentation , the DLC film has been recognized as hydrogenated DLC film and its tribologicul properties have been evaluated. The bull-on-disc testing results show that the hardness and the tribologicul properties of the DLC film produced by C^ ＋ ion beam- assisted deposition are improved significantly. DLC film produced by C ^＋ ion beam- assisted deposition is positive to have a prosperous tribologicul application in the near future.

Microstructure and Mechanical Property of Magnetron Sputtering Deposited DLC Film

A diamond-like carbon（DLC） film was deposited on YT14 substrate using magnetron sputtering（MS）. The surface morphologies, roughness and bonding spectra of obtained film were characterized using scanning electron microscopy（SEM）, atomic force microscopy（AFM）, and X-ray photoelectron spectroscopy（XPS）, respectively, and its mechanical property and bonding strength were measured using a nanoindentation and scratch tester, respectively. The results show that the C-enriched DLC film exhibits a denser microstructure and smoother surface with lower surface roughness of 21.8 nm. The ratio of C sp2 at 284.4 e V that corresponds to the diamond（111） and the C sp3 at 285.3 e V that corresponds to the diamond（220） plane for the as-received film is 0.36： 0.64, showing that the C sp3 has the high content. The hardness and Young＇s modulus of DLC film by nanoindentation are 8.534 41 and 142.158 1 GPa, respectively, and the corresponding bonding strength is 74.55 N by scratch test.

橡胶表面粗糙度对DLC薄膜摩擦学性能的影响

目的探究三元乙丙橡胶(EPDM)表面粗糙度对DLC薄膜和Cr/DLC的微观结构、附着力、摩擦学性能的影响,并阐明Cr中间层对橡胶表面DLC薄膜的作用。方法使用砂纸打磨EPDM橡胶得到不同的表面粗糙度。采用非平衡磁控溅射技术在不同粗糙度的橡胶基体表面沉积无中间层的类金刚石碳基薄膜(DLC)及有Cr中间层的类金刚石碳基薄膜(Cr/DLC)。使用二维轮廓仪获得基体及薄膜的表面粗糙度,通过扫描电子显微镜以及拉曼光谱对薄膜的表面形貌和结构成分进行分析,并采用X切割试验和摩擦磨损试验分别评估DLC薄膜的附着力和摩擦学性能。结果基体表面粗糙度对薄膜的微观结构没有显著影响,但却对薄膜附着力以及摩擦学性能有较大的影响。薄膜附着力随着基体粗糙度的增加呈现先增大后减小的趋势,当基体表面粗糙度为1100 nm时,DLC薄膜具有最强的附着力和最佳的摩擦学性能。此外,Cr中间层的引入对提高薄膜附着力和承载能力起到了积极的作用。结论适当增加基体表面粗糙度可以增强DLC薄膜的附着力,改善薄膜的摩擦学性能。Cr中间层可以提高薄膜的承载能力,从而提高薄膜的耐磨性。