W-C-S-Mo复合薄膜的制备及力学和摩擦学性能

利用磁控溅射与磁过滤阴极真空电弧（MS/FCVA）复合沉积法，在不同偏压下在单晶Si基体上制备W-C-S-Mo四元复合薄膜；分析沉积偏压对薄膜纳米硬度、弹性模量和膜基结合力等力学性能的影响；在潮湿大气、真空环境下研究偏压对薄膜摩擦学性能的影响。结果表明，薄膜硬度、弹性模量和附着力随着沉积负偏压的增大呈现先增大后减小的趋势，在偏压-100 V时薄膜力学性能最好；负偏压-100 V下制备的W-C-S-Mo四元复合薄膜样品在潮湿大气和真空环境下均具有较好的摩擦学性能，拉曼测试发现，W-C-S-Mo复合薄膜在潮湿大气环境中的润滑作用主要由DLC提供，而在真空环境中薄膜中的软质相MoS2晶粒起润滑作用。     

沉积温度对脉冲真空弧源沉积类金刚石薄膜性能的影响

利用脉冲真空弧源沉积技术在Cr17Ni14Cu4不锈钢和Si(100)基体上制备了类金刚石(DLC)薄膜,研究了基体沉积温度对DLC薄膜的性能和结构的影响。研究表明,随着沉积温度由100 ℃提高到400 ℃,DLC薄膜中sp3 键质量分数减少,sp2键质量分数增多,薄膜复合硬度逐渐降低。当DLC薄膜沉积温度达到400 ℃时,薄膜中C原子主要以sp2键形式存在,与沉积温度为100 ℃时制备的DLC薄膜相比,薄膜复合硬度降低50%。DLC薄膜具有优异的耐磨性,摩擦因数低,随着沉积温度由100 ℃提高到400 ℃,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜耐磨性降低。沉积温度为100 ℃时,Cr17Ni14Cu4不锈钢表面沉积的DLC薄膜后,耐磨性大幅度提高。DLC薄膜与不锈钢基体结合牢固。     

过滤式阴极电弧沉积类金刚石薄膜的碳弧稳定性研究

介绍自行研制的一套过滤式阴极电弧沉积设备,并以石墨作为靶材进行类金刚石薄膜的沉积研究,碳弧本身的惰性限制了电弧的稳定性。电弧电压,磁场等对弧的稳定性有很大的作用。试验得到表面光滑的类金刚石薄膜,并对其进行了形貌分析。     

Direct-current cathodic vacuum arc system with magnetic-field mechanism for plasma stabilization

Filtered cathodic vacuum arc (FCVA) deposition is characterized by plasma beam directionality, plasma energy adjustment via substrate biasing, macroparticle filtering, and independent substrate temperature control. Between the two modes of FCVA deposition, namely, direct current (dc) and pulsed arc, the dc mode yields higher deposition rates than the pulsed mode. However, maintaining the dc arc discharge is challenging because of its inherent plasma instabilities. A system generating a special configuration of magnetic field that stabilizes the dc arc discharge during film deposition is presented. This magnetic field is also part of the out-of-plane magnetic filter used to focus the plasma beam and prevent macroparticle film contamination. The efficiency of the plasma-stabilizing magnetic-field mechanism is demonstrated by the deposition of amorphous carbon (a-C) films exhibiting significantly high hardness and tetrahedral carbon hybridization (sp3) contents higher than 70%. Such high-quality films cannot be produced by dc arc deposition without the plasma-stabilizing mechanism presented in this study.     

Nanometre scale mechanical properties of extremely thin diamond-like carbon films

Abstract

Extremely thin diamond-like carbon (DLC) films are deposited by the filtered cathodic vacuum arc (FCVA) and plasma chemical vapour deposition (p-CVD) methods. The target thicknesses of the extremely thin protective DLC films deposited on a Si (100) surface by FCVA and p-CVD are 0·1, 0·4, 0·8, 1·0, 2·0, 5·0 and 100·0 nm. Nanoindentation hardness and nanowear resistance are evaluated by atomic force microscopy (AFM). The nanoindentation hardnesses of 100 nm thick DLC films deposited by FCVA and p-CVD are 57 and 25 GPa respectively. The nanowear test by AFM clarifies the mechanical properties of extremely thin DLC films. The wear depths of 1 and 2 nm thick FCVA-DLC films are extremely shallow. The wear depths of the 1·0 and 2·0 nm thick p-CVD-DLC films exceed the film thicknesses after five sliding cycles. These results reveal differences in the wear resistance of extremely thin DLC films and the superior mechanical properties of FCVA-DLC thin films.     

Requirements of ultrathin carbon coatings for magnetic storage technology

Diamond-like carbon (DLC) is presently used as protective coating on disks, heads and sliders used in magnetic disk storage technology. The rapidly increasing storage density will soon require carbon films of only 2 nm thickness. Carbon films are now made by sputtering, but it is unlikely that this method can provide the continuous 2 nm films needed in future. This paper describes methods to produce thinner films, such as filtered cathodic vacuum arc (FCVA) and plasma enhanced chemical vapour deposition (PECVD) methods. Various characterisation methods such as Raman and X-ray reflectivity are described and compared.     

Load-carrying capacity evaluation of coating/substrate systems for hydrogen-free and hydrogenated diamond-like carbon films

Diamond-like carbon (DLC) coatings have shown excellent tribological properties in laboratory tests. The coatings have also been introduced to several practical applications. However, the functional reliability of the coatings is often weakened by adhesion and load-carrying capacity related problems. In this study the load-carrying capacity of the coating/substrate system has been evaluated. The DLC coatings were deposited on stainless steel, alumina and cemented carbide with two different deposition techniques: the tetrahedral amorphous carbon (ta-C) coatings were deposited by a pulsed vacuum arc discharge deposition method and the hydrogenated carbon (a-C:H) films by radio frequency (r.f.) plasma deposition method. The load-carrying capacity of the coated systems was evaluated using a scratch test, Rockwell C-indentation test and ball-on-disc test. The effect of substrate material, substrate hardness, coating type and coating thickness was studied. An increase in substrate hardness increased the load-carrying capacity for the coated systems, as expected. The two coating types exhibited different performance under load due to their different physical and mechanical properties. For the load-carrying capacity evaluations the ball-on-disc configuration was found to be most suitable. This revised version was published online in July 2006 with corrections to the Cover Date.     

脉冲离子镀技术镀制DLC薄膜附着力研究

从应用的角度讨论了脉冲电弧离子镀技术镀制类金刚石薄膜的附着力问题 ,指出了影响附着力的主要因素 ,提出了增加附着力的几种途径。     

Friction and wear behaviour of hard and superhard coatings at cryogenic temperatures

The work presents data on friction and wear behaviour of pin-on-disc pairs with superhard diamond-like carbon (DLC) coatings and hard coatings of zirconium nitride (ZrN) and titanium nitride (TiN) in liquid nitrogen with loads of 2.5 and 10 N and sliding speed of 0.06 m/s. It is shown that at cryogenic temperatures the friction coefficients of pairs of two types of DLC coatings obtained by vacuum-arc deposition of filtered high-speed carbon plasma fluxes depend to a great deal on the mechanical properties of the coatings defined by predominant sp² or sp³ hybridization of valence electrons. A friction coefficient of 0.76 was observed for friction pairs of superhard (90 GPa) DLC coatings having properties similar to those of diamond. For “softer” DLC coatings of 40 GPa and properties similar to those of graphite the friction coefficient shows lower values (0.24–0.48) dependent on normal load and counterbody material. The DLC coatings obtained by the filtered arc technology exhibit good wear resistance and have strong adhesion to the substrate under friction in liquid nitrogen. With a normal load of 10 N under cryogenic temperature a low wear rate (of the order of 7.2×10⁻⁴ nm/cycle) was found for superhard DLC coatings. The friction coefficient of pairs with hard ZrN and superhard DLC coatings on steel discs was revealed to be linearly dependent on the counterbody material hardness between 20 and 100 GPa. The hardness of the pin was varied by means of depositing TiN or DLC coatings and also by using high-hardness compounds (boron nitride and synthetic diamond). Proceeding this way can be promising since it offers the possibility of creating low-temperature junctions of required friction properties.     

Frictional properties of diamond-like carbon coated tool in dry intermittent machining of aluminum alloy 5052

In this study, an orthogonal intermittent machining test for aluminum alloy 5052 was conducted under dry conditions. By using cutting forces that were measured during the test, the frictional properties of a tool rake face were evaluated during intermittent machining for two types of diamond-like carbon (DLC)-coated tools and an uncoated carbide tool. DLC films used in the test were composed of tetrahedral amorphous carbon (ta-C) deposited by a filtered arc deposition process and hydrogenated amorphous carbon (a-C:H) deposited by a plasma-enhanced chemical vapor deposition process. The test results showed that the initial friction coefficients were approximately 0.8 for all tools. However, with increasing machining time, the friction coefficient of only the ta-C-coated tool decreased remarkably to a lower value of 0.3, whereas those of the a-C:H-coated tool and the uncoated carbide tool remained high. An electron probe micro analyzer (EPMA) analysis revealed an area where no aluminum adhered on the ta-C-coated tool rake face after intermittent machining. This area provided low frictional properties during intermittent machining. An X-ray photoelectron spectroscopy (XPS) analysis showed that the carbon bonding of the DLC film surface in this area had changed from the state before machining.     

EFFECT OF SURFACE ENERGY ON THE GROWTH OF DIAMOND-LIKE CARBON/AMORPHOUS SILICON FILMS ON VARIOUS SUBSTRATES

Diamond-like carbon/amorphous silicon bilayer films were deposited on SiO₂, Ge, and Ta₂O₅ substrates using a pulsed filtered cathodic arc (PFCA) system. Amorphous silicon (a-Si) layer was firstly deposited on three substrates using DC magnetron sputtering, then diamond-like carbon (DLC) film was deposited on a-Si layer via pulsed filtered cathodic arc. The thicknesses of a-Si layer and DLC film as monitored by in-situ ellipsometry during the film deposition were 7 and 10 nm, respectively. The surface energy of SiO₂, Ge, and Ta₂O₅ substrates was determined by measuring the contact angle of water on these substrates. It was found that the contact angles of water on SiO₂, Ge, and Ta₂O₅ substrates were 53°, 63°, and 75°, respectively. This result indicates that SiO₂ has the highest surface energy while Ta₂O₅ has the lowest surface energy. The thickness of the a-Si layer and DLC film was determined from the cross-section transmission electron microscopy (TEM) images. The thinnest a-Si layer of 5.64 nm was obtained from SiO₂ substrate which has the highest surface energy. The thickest a-Si layer of 6.97 nm was obtained from Ta₂O₅ corresponding to the lowest surface energy. This study shows that the thickness of the growth film strongly depends on the surface energy of the substrate. However, the DLC films deposited on each a-Si layer of three substrates have the same thickness approximately of 9.9 nm, because all of them were deposited on a-Si layers having the same surface energy.     

脉冲多弧离子源的研制

脉冲多弧离子源主要用来镀制类金刚石薄膜及金属、合金膜,研究了脉冲多弧离子源的引弧方法、放电的稳定性、离子源结构对镀膜均匀性的影响。在此基础上,研制了脉冲多弧离子源,利用该源镀制了类金刚石薄膜及镍铬铁合金渐变膜。经测试,膜层性能良好。     

脉冲磁过滤阴极弧技术制备类金刚石薄膜研究

介绍了弯曲电弧磁过滤设备,并利用脉冲磁过滤阴极真空电弧沉积技术,在高速钢基体上制备了DLC膜.对制得的DLC薄膜表面形貌、Raman光谱及纳米硬度和弹性模量等进行了测试.结果表明,脉冲磁过滤阴极电弧法制备的DLC膜具有优良的性能.拉曼光谱分析显示,制得的薄膜为非晶结构,具有明显的sp2和sp3键杂化结构,符合DLC膜的特征,基体负偏压为50 V时,沉积的DLC膜Raman光谱的ID/IG值最小,sp3键含量最高,纳米硬度和弹性模量值达到最高,分别为29.94 GPa和333.9 GPa.     

Determination of the composition and thickness of chromel and alumel thin films on different substrates by quantitative energy dispersive spectroscopy analysis

Thin films of two alloys (chromel and alumel), with thickness less than 100 nm, were obtained by plasma deposition technique, namely filtered cathodic vacuum arc (FCVA). The elemental analyses were performed by quantitative energy dispersive spectroscopy (EDS) microanalysis and Rutherford backscattering spectrometry (RBS). The applicability of EDS to such thin films as these was established by analysis of films deposited on substrates of different atomic numbers, specifically vitreous carbon, silicon, copper, and tin. We found that a substrate with atomic number similar to the mean atomic number of the film constituents is best for reliable EDS results, when compared to RBS. The compatibility between quantitative EDS measurements and RBS measurements, as well as comparison between the thin film elemental composition and the bulk material composition, was assessed by statistical analysis. Good consistency between EDS and RBS measurements was found for both chromel and alumel thin films when copper was used as substrate material. We observed severely overlapping peaks in the RBS output for the case of alumel films so that EDS analysis was crucial. We also compared thickness measurements determined by EDS and RBS, and we found good agreement for the case of alumel film on copper substrate, and 15% agreement for chromel film on copper substrate.     

磁头/磁盘表面保护膜及抗吸附分子膜研究

在中国国家自然科学基金重大项目《先进电子制造中的重要科学技术问题研究》资助下，针对2nm厚度的DLC薄膜的制备和磁头、磁盘间的吸附等问题，探索“磁头、磁盘表面润滑规律和超薄保护膜的生长机理及技术”，目标是寻找磁头、磁盘表面超薄DLC薄膜新的制备方法和制备工艺，发现超薄DLC保护膜的生长机理和生长极限，开发磁头表面抗吸附分子膜的制备技术。报告研究所取得的体系化理论成果。 为了制备厚度为2nm的超薄DLC薄膜，使用FCVA技术代替磁控溅射和CVD技术。通过优化制备参数，制备出厚度为2nm，表面粗糙度为0.128nm，并且连续均匀的DLC薄膜。探索基体形貌对薄膜生长模式的影响规律。发现在脉冲偏压幅值-100V、占空比20%条件下制备的薄膜性能最优     

ECR-CVD制备类金刚石碳膜的正交实验法研究

采用系统的正交实验法对ECR-CVD法沉积类金刚石碳膜(DLC)的优化工艺进行研究,并分析不同工艺参数对DLC膜性能的影响.共选择基片温度、H2流量、微波功率、直流偏压、脉冲偏压以及脉冲偏压占空比6个参数建立起6因素5水平的正交表,分别以薄膜摩擦因数、磨损率、显微硬度、拉曼谱中D峰与G峰的面积比ID/IG作为考察对象进行研究.极差分析表明,对不同的考察因素其优化工艺略有区别.在所选的参数范围内,脉冲偏压对所测量的DLC膜的性能影响最大.     

负偏压对含氢类金刚石薄膜性能的影响

为了解决类金刚石(DLC)薄膜与金属基材间的界面结合强度问题,本研究采用直流等离子体增强化学气相沉积(DC-PECVD)技术,以等时长、不同偏压条件在45钢基材上沉积复合DLC薄膜.采用扫描电镜、原子力显微镜观察薄膜形貌;采用拉曼光谱仪分析薄膜成分;采用涂层附着力自动划痕仪测定膜基结合强度.结果表明:制备偏压从-600...     

基于LM算法的无氢类金刚石薄膜喇曼高斯分解

介绍高斯分解及基于ＬＭ算法的数值计算方法，并对无氢类金刚石薄膜的喇曼光谱曲线进行了分解。结果表明，数值计算的收敛性较好，数值拟合的相关系数均大于９５％，完全可以用于类金刚石薄膜的微观结构分析。根据分解结果可知，随着偏压的增加，Ｄ带和Ｇ带的分布中心均向低频偏移，而Ｇ带和Ｄ带的半高宽之比呈逐渐增大趋势。这表明膜层中ｓｐ＾３键的含量不断提高，同时键的扭曲程度不断增大。     

无氢类金刚石薄膜的过滤式阴极电弧沉积

研制了一套过滤式阴极电弧沉积设备 ,并利用该设备成功地获得了类金刚石薄膜。扫描电镜分析表明 :获得的薄膜在硅基片上是光滑和致密的。喇曼光谱研究表明 ,这种薄膜是典型的无氢类金刚石薄膜。膜层的摩擦试验表明 :无氢类金刚石薄膜的摩擦系数较低 ,是一种理想的耐磨材料     

Microfrictional properties of diamond-like carbon films sliding against silicon, sapphire and steel

The low contact pressure characteristic of the microtribological regime relative to macro and nanosystems is suited for testing the microfrictional properties of different types of thin films. Motivated by macro as well as microsystem applications, this study investigates the microfrictional properties of different types of diamond-like carbon (DLC) films, prepared using low- and high-frequency plasma-assisted chemical vapor deposition (HF-PACVD) and the vacuum arc method. Testing was performed with a reciprocating precision microtribometer. Silicon, sapphire and steel balls were used as counterbodies. Friction-load curves suggest that, for applied forces in the μN to mN regime, two properties have a strong influence on the microfriction: first, the chemical composition plays a dominant role and second, the film roughness. With silicon and steel balls, the microfriction of hydrogen-free DLC films was greater than the hydrogen-containing films. With sapphire counterbodies, the results indicate that microfriction is inversely proportional to the film roughness. Also, for the films tested, microfriction was determined to be independent of the sliding velocity. For the force (pressure) regimes tested, mild wear was observed on silicon and some steel counterbodies, while no wear could be detected on any of the DLC films. These results illustrate the utility of implementing microtribological testing in comparative coating studies.