CoCrMo合金表面掺金属类金刚石薄膜的摩擦学性能

采用非平衡磁控溅射结合阳极型气体离子源技术在CoCrMo合金表面制备掺钨类金刚石薄膜(WDLC)和掺钛类金刚石薄膜(Ti-DLC)。利用努氏显微硬度计、结合力划痕仪、摩擦磨损试验机、表面形貌仪和洛氏硬度计表征膜层的力学性能,并用扫描电镜分析磨损形貌,探讨薄膜磨损机理。结果表明:所制备的2种薄膜均具有典型的DLC薄膜特征,W-DLC薄膜的硬度、结合力和摩擦磨损性能均优于Ti-DLC薄膜,更适合于CoCrMo合金的表面强化处理;CoCrMo合金的磨损机制主要为粘着磨损和磨粒磨损,而Ti-DLC/CoCrMo和W-DLC/CoCrMo的磨损机制以滑动磨损为主伴随极少量的磨粒磨损;经DLC薄膜处理,摩擦因数从CoCrMo合金的0.578降低到0.2以下,磨损率也降低了2个数量级,大幅度地提高了CoCrMo合金的摩擦磨损性能。     

DLC and UHMWPE as hard/soft composite film on Si for improved tribological performance

The main purpose of this study is to explore the advantages of using a composite thin film of ultra high molecular weight polyethylene (UHMWPE) on a hard diamond like carbon (DLC) coating deposited on Si, for high wear life and low coefficient of friction. The experiments are carried out using a ball-on-disc tribometer at a constant linear speed of 0.052 m/s. A 4 mm diameter silicon nitride ball with a normal load of 40 mN is used as the counterface. The tribological results are discussed on the basis of hardness, elastic modulus, contact area, contact pressure and optical images of surface films. As a result of higher load carrying capacity (high hardness and elastic modulus), the wear life of Si/DLC/UHMWPE coated layer is approximately five times greater than that of Si/UHMWPE. Looking at the film thickness effect, UHMWPE film shows maximum wear resistance when the film is of optimum thickness (6.2 μm-12.3 μm) on DLC. Wear mechanisms of different UHMWPE thicknesses for Si/DLC/UHMWPE film are explained using optical microscopy of worn surfaces. Further, the use of perfluoropolyether (PFPE) ultra-thin film as the top layer on the composite coatings reduces the coefficient of friction to very low values (0.06-0.07) and increases the wear life of the films by several folds.     

类金刚石薄膜在人工关节摩擦配副表面改性的应用

关节置换术是目前治疗关节疾病最直接、有效的手段,随着国民经济的增长,人工关节在我国的需求量不断增加。介绍了常见人工关节的类型及特点,以及目前用于提高人工关节摩擦副表面耐磨损性及耐腐蚀性的方法,通过比较发现,类金刚石（DLC）薄膜在提高人工关节耐磨损、耐腐蚀性能方面具有更好的应用前景。阐述了DLC薄膜结构、性能及其制备方法,并结合目前DLC薄膜在人工关节摩擦配副表面改性中应用所面临的主要问题,介绍了目前用于降低DLC薄膜内应力、增加DLC薄膜/基体结合力的方法。最后,针对 DLC 薄膜应用于人工关节摩擦配副表面改性中存在的缝隙腐蚀及结合失效问题,并结合人工关节体内服役环境特点,提出了利用金属离子催化人工关节摩擦配副表面吸附蛋白的变性、分解,形成致密生物薄膜,对DLC薄膜的磨痕和缺陷进行修复的思想,展望了新型DLC薄膜在人工关节表面改性中的应用前景。     

Tribological characterization of surface modified UHMWPE against DLC-coated Co–Cr–Mo

The generation of wear particles from the ultra-high molecular weight polyethylene (UHMWPE) counter-face of Co–Cr–Mo/UHMWPE sliding pair is relatively high. These polyethylene wear particles lead to osteolysis and that result in the failure of the implant made with the Co–Cr–Mo/UHMWPE sliding pair. Hence, an investigation has been carried out to enhance the wear resistance of UHMWPE by surface modification of one or either of the sliding surfaces. Tribological characterizations were carried out on good quality diamond-like carbon (DLC) coatings prepared on UHMWPE with and without prior C-ion implantation by filtered cathodic vacuum arc (FCVA) technique in conjunction with high substrate pulse biasing, sliding against uncoated and DLC-coated Co–Cr–Mo.

The evaluations are categorized into two groups: (1) unmodified and DLC-coated UHMWPE with and without prior carbon implantation sliding against uncoated Co–Cr–Mo, (2) DLC-coated UHMWPE with and without prior carbon implantation sliding against DLC-coated Co–Cr–Mo. The study reveals that by coating the UHMWPE with DLC coating protects the UHMWPE surface. However, the DLC coating causes severe Co–Cr–Mo wear. Coating both the sliding surfaces with DLC coating reduces the wear rates of the sliding surfaces to a greater extent. The DLC-coated UHMWPE with prior carbon implantation did not show any superior behaviour over that without prior carbon implantation.     

Study on Tribological Properties of CoCrMo Alloys against Metals and Ceramics as Bearing Materials for Artificial Cervical Disc

CoCrMo alloys are believed to be a kind of potential material for artificial cervical disc. However, the tribological properties of CoCrMo alloys against different metals and ceramics are not systematically studied. In this study, the tribological behaviors of CoCrMo alloys against metals (316L, Ti6Al4V) and ceramics (Si₃N₄, ZrO₂) were focused under dry friction and 25 wt.% newborn calf serum (NCS)-lubricated conditions using a ball-on-disc apparatus under reciprocating motion. The microstructure, composition and hardness of CoCrMo alloys were characterized using x-ray diffraction, scanning electron microscopy (SEM) and hardness testers, respectively. The contact angles of the CoCrMo alloys with deionized water and 25 wt.% NCS were measured by the OCA contact angle measuring instrument. The maximum wear width, wear depth and wear volume were measured by three-dimensional white light interference. The morphology and the EDX analysis of the wear marks on CoCrMo alloys were examined by SEM to determine the basic mechanism of friction and wear. The dominant wear mechanism in dry friction for CoCrMo alloys against all pairings was severe abrasive wear, accompanied with a lot of material transfer. Under 25 wt.% NCS-lubricated condition, the wear mechanism for CoCrMo alloys against ceramics (Si₃N₄, ZrO₂) was also mainly severe abrasive wear. However, severe abrasive wear and electrochemical corrosion occurred for the CoCrMo-316L pairing under lubrication. Severe abrasive wear, adhesive wear and electrochemical corrosion occurred for the CoCrMo-Ti6Al4V pairing under lubrication. According to the results, the tribological properties of CoCrMo alloys against ceramics were better than those against metals. The CoCrMo-ZrO₂ pairing displayed the best tribological behaviors and could be taken as a potential candidate bearing material for artificial cervical disc.     

Effect of N-ion implantation and diamond-like carbon coating on fretting wear behaviors of Ti6Al7Nb in artificial saliva

The tribology behaviors of Ti6Al7Nb, its alloy with N-ion implantation, and its alloy with diamond-like carbon (DLC) coating were investigated in artificial saliva. Fretting wear tests of untreated, N-ion implanted and DLC coated Ti6Al7Nb alloys plate against a Si₃N₄ ball were carried out on a reciprocating sliding fretting wear test rig. Based on the analysis of X-ray diffraction, Raman spectroscopy, 3-D profiler, SEM morphologies and frictional kinetics behavior analysis, the damage behavior of surface modification layer was discussed in detail. The results indicated that the fretting wear behavior of Ti6Al7Nb alloy with N-ion implantation was increased with the dose increase of the implanted nitrogen ions. Moreover, the DLC-coated Ti6Al7Nb alloy with low ion implantation could improve the fretting wear behavior greatly. In addition, the Ti6Al7Nb with DLC coating had better corrosion resistance due to the special compact structure. All results suggested that the Ti6Al7Nb with DLC coating had better wear resistance than that with N-ion implantation in artificial saliva.     

Microstructural, mechanical and tribological properties of tungsten-gradually doped diamond-like carbon films with functionally graded interlayers

A series of tungsten-gradually doped diamond-like carbon (DLC) films with functionally graded interlayer were prepared using a hybrid technique of vacuum cathodic arc/magnetron sputtering/ion beam deposition. With ‘compositionally graded coating’ concept, the deposition of wear-resistant carbon-based films with excellent adhesion to metallic substrate was realized. In the films, a functionally graded interlayer with layer sequence of Cr/CrN/CrNC/CrC/WC was first deposited onto the substrate, and then, a DLC layer doped with gradually decreasing content of W was coated on. The W concentration gradient along depth of the film was tailored by adjusting the W target current and deposition time. The characterized results indicate that the microstructural, mechanical and tribological properties of these films show a significant dependence on the W concentration gradient. A high fraction of W atom in carbon matrix can promote the formation of sp² sites and WC_1 − x nanoparticles. Applying this coating concept, strongly adherent carbon films with critical load exceeding 100 N in scratch test were obtained, and no fractures or delaminations were observed at the end of the scratched trace. The hardness was found to vary from 13.28 to 32.13 GPa with increasing W concentration. These films also presented excellent tribological properties, especially significantly low wear rate under dry sliding condition against Si₃N₄ ball. The optimum wear performance with friction coefficient of 0.19 and wear rate of 8.36 × 10⁻⁷ mm³/Nm was achieved for the tungsten-gradually doped DLC film with a graded W concentration ranging from 52.5% to 17.8%. This compositionally graded coating system might be a potentially promising candidate for wear-resistant carbon-based films in the demanding tribological applications.     

类金刚石薄膜改性钛合金的扭动摩擦磨损特性

以Ti6Al4V合金、类金刚石薄膜(DLC膜)改性Ti6Al4V合金分别与超高分子量聚乙烯(UHMWPE)配副,模拟颈椎间盘的轴向旋转运动,并在改装后的多自由度磨损试验机上进行扭动摩擦试验。结果表明:随着循环周次的增加,两对摩擦副均呈现出摩擦扭转力矩、摩擦耗散能、磨损量相应增大的趋势。与Ti6Al4V合金相比,DLC薄膜改性后的Ti6Al4V合金摩擦副接触界面间摩擦扭转力矩降低了51.6%、摩擦耗散能降低了48%,进入完全滑移状态的时间缩短,具有更好的耐磨性。Ti6Al4V合金的磨损机制表现为严重的磨粒磨损,经DLC薄膜改性后的钛合金的磨损形式以应力集中产生的脆性剥落为主。DLC薄膜增大了对磨副UHMWPE的磨损,UHMWPE的磨损机制是粘着磨损和磨粒磨损综合作用的结果。     

类金刚石碳膜的研究进展

从类金刚石碳膜作为耐磨薄膜的角度出发，综述了近年来类金刚石碳膜(DLC)结构、沉积技术、沉积机理和性能方面的相关研究进展。介绍了DLC的相结构、过滤阴极真空弧(FCVA)、类金刚石碳膜的沉积机理及主要工艺影响因素，同时指出了存在的问题及研究发展趋势。     

Tribological properties of diamond-like carbon coatings prepared by anode layer source and magnetron sputtering

In this work we studied the tribological properties of DLC coatings prepared by two deposition techniques. The emphasis was given on double layer Cr/DLC coatings deposited by a closed drift ion beam technique (anode layer source, ALS) with C₂H₂ and N₂ carrier gases. For comparison, the same types of substrates were coated by unbalanced magnetron sputtering in the CemeCon CC800/9 deposition system. Pin-on-disk experiments showed that the DLC coatings possess excellent wear resistance (wear rate down to 12 μm³/Nm) and also low values of coefficient of friction (down to 0.055). The presence of a carbon transfer layer, which is mainly responsible for good tribological properties, was observed on the wear scars of ball surfaces by optical microscopy. In addition, we measured the Vickers microhardness (1000–3100 HV), performed the scratch test (L_C in the range 40–100 N) and Rockwell indentation test to measure adhesion. Coating surface has been analyzed by atomic force microscopy (AFM) and by profilometry.     

Cr基过渡层对钛合金表面类金刚石薄膜摩擦学性能的影响

采用磁控溅射技术在钛合金(Ti6Al4V)表面制备Cr、Cr/Cr N和Cr/Cr N/Cr NC过渡层结构的类金刚石(DLC)薄膜。采用扫描电子显微镜、拉曼光谱仪与原子力显微镜分析薄膜的结构和表面形貌,利用纳米压痕仪、薄膜内应力测试仪、划痕测试仪、摩擦试验机和二维轮廓仪研究薄膜的硬度、内应力、结合力和摩擦磨损性能。结果表明:随着Cr基梯度过渡层的引入,DLC薄膜的内应力逐渐下降,结合力逐渐上升。Cr/Cr N/Cr NC/DLC薄膜具有优异减摩抗磨性能,摩擦因数和磨损率低至0.09±0.02和(1.89±0.15)×10-7 mm3/N·m。试验结果对钛合金表面高性能DLC薄膜制备及应用具有一定的参考价值和指导意义。     

类金刚石膜对CoCrMo合金摩擦性能的影响

目的研究类金刚石膜(DLC)在不同工况条件下的摩擦性能。方法使用磁控溅射技术,在CoCrMo合金表面沉积掺杂Cr元素的DLC薄膜。通过X射线衍射能谱和拉曼光谱对DLC膜表面的化学成分进行分析,采用扫描电镜(SEM)和原子力显微镜(AFM)观察DLC膜的表面形貌,借助摩擦试验仪测试DLC膜在不同工况条件下的摩擦性能。结果薄膜表面呈现颗粒状结构,且薄膜表面粗糙度在10 nm左右,物相分析表明,DLC薄膜为非晶化结构。在牛血清白蛋白(BSA)和NaCl溶液润滑条件下,DLC/CoCrMo摩擦副的平均摩擦系数(COF)分别趋于0.08,磨损区域存在少量的刮痕;而在干摩擦条件下,摩擦系数曲线表现出由高到低的变化趋势,平均摩擦系数约为0.21,同时在销磨损表面能观察到石墨化转移层。当接触压力为1 MPa时,平均摩擦系数约为0.10;接触压力增加至8 MPa时,平均摩擦系数约为0.08。结论润滑条件下,DLC膜表面悬键被钝化,减小其与配副表面之间的相互作用力,因此摩擦系数较低;干摩擦条件下,石墨化转移层充当固体润滑层,最终导致摩擦系数呈现下降趋势。DLC薄膜对摩擦配副具有明显的减摩效果。     

DLC膜涂层硬质合金刀具的研究进展

类金刚石(DLC)膜涂层刀具的硬度高、摩擦系数低、耐摩擦和耐腐蚀性能强、抗粘结性能好,并且可以用来制作复杂、异型刀具,是未来刀具的一个重要发展方向。本文介绍了DLC膜的表面显微结构和Raman光谱并列举了DLC的制备方法 (包括磁控溅射、离子束沉积、脉冲激光沉积、真空阴极电弧沉积、等离子体增强型化学气相沉积)与分类。从酸蚀法、施加过渡层、表面微喷砂处理和掺杂4个方面分析如何提高膜基结合力,探讨了DLC膜的摩擦性能受湿度、温度和加工条件的影响。例举了几个国内外DLC涂层硬质合金刀具的使用范例,指出了目前研究工作的不足之处,提出了下一步研究工作的重点是优化DLC膜的制备工艺、提高膜基结合力和热稳定性以及加强DLC涂层硬质合金刀具的磨损机理研究。     

Adhesion improvement of hydrogenated diamond-like carbon thin films by pre-deposition plasma treatment of rubber substrate

For reduction of friction and enhancement of wear resistance of dynamic rubber seals, thin films of hydrogenated diamond-like carbon (DLC) have been deposited on hydrogenated nitrile butadiene rubber (HNBR) via magnetron-enhanced plasma chemical vapor deposition (ME-PCVD). Pre-deposition plasma treatment of HNBR substrate is proved to be crucial for the improvement of film performance due to enhanced interfacial adhesion. The columnar structure and the crack network formed during deposition enhance the flexibility of DLC thin films and exhibit strain tolerance up to 5%. Below 50% stretch strain and after unloading, thin DLC films of ∼ 300 nm thickness still adhere on the rubber substrates and no spallation or delamination is observed. The thin DLC film deposited on Ar-plasma pre-treated rubber at − 400 V substrate bias potential exhibits a very low coefficient of friction of 0.175 (compared to > 1 of uncoated HNBR rubber). After tribotests even under high normal load of 3 N, almost no wear can be seen on the films. Such tribological property is even better than that of 1 µm thick DLC or Me-DLC coated rubbers.     

Evaluation offing surfaces with several coatings for friction, wear and scuffing life

Friction and wear of the sliding components in an automobile cause an increase in both fuel consumption and emission. Many engine components involved with sliding contact are all susceptible to scuffing failure at some points during their operating period. Therefore, it is important to evaluate the effects of various surface coatings on the tribological characteristics of the piston ring and cylinder block surface of a diesel engine. Wear and scuffing tests were conducted using a friction and wear measurement of the piston ring and cylinder block in a low friction diesel engine. The frictional forces, wear amounts and cycles to scuffing in the boundary lubricated sliding condition were measured using the reciprocating wear tester. The tester used a piece of the cylinder block as the reciprocating specimen and a segment of the piston ring material as the fixed pin. Several coatings on the ring specimen were used, such as DLC, TiN, Cr-ceramic and TiAlN, in order to improve the tribological characteristics of the ring. The coefficients of friction were monitored during the tests, and the wear volumes of the piston ring surfaces with various coatings were compared. Test results show that the DLC coating exhibits better tribological properties than the other coatings. The graphite structure of this coating is responsible for the low friction and wear of the DLC film. The TiN and DLC coatings show better scuffing resistance than the other coatings. The TiN and Cr-ceramic coated rings show good wear resistance and high friction.     

Effect of metal ion implantation on thermal instability of diamond-like carbon films

In this work, molybdenum and tungsten ions were implanted onto the DLC films deposited by filtered cathodic vacuum arc. We investigated the effects of ion species and doses on carbon related bonding property such as the ratio of sp³ carbon to sp² phase, the chemical composition and tribological properties of the DLC films in the range of 200 to 600 °C. The oxidation starting temperature decreased with an increasing ion dose and ion mass owing to higher sp² carbon fraction. Oxidation of the implanted-metal element, however, keeps the DLC film from carbon sublimation by oxidation, offering stable tribological characteristics by covering it with a metal oxide layer at the high temperature.     

PVD涂层技术制备类金刚石薄膜及性能研究综述

介绍了采用物理气相沉积(PVD)技术制备类金刚石涂层的方法,进而论述了涂层的摩擦磨损和结合力等性能的研究现状和发展前景。分析并综述了类金刚石涂层的技术发展,以及制备类金刚石薄膜的方法和影响其性能的多种要素。表面涂有类金刚石薄膜的工件具有较高的硬度、良好的热传导率、极低的摩擦系数、优异的电绝缘性能等。类金刚石薄膜(DLC Films)是近年来兴起的一种以sp3和sp2键的形式结合生成的亚稳态材料,因其优异的减摩和抗磨性能,在摩擦学领域获得了广泛应用,是一种与金刚石涂层性能相似的新型薄膜材料。DLC涂层的性能研究大多集中在它的摩擦学特性和结合力性能,并且作为优质的涂层材料已被广泛应用于汽车、模具、刀具等领域。     

液压马达球铰副表面ZrO2涂层的摩擦学性能

为探索表面ZrO2涂层的球铰副在液压马达中的摩擦学规律,采用摩擦磨损试验机和白光干涉仪模拟ZrO2涂层的球铰副在不同载荷和转速的工况下,球铰副在液压马达中的摩擦磨损变化情况。分别从摩擦因数、磨损体积和磨痕形貌分析其摩擦磨损规律,从中找到最优的工况去提高ZrO2涂层的球铰副寿命和工作效率。通过开展控制变量试验发现：转速对ZrO2涂层的球铰副摩擦学性能的影响远大于载荷,在100 N-100 r/min时摩擦因数最小为0.059 6;磨损体积随载荷和转速的增大而逐渐增大,且在50 N-50 r/min时磨损体积最小为0.184 mm3。综合以上规律发现,载荷100 N和转速50 r/min工况下ZrO2涂层的球铰副减摩抗磨效果最好,低转速能够有效延长液压马达的使用寿命和提高机械效率。     

Tribological Properties of CrN/AlN Films Produced by Reactive Magnetron Sputtering

The microstructure of CrN/AlN films, prepared by reactive magnetron sputtering under various conditions, was analyzed and related to the wear behavior of the films. One set of films was prepared by conventional reactive magnetron sputtering, a second set adding an extra amount of reactive gas to the initial Ar + N₂ mixture and a third set adding an extra source of nitrogen near the substrate during sputtering. The samples were analyzed by scanning electron microscopy + energy dispersive microanalysis, high resolution scanning electron microscopy, atomic force microscopy, and x-ray diffraction. The results of the microstructural analysis revealed a clear difference in the morphology growth of the films when extra nitrogen was used compared to the conventionally prepared films. Formation of CrN was significantly faster than that of AlN. The most effective method to produce AlN was to introduce extra nitrogen. Pin-on-disk wear experiments were carried out in ambient air, to investigate the tribological behavior of the CrN/AlN system against a steel ball under dry conditions for various loads and a constant sliding speed. The results revealed that tribological properties of the layers improved unlike those of the untreated H13 steel. The friction behavior is closely related to the structure of the deposited films. The thicker CrN layer contributed to the higher load capacity of the coated steel when compared to the unmodified steel. However, wear life for the coating system was very short, denoted by the fairly poor adhesion of the film system to the steel substrate.     

Duplex diamond-like carbon film fabricated on 2Cr13 martensite stainless steel using inner surface ion implantation and deposition

A duplex plasma immersion ion implantation and deposition (PIIID) process, involving carbon ion implantation and diamond-like carbon (DLC) film deposition, is proposed to treat the inner surface of a tube. Samples of 2Cr13 martensite stainless steel were placed inside the tube to investigate the performance of the films. Carbon ion implantation was finished by biasing the tube with a high voltage, and the DLC film deposition was obtained by biasing the tube with a medium voltage. Raman spectrum, ball-on-disc, indentation and scratch tests were used to investigate the structure, tribological property and adhesion strength of the as-deposited films. The Raman spectrum shows that the sp³ bonding is formed in the as-synthesized film. Tribological and scratch test results reveal that the duplex DLC coating with the implantation time of 1 h has the largest adhesion strength and the best wear resistance.