类金刚石表面改性C/C复合材料的摩擦磨损性能

采用等离子体增强化学气相沉积法在C/C复合材料基底表面制备了不同厚度的类金刚石（DLC）表面改性膜;用球-盘对磨的方式测试了C/C复合材料基底和DLC膜在干态下的摩擦磨损性能。结果表明:制备的表面改性膜具有典型的DLC结构特征,均匀致密;随着沉积时间的延长,DLC膜厚度逐渐增大,膜基结合强度依次减小;C/C复合材料基底的平均摩擦因数为0.285 8,磨损率约为1.6×10^-4mm³·N^-1·m^-1,表面改性膜的摩擦因数较基底有较大程度的降低,在0.08～0.27之间,磨损率也降低了1～2个数量级,且沉积时间越长其摩擦因数越小、磨损率越低。     

脉冲偏压对PECVD制备DLC薄膜的结构及性能的影响

在不锈钢基材表面利用等离子体增强化学气相沉积技术(PECVD)改变脉冲偏压制备不同结构类金刚石薄膜(DLC)。分别采用表面轮廓仪、扫描电镜、拉曼光谱及电子探针分析薄膜的表面粗糙度、断面形貌、薄膜结构及成分,采用纳米压痕仪及划痕仪测试薄膜的纳米硬度、弹性模量和膜基结合力,采用球盘摩擦试验机测试薄膜在大气环境中的摩擦学性能。结果表明:脉冲偏压显著影响PECVD制备的DLC薄膜的表面粗糙度、微观形貌、膜基结合力、纳米硬度及摩擦学性能;随偏压的增大,DLC薄膜的表面粗糙度,摩擦因数及磨损量都先减小后增大,而膜基结合力则先增大后减小。其中2.0 k V偏压制备的DLC薄膜具有最强的膜基结合力,而1.6 k V偏压制备的DLC薄膜具有最低的表面粗糙度、最高的硬度和最优的减摩耐磨性能。     

氮化硅陶瓷表面DLC膜的制备及摩擦性能研究

利用等离子体基离子注入与沉积技术,在氮化硅陶瓷片表面制备200～400nm的类金刚石碳膜。测试薄膜的厚度、表面形貌、结构、膜基结合力,利用球盘试验机考察DLC膜的摩擦性能。结果表明:沉积薄膜均匀光滑;薄膜的硬度和弹性模量与基体差异较小,膜基结合力强;DLC膜具有较低的摩擦因数,抗磨性能优异。     

磁控溅射沉积TiB_2/DLC纳米多层膜的结构及其机械性能研究

采用非平衡磁控溅射系统在P(100)硅片和304不锈钢基底上制备TiB_2/DLC纳米多层膜。利用FESEM、TEM、XRD和AFM观察多层膜的微观结构和表面形貌;利用纳米压痕仪、维氏硬度计和CSM球-盘摩擦磨损试验机考察TiB_2靶电流对多层膜的机械性能和摩擦学性能的影响。结果表明:TiB_2/DLC多层膜具有良好的多层调制结构,多层膜沿TiB_2(101)晶向择优生长;多层膜的表面粗糙度随着TiB_2靶电流增加而增加;多层膜中的大量异质界面能显著提高薄膜的硬度及韧性,而且当TiB_2靶电流为2.0 A时,多层膜的硬度约为单层DLC薄膜的两倍;多层膜中具有硬质TiB_2层和软质DLC层的交替结构,在摩擦过程中,硬层TiB_2起到良好的承载作用,软层DLC起到良好的润滑作用,使多层膜具有比单层DLC薄膜更低的摩擦因数。     

高速钢表面镀覆DLC膜的结构及其摩擦特性研究

以高纯石墨作靶材、N2/Ar为工作气体,采用非平衡磁控溅射技术在高速钢上制备了光滑、致密、均匀的掺氮DLC膜。用XPS、Raman光谱仪表征了DLC膜的结构,并在球-盘摩擦试验机上研究了其摩擦特性。结果表明:工作气体中的N2比例对DLC膜结构及其摩擦特性影响较大,随着N2比例的增加薄膜中sp3的比例减少,而sp2和碳氮键的比例增加;随着N2比例的增加,薄膜摩擦因数先减后增,这与薄膜中sp3比例下降和sp2比例增加而导致薄膜的硬度以及内应力变化有关。就本试验而言,工作气体中N2比例不应高于20%。     

类金刚石薄膜水润滑摩擦学特性研究进展

综述类金刚石薄膜水润滑摩擦学特性的研究进展,评述薄膜在水环境中的摩擦磨损特性,分析薄膜种类、元素掺杂、对摩材料以及微结构对DLC薄膜水润滑摩擦学特性的影响,并阐述DLC薄膜在水中的摩擦磨损机制。指出:DLC薄膜水润滑摩擦学特性受薄膜制备参数和摩擦试验环境影响,通过与微结构的耦合可以进一步改善类金刚石薄膜的摩擦学特性。同时还展望了类金刚石薄膜水润滑摩擦学未来研究方向。     

类金刚石刀具涂层研究进展

类金刚石(DLC)涂层因其优良性能在有色金属和复合材料等材料的切削刀具表面广泛应用。基于DLC涂层刀具的使役性能,详述了DLC刀具涂层制备方法,主要包括离子束沉积法、磁控溅射法、电弧离子镀法和等离子体增强化学气相沉积法;阐述了不同类型DLC涂层材料的结构特征与性能特点,总结了DLC涂层刀具存在的膜—基结合力差、涂层厚度低和热稳定性差等问题及其优化方向;结合不同材料的加工特点,介绍了DLC涂层刀具在有色金属以及复合材料等材料加工中的应用情况;展望了DLC涂层未来的发展方向。     

具有表面类金刚石膜高速钢的耐磨性能

在高速钢基体上分别进行了制备类金刚石(DLC)膜和浸硫氮化两种表面处理,并以铸铁为对偶件,用MM200磨损试验机比较了经两种不同表面处理高速钢的耐磨性能,用扫描电子显微镜观察了磨痕形貌并分析了磨损机理。结果表明:在转速200 r·min~(-1)、载荷50 N的条件下,不论在油润滑状态还是在干摩擦状态,具有DLC膜高速钢的耐磨性能明显比浸硫氮化处理的好。     

调制比对多层DLC涂层摩擦及电化学行为的影响

研究调制比对多层类金刚石(Diamond-like carbon,DLC)涂层摩擦及腐蚀行为的影响。采用等离子体增强化学气相沉积技术成功制备了不同调制比的多层DLC涂层。利用扫描电子显微镜、原子力显微镜、划痕仪、摩擦磨损试验机及电化学工作站等表征手段评价了不同调制比多层DLC涂层的结构特点、力学性能、摩擦学性能以及耐腐蚀性能。结果表明:所制备涂层表面光滑、结构致密、膜基界面结合良好。其中1∶1为多层DLC涂层最佳调制比,该调制比涂层的硬度、弹性模量和抗裂纹萌生的临界载荷最大。同时,摩擦试验表明1∶1涂层具有最低的磨损率,且经720 h盐雾试验后仍然表现出较高的阻抗值。通过以上结果可以得出当调制比为1∶1时,多层DLC涂层具有良好的摩擦学性能及耐腐蚀性能。     

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.     

负偏压对DLC薄膜结构和摩擦学性能的影响

采用离子束溅射沉积镀膜法制备了DLC薄膜,研究了偏压对薄膜性能的影响。通过原子力显微镜(AFM)和拉曼光谱对DLC薄膜的表面形貌以及内部结构进行了分析表征。并用UTM-2摩擦磨损仪对其摩擦学性能进行了测试。结果表明,利用离子束溅射沉积制备的DLC薄膜具有良好的减摩抗磨性能。随着偏压的增加薄膜的摩擦因数先减小后增加,在-150 V偏压时,薄膜的摩擦学性能最好。     

Small amplitude reciprocating wear performance of diamond-like carbon films: dependence of film composition and counterface material

Small amplitude (50 μm) reciprocating wear of hydrogen-containing diamond-like carbon (DLC) films of different compositions has been examined against silicon nitride and polymethyl-methacrylate (PMMA) counter-surfaces, and compared with the performance of an uncoated steel substrate. Three films were studied: a DLC film of conventional composition, a fluorine-containing DLC film (F-DLC), and silicon-containing DLC film. The films were deposited on steel substrates from plasmas of organic precursor gases using the Plasma Immersion Ion Implantation and Deposition (PIIID) process, which allows for the non-line-of-sight deposition of films with tailored compositions. The amplitude of the resistive frictional force during the reciprocating wear experiments was monitored in situ, and the magnitude of film damage due to wear was evaluated using optical microscopy, optical profilometry, and atomic force microscopy. Wear debris was analyzed using scanning electron microscopy and energy dispersive spectroscopy. In terms of friction, the DLC and silicon-containing DLC films performed exceptionally well, showing friction coefficients less than 0.1 for both PMMA and silicon nitride counter-surfaces. DLC and silicon-containing DLC films also showed significant reductions in transfer of PMMA compared with the uncoated steel. The softer F-DLC film performed similarly well against PMMA, but against silicon nitride, friction displayed nearly periodic variations indicative of cyclic adhesion and release of worn film material during the wear process. The results demonstrate that the PIIID films achieve the well-known advantageous performance of other DLC films, and furthermore that the film performance can be significantly affected by the addition of dopants. In addition to the well-established reduction of friction and wear that DLC films generally provide, we show here that another property, low adhesiveness with PMMA, is another significant benefit in the use of DLC films.     

Friction and Vibration of Brake Friction Materials Reinforced with Chopped Glass Fibers

A diamond-like carbon (DLC) film exhibits excellent tribological properties. This type of film has an amorphous structure that is generally composed of hydrogen and carbon atoms, and it is the structure of sp²- and sp³-hybridized orbital carbon which brings about the extraordinary tribological properties of the DLC film. It is known that heating causes structural changes in a DLC film, and pre-heat treatment greatly affects the various properties of a DLC film. In this study, we focus on the effects of pre-heat treatment on the friction and wear properties of a hydrogenated DLC film and discuss the structural changes in the film. After pre-heat treatment, the tribological properties were evaluated using a ball-on-disk sliding tester. Our findings indicated that the friction and wear properties of the DLC film were improved by pre-heating up to 500 °C. An as-deposited DLC film had a friction coefficient of approximately 0.15, whereas it was approximately 0.03 for a film pre-heated at 500 °C. The structure of the DLC film was analyzed using micro-laser Raman spectroscopy. The analytic results of the Raman spectroscopy of the film surface showed that the G peak position had shifted toward a higher wave number. This result suggested that hydrogen had evolved from the DLC film because of pre-heat treatment. The half bandwidth of the G peak shifted toward a lower wave number with increases in the pre-heating temperature. This indicated that graphitization of the DLC film had been induced by pre-heat treatment. From these findings, we consider that the hydrogen evolution induced structural changes. Line analysis using micro-laser Raman spectroscopy was performed on a cross section of the pre-heated DLC film. The line analysis showed structural changes which were induced by hydrogen evolution, on the top of the DLC film. On the other hand, hydrogen evolution and graphitization were prevented inside the film, indicating that a gradient structure had been generated by pre-heat treatment. The low friction coefficient of the pre-heated DLC film was caused by graphitization of the DLC film surface. The graphite layer on the top of the film would induce lower shearing resistance at the sliding interface. This gradient structure of the DLC film plays an important role in improving the tribological properties of the pre-heated DLC film.     

Tribochemical effects on the friction and wear behaviors of diamond-like carbon film under high relative humidity condition

Friction and wear behaviors of diamond-like carbon (DLC) film in humid N₂ (RH-100%) sliding against different counterpart ball (Si₃N₄ ball, Al₂O₃ ball and steel ball) were investigated. It was found that the friction and wear behaviors of DLC film were dependent on the friction-induced tribochemical interactions in the presence of the DLC film, water molecules and counterpart balls. When sliding against Si₃N₄ ball, a tribochemical film that mainly consisted of silica gel was formed on the worn surface due to the oxidation and hydrolysis of the Si₃N₄ ball, and resulted in the lowest friction coefficient and wear rate of the DLC film. The degradation of the DLC film catalyzed by Al₂O₃ ball caused the highest wear rate of DLC film when sliding against Al₂O₃ ball, while the tribochemical reactions between DLC film and steel ball led to the highest friction coefficient when sliding against steel ball.     

Tribological behaviour of DLC coatings compared to different materials used in hip joint prostheses

The goal of the study carried out in the laboratory was to quantify the wear and the friction of two materials used for the manufacturing of hip prostheses. Tests used had to obtain in a short time the tribological behaviour laws of the materials. Tests on a hip simulator have been excluded because their cost and their duration were too high for a program of preliminary development of new materials.

To amplify wear phenomena, dry friction tests were carried out for two configurations: ball-on-disc and pin-on-disc. The influence of the contact pressure at constant sliding velocity on the wear of materials has been clearly shown.

Results obtained with several different tested materials (stainless steel/UHMWPE, stainless steel+DLC coating/UHMWPE, stainless steel+DLC coating/stainless steel+DLC coating, titanium alloy+DLC coating/UHMWPE, titanium alloy+DLC coating/titanium alloy+DLC coating, zirconium dioxide/UHMWPE, alumina/UHMWPE, alumina/alumina) have shown the superiority of DLC coatings. Promising results obtained during this study are in the validation stage on a hip simulator.     

高能球磨-粉末冶金法制备硫化亚铁/铁基轴承材料的摩擦学性能

以Fe、C和FeS为原料,采用高能球磨工艺和粉末冶金法制备了FeS/铁基轴承材料,研究了材料的微观结构,并考察了其摩擦磨损性能。结果表明：高能球磨工艺改善了FeS颗粒的分布均匀性及其与基体的界面结合,材料力学性能高于未球磨材料;FeS属固体润滑剂且具有良好的储油特性,油润滑条件下FeS向摩擦表面转移易形成液-固润滑膜,起到了良好的减摩抗黏着作用,FeS质量分数为8%的球磨铁基轴承材料具有较好的减摩耐磨特性和较高的承载能力。     

Tribological Properties of Diamond-Like Carbon Films in Low and High Moist Air

Diamond-like carbon (DLC) film was deposited on Si wafer by a plasma CVD deposition system using benzene. Tribological properties of the DLC film were evaluated using a ball-on-disk tribo-meter in low (RH 1720 %) and high humidity (RH 9095 %) conditions in air. The effect of sliding speed (4.2 mm/s to 25 mm/s) and load (1.06 N to 3.08 N) on friction and wear was investigated. The friction behavior of the DLC film was obviously different in low and high humidity. When tested under low humidity conditions, the friction coefficient decreased significantly with increasing speed, and increased with load. However, under high humidity conditions, the friction coefficient increased with the speed and decreased with increasing load. The wear of the DLC film was little influenced by the sliding speed, normal load and humidity; a level of 10^-8 mm³/Nm could be obtained in all tests. The formation of a uniform transfer layer would be the main factor which controlled the friction coefficient of the DLC films. Unlike the friction, the wear resistance of the DLC film is not so easy to discuss and may be affected mainly by the tribo-chemical reaction in all the test conditions.     

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。     

Friction mechanisms of Silicon wafer and Silicon wafer coated with diamond-like carbon film and two monolayers

The friction behaviour of Si-wafer, diamond-like carbon (DLC) and two self-assembled monolayers (SAMs) namely dimethyldichlorosilane (DMDC) and diphenyl-dichlorosilane (DPDC) coated on Si-wafer was studied under loading conditions in milli-newton (mN) range. Experiments were performed using a ball-on-flat type reciprocating micro-tribo tester. Glass balls with various radii 0.25 mm, 0.5 mm and 1 mm were used. The applied normal load was in the range of 1.5 mN to 4.8 mN. Results showed that the friction increased with the applied normal load in the case of all the test materials. It was also observed that friction was affected by the ball size. Friction increased with the increase in the ball size in the case of Si-wafer. The SAMs also showed a similar trend, but had lower values of friction than those of Si-wafer. Interestingly, for DLC it was observed that friction decreased with the increase in the ball size. This distinct difference in the behavior of friction in DLC was attributed to the difference in the operating mechanism. It was observed that Si-wafer and DLC exhibited wear, whereas wear was absent in the SAMs. Observations showed that solid-solid adhesion was dominant in Si-wafer, while plowing in DLC. The wear in these two materials significantly influenced their friction. In the case of SAMs their friction behaviour was largely influenced by the nature of their molecular chains.     

Fretting wear and fracture behaviors of Cr-doped and non-doped DLC films deposited on Ti–6al–4V alloy by unbalanced magnetron sputtering

Cr-doped and non-doped diamond-like carbon (DLC) films were deposited on a Ti–6Al–4V alloy substrate using an unbalanced magnetron sputtering (UBMS). Fretting wear behavior of the specimens was investigated using a ball-on-disk fretting tester. The fracture phenomenon of the DLC films was determined as the number of fretting cycles to reach a high value of the friction coefficient. The results showed that the Cr-doped and non-doped DLC films exhibited a lower friction coefficient and wear rate compared to that of the uncoated specimen. However, the Cr-doped DLC film fractured only in a few cycles, while the non-doped DLC film fractured after fretting cycles of about 200,000. A fracture mechanism of the Cr-doped and non-doped DLC films was reported in this study.