PECVD类金刚石涂层的结构及其摩擦腐蚀行为

采用等离子体增强化学气相沉积技术(PECVD)在316L不锈钢上制备类金刚石(DLC)涂层,系统地研究了所制备类金刚石涂层的表面形貌与结构、不同载荷下的摩擦磨损行为以及NaCl溶液(3.5 wt%)中不同腐蚀时间下的腐蚀行为。研究结果表明：制备的DLC涂层是由sp³键和sp²键杂化形成的非晶碳结构,其中sp²-C含量大于sp³-C,具有典型的类金刚石碳特征;DLC涂层结构致密,表面平滑,粗糙度仅为Ra=12.1 nm,能够与316L不锈钢基体结合紧密;DLC涂层的接触角为59.44°,说明涂层表现出一定的润湿性;摩擦磨损测试结果表明DLC涂层具有良好的润滑效果,摩擦系数能低至0.07～0.16,磨损率低至(3.85～6.71)×10^-7 mm³/(N·m);电化学测试得到DLC涂层自腐蚀电流密度为6.72×10^-6 A·cm^-2,阻抗模值高达7.05×10⁴Ω·cm^-2...     

不同载荷条件下浸银石墨材料水润滑摩擦磨损性能研究

采用环-块式摩擦磨损实验机,研究了水润滑条件下不同载荷和滑动时间对浸银石墨材料摩擦磨损性能的影响,利用表面轮廓仪和扫描电子显微镜对浸银石墨材料在磨合阶段和稳定磨损阶段的磨损行为进行分析和探讨。结果表明:滑动时间1 h内为磨合阶段,随载荷增加浸银石墨在水润滑条件下的摩擦系数降低,比磨损率增大。滑动时间5 h达到了稳定磨损阶段,高载荷导致浸银石墨在水润滑条件下的摩擦系数和比磨损率降低。在浸银石墨的稳定磨损阶段,500 N载荷下的摩擦系数最低,为0.038,700 N载荷下的比磨损率最低,为2.26×10^(-7)mm^(3)/Nm。高载荷条件下,浸银石墨在磨合阶段和稳定磨损阶段展现出相似的磨损机制,浸银石墨表面石墨区域发生较大磨损,增强的银颗粒支撑了水润滑界面间的载荷作用,边界润滑状态的局部流体润滑作用和小尺寸磨屑的自润滑作用,降低了浸银石墨材料的摩擦系数和比磨损率。     

Ni-C自润滑涂层重载下摩擦磨损行为

文章采用有限元模拟方法,并结合销盘式摩擦磨损实验,深入研究镍-石墨(Ni-C)固体自润滑涂层在干摩擦环境下与镍铬-碳化铬(NiCr-Cr3C2)硬质材料对磨下的摩擦磨损行为。模拟与实验结果表明,随外界载荷的升高,涂层塑性变形量及其表面温度不断增大;当外界载荷为52MPa时,Ni-C涂层表面形成连续稳定的石墨润滑层,使得摩擦系数最低降至0.2左右;当外界载荷增大至109MPa时,塑性变形量和摩擦系数显著增大,最终导致涂层断裂与脱落失效。     

芳纶浆粕增强丁腈橡胶复合材料的摩擦磨损性能

利用开炼机制备了丁腈橡胶(NBR)/芳纶浆粕(PPTA-pulp)复合材料。研究了在干摩擦和水润滑条件下,纤维含量、摩擦时间以及载荷对NBR/PPTA-pulp复合材料摩擦磨损性能的影响,并分析了磨损机理。结果表明,芳纶浆粕的加入能够很好地改善复合材料的力学性能和摩擦磨损性能,在相同条件下,当纤维质量分数为20%时,复合材料的综合性能最佳;在干摩擦条件下,随着摩擦时间延长,复合材料的摩擦系数下降,磨耗量增大;随着载荷增加,摩擦系数和磨耗量增大;水润滑条件下,复合材料的摩擦系数和磨耗量较干摩擦大幅度降低且比较稳定,时间和载荷对其影响很小;干摩擦时,复合材料的磨损机理主要为磨粒磨损和疲劳磨损;水润滑时,主要为轻微磨粒磨损。     

基于仿生结构的PE-UHMW水润滑尾轴承的摩擦性能

以鲨鱼皮为仿生对象,通过在超高分子量聚乙烯(PE-UHMW)水润滑尾轴承表面设计出菱形和棱条两种表面织构,研究在水润滑条件下PE-UHMW的摩擦性能。利用CBZ–1船舶轴承摩擦磨损试验机进行滑动摩擦磨损实验并对其摩擦系数进行监测采集,使用表面轮廓仪及超景深显微镜对其表面形貌进行观察,并测量了试样的平均磨损速率。结果表明:在载荷为0.8MPa下,当转速为50r/min时,棱条织构试样短时间内能够有效地降低摩擦系数;但随着转速上升至150r/min和500r/min时,棱条织构恶化了PE-UHMW试样的摩擦性能,而菱形织构试样的摩擦系数一直低于无织构试样;在转速为150r/min状态下,随着载荷从0.4MPa增加到0.8MPa,三种试样的平均摩擦系数及平均磨损速率逐渐上升,同时两种织构对PE-UHMW试样表面的摩擦性能起到不同程度的改善作用。     

无油润滑涡旋压缩机动静涡旋端面摩擦测试装置

为了研究无油润滑涡旋压缩机各摩擦副的摩擦特性,以动静涡旋盘端面摩擦为研究对象,根据无油润滑涡旋压缩机工作原理设计了试验测试平台,基于动力学理论,分析了动静涡旋盘端面摩擦损失;建立了动静盘端面摩擦力学分析模型。应用LabVIEW软件,编制了摩擦扭矩信号采集、存储和处理系统。试验装置可实现在不同转速、不同对偶材料摩擦副条件下,动静涡旋盘端面摩擦特性参数的测量,可为涡旋压缩机的理论研究和工程设计提供重要参考。     

轴瓦用C/C-SiC复合材料的摩擦磨损性能研究

本文通过液相气化热梯度法结合反应熔渗法制备出C/C-SiC复合材料,并通过环块摩擦磨损实验考察了在水润滑条件下不同载荷对其摩擦磨损特性的影响。实验在结果表明:C/C-SiC复合材料主要由碳纤维、碳纤维周围深色相PyC、灰暗相SiC相和灰白相Si组成。在水润滑条件下,C/C-SiC复合材料的摩擦系数较低,并随着载荷的增加而增大。当载荷从100N增加到400N时,摩擦系数从0.06增大到0.17左右。当载荷小于200N时,C/C-SiC复合材料的磨损率变化不明显;当载荷大于200N时,其磨损率随载荷的增加而显著增大。载荷较高时,C/C-SiC复合材料的磨损形式主要为磨粒磨损,材料表面磨损是磨粒的犁削作用和应力疲劳作用的共同结果。     

C／C-SiC复合材料的水润滑摩擦磨损特性研究

本文在MRH-3型环块式磨损试验机上,进行了C／C-SiC与Ni基合金摩擦副的摩擦磨损实验。测定了水润滑状态下,在相同转速,载荷,磨损时间条件下,配对摩擦副的摩擦系数和磨损率。用扫描电子显微镜（SEM）观察了配对摩擦副的磨损表面形貌。初步探讨了C／C-SiC复合材料的摩擦、磨损特性及机理,对C／C-SiC复合材料在水润滑条件下作为摩擦件使用提供了实验依据。     

微珠陶瓷材料的摩擦磨损性能

由高温摩擦磨损试验研究了复合莫来石(22.6%硅酸锆,75%莫来石,2.4%碳酸钙,质量分数)、硅酸锆和氧化铝3种陶瓷微珠材料在干摩擦和水润滑条件下的摩擦磨损性能,并对其磨损机理进行了分析.结果表明:3种材料的磨损均随着负荷的增加而加剧;在同等载荷下,水润滑条件相对于干摩擦,复合莫来石和硅酸锆的磨损都有所降低,氧化铝磨损反而加剧.在低载荷下,微珠磨损机理主要是塑性变形和微裂纹,在较高载荷下,主要磨损机理是脆性剥落和磨粒磨损.     

聚四氟乙烯及其石墨填充复合材料的摩擦磨损特性

对聚四氟乙烯（PTFE）及石墨填充PTFE复合材料在不同载荷、不同润滑条件下,以及在不同对磨时间内的摩擦磨损性能进行了研究。结果表明,石墨填充PTFE的耐磨性比纯PTFE提高很多,不同的润滑条件对PTFE和石墨填充PTFE的磨损量及摩擦系数的影响不一样,对纯PTFE,其磨损量在水润条件下较小,而对石墨填充PTFE,其磨损量在油润滑条件下较小。     

A study of hard diamond-like carbon films in mid-frequency dual-magnetron sputtering

A series of hydrogen-free diamond-like carbon (DLC) films were deposited by a mid-frequency dual-magnetron sputtering under basic conditions of Cr and C target power density between 6 and 18 W/cm², bias voltage in a range of − 100 V to − 200 V, and a pure argon atmosphere. Microstructure, microhardness, adhesion, friction and wear properties were investigated for the DLC films to be used as protective films on cutting tools and forming dies, etc. The DLC films exhibited some combined superior properties: high hardness of 30–46 GPa, good adhesion of critical load of 50–65 N, and friction coefficient about 0.1 in air condition. Properties of the magnetron-sputtered carbon films showed a strong dependence on flux and energy of ion bombardment during growth of the films.     

Synthesis of amorphous carbon films by plasma-based ion implantation with simultaneous application of DC and pulse bias

Carbon films were synthesized on a Si wafer by simultaneous application of pulse bias and DC bias by a plasma-based ion implantation system using an electron cyclotron resonance (ECR) plasma source with a mirror field. The relationship between the pulse biasing voltage and the properties of carbon films was investigated. The hardness and tribological properties of the carbon film improved as the pulse bias voltage was decreased from −10 kV to −2 kV. Diamond-like carbon (DLC) films with a low friction coefficient were formed by simultaneous application of a low pulse bias voltage, such as −2 kV, and a DC bias. During the friction test of the DLC film, excellent tribological properties were observed under a high conducted load, such as 20 N, which shows that not only the friction coefficient but also the durability during the friction test was improved. The improvement of the tribological property was attributed to the formation of a mixed layer at the interface between the DLC film and the Si substrate.     

Relationship between interlayer hardness and adhesion and pin-on-disc behaviour for fast atom beam source diamond-like-carbon films

The effect of interlayers of Ti, and Ti(C,N) on the adhesion, hardness and friction coefficient of DLC films deposited using a Fast Atom Beam (FAB) source has been studied. Values obtained for DLC films on top of interlayers were compared with those of DLC films directly deposited on Co-Cr substrates by both the FAB source and RF CVD techniques. The scratch test adhesion of such coatings can be classified in the following ascending order: DLC/Ti, DLC/no interlayer, DLC/Ti(C,N). The surface composite hardness is greatly improved by a Ti(C,N) interlayer. However, DLC films deposited on Ti(C,N) failed during the pin-of-disc test whilst those on Ti and without an interlayer exhibited low friction coefficients and excellent wear performance. An explanation is developed in order to explain the causes of film failure during the pin-on-disc test. For a given interlayer hardness, an adhesion threshold is required to survive the pin-on-disc test. The higher the hardness, the greater the required adhesion threshold, as interfacial shear stresses induced by the pin-on-disc are greater for hard surfaces, due to the smaller contact area.     

Tribological properties of DLC films with different hydrogen contents in water environment

Diamond-like carbon (DLC) films were deposited on silicon wafers by thermal electron excited chemical vapor deposition (CVD). To change the hydrogen content in film, we used three types of carbon source gas (C₇H₈, CH₄, and a CH₄+H₂) and two substrate bias voltages. The hydrogen content in DLC films was analyzed using elastic recoil detection analysis (ERDA). Tribological tests were conducted using a ball-on-plate reciprocating friction tester. The friction surface morphology of DLC films and mating balls was observed using optical microscopy and laser Raman spectroscopy.Hydrogen content in DLC films ranged from 25 to 45 at.%. In a water environment, the friction coefficient and specific wear rate of DLC films were 0.07 and in the range of 10⁻⁸–10⁻⁹ mm³/Nm, respectively. The friction coefficient and specific wear rate of DLC film in water were hardly affected by hydrogen content. The specific wear rate of DLC film with higher hardness was lower than that of film with low hardness. Mating ball wear was negligible and the friction surface features on the mating ball differed clearly between water and air environments, i.e., the friction surface on mating balls in water was covered with more transferred material than that in air.     

The effect of annealing on mechanical and tribological properties of diamond-like carbon multilayer films

The diamond-like carbon (DLC) multilayer films have been deposited by plasma CVD deposition onSi wafer substrate. The deposited films have then been post-annealed in vacuum at 250 °C for 2 h. Changes in internal stress, hardness, critical load, friction coefficient and wear have been investigated toassess the influence of annealing on mechanical and tribological properties of DLC multilayer films. At the same time, DLC single layerfilms are also deposited and annealed in the same method for a comparison.The results show that there is 28–33% decrease in internal stress and 10–13% decrease in hardness of theDLC single layer films after the anneal treatment. However, for the DLC multilayer films, there is 41–43% decreasein internal stress and less than 2% decrease in hardness. In addition, the annealed DLC multilayer filmhas the same friction and wear properties as that un-annealed film. This result indicates that the anneal treatment isan effective method for the DLC multilayer films to reduce the internal stress and to increase the critical load.The by-effect of the annealing, decrease of hardness and wear resistance of the multilayer film, can be restrictedby the multilayer structure.     

Mechanical and tribological properties of diamond-like carbon films prepared on steel by ECR-CVD process

Diamond-like carbon (DLC) films were prepared on AISI 440C steel substrates at room temperature by the electron cyclotron resonance chemical vapor deposition (ECR-CVD) process in C₂H₂/Ar plasma under different conditions. In order to prevent the inter-diffusion of carbon and improve the adhesion strength of DLC films, functionally gradient Ti/TiN/TiCN/TiC supporting underlayers were deposited on the steel substrates in advance. Using the designed interfacial transition layers, relatively thick DLC films (1–2 μm) were successfully prepared on the steel substrates without delamination. By optimizing the deposition parameters, DLC films with hardness up to 28 GPa and friction coefficients lower than 0.15 against the 100Cr6 steel ball were obtained. In addition, the specific wear rates of the films were found to be extremely low (∼10⁻¹⁷ m³/Nm). The friction-induced graphitization mechanism of DLC was confirmed by micro-Raman analysis.     

清洗预处理对手表外观件表面镀类金刚石薄膜性能的影响

为解决手表外观件镀层的附着力和硬度不高而产生的膜层脱落和磨损露底等问题,采用阳极层流型气体离子源结合非平衡磁控溅射技术制备了类金刚石膜层,研究了镀前清洗工艺对膜层附着力和耐磨性能的影响.结果表明,所制备的类金刚石膜均匀亮黑,显微硬度为2 232 HV,摩擦系数为0.15.在同一镀膜工艺条件下,手表外观件经彻底清洗后,其...     

The effect of CNT content on the surface and mechanical properties of CNTs doped diamond like carbon films

The carbon nanotubes (CNTs) doped diamond like carbon films were carried out by spinning coating multi-walled carbon nanotubes (CNTs) on silicon covered with diamond like carbon films via PECVD with C₂H₂ and H₂. The results show that the I_D/I_G and sp²/sp³ ratios are proportional to the CNT contents. For wettability and hydrogen content, the increase of CNT content results in more hydrophobic and less hydrogen for CNT doped DLC films. As for mechanical properties, the hardness and elastic modulus increases linearly with increasing CNT content. The residual stress is reduced for increasing CNT content. As for the surface property, the friction coefficient is reduced for higher CNT content. For CNT doped DLC films, the inclusion of horizontal CNT into DLC films increases the hardness, elastic modulus and reduces the hydrogen content, friction coefficient and residual stress. Like the light element and metal doping, the CNT doping has effects on the surface and mechanical properties on DLC which might be useful to specific application.     

Synthesis and mechanical properties of carbon nanotube/diamond-like carbon composite films

Diamond-like carbon (DLC) coatings were successfully deposited on carbon nanotube (CNT) films with CNT densities of 1 × 10⁹/cm², 3 × 10⁹/cm², and 7 × 10⁹/cm² by a radio frequency plasma-enhanced chemical vapor deposition (CVD). The new composite films consisting of CNT/DLC were synthesized to improve the mechanical properties of DLC coatings especially for toughness. To compare those of the CNT/DLC composite films, the deposition of a DLC coating on a silicon oxide substrate was also carried out. A dynamic ultra micro hardness tester and a ball-on-disk type friction tester were used to investigate the mechanical properties of the CNT/DLC composite films. A scanning electron microscopic (SEM) image of the indentation region of the CNT/DLC composite film showed a triangle shape of the indenter, however, chippings of the DLC coating were observed in the indentation region. This result suggests the improvement of the toughness of the CNT/DLC composite films. The elastic modulus and dynamic hardness of the CNT/DLC composite films decreased linearly with the increase of their CNT density. Friction coefficients of all the CNT/DLC composite films were close to that of the DLC coating.     

Superlow friction and diffusion behaviors of a steel-related system in the presence of nano lubricant additive in PFPE oil

The lubrication performances of diamond like carbon (DLC) films were investigated by a ball-on-disc tribometer under perfluoropolyether (PFPE) oil lubrications. The influence of nano lubricant additives in PFPE oil on the tribological properties of DLC films was evaluated. The experimental results show that the solid-liquid synergy lubrication is beneficial to improve the tribological properties of the steel-related friction system and the tribological properties of the friction pair are significantly influenced by lubrication modes and the types and contents of nano lubricant additives under PFPE oil lubrication. The friction system exhibits super low friction behaviors under PFPE oil with nano MoS₂ lubricant additive lubrication due to the excellent compatibility of nano MoS₂ additives with PFPE oil. Coefficient of friction (CoF) of the friction system is as super low as 0.02 under PFPE oil with 0.2?wt.% nano MoS₂ additive lubrication. Superlow friction mechanism is attributed to the pointlike contact of nano MoS₂ additive as soft phase and the excellent diffusion behaviors of nano MoS₂ additives in PFPE oil. The potential usefulness of nano MoS₂ particles as the lubricant additives in PFPE oil for the steel/DLC films has been demonstrated.