High-Temperature Friction and Wear of Ag/h-BN-Containing Ni-based Composites Against Steel

In order to attain self-lubrication in a wide range of temperatures, Ni-based powder metallurgy (P/M) composites containing different amounts (8–20 wt%) of Ag were prepared, and their friction and wear characteristics were investigated against AISI 52100 steel at temperatures of 25, 400, and 600 °C. One composite containing 12 wt% Ag and 4 wt% h-BN was also prepared and tested under the same conditions to analyze the effect of addition of h-BN on the friction and wear behaviors. The composites mainly consisted of Ni-based solid solution, free tungsten, Ag, and BN as revealed by XRD and EDS analyses. The friction coefficients and wear rates were found to decrease with increasing temperature and amount of silver. The friction coefficients shown by the composites containing relatively higher amounts of silver were in the range from 0.25 to 0.16 with temperature increasing from RT to 600 °C. The wear rates of the Ag/h-BN-containing composites were approximately an order of magnitude lower than those of the Base Alloy (having no solid lubricant) at all the temperatures. The addition of 4 wt% h-BN resulted in slightly greater friction and wear in comparison to the composites containing only silver.     

石墨含量对石墨/铜复合材料载流摩擦磨损性能的影响

以石墨/铜复合材料和QCr0.5铜合金为摩擦副,在自制的销盘摩擦磨损试验机上进行不同电流密度下的摩擦磨损试验,考察石墨含量对石墨/铜复合材料载流摩擦磨损性能的影响。结果表明:随着石墨含量的增加,石墨/铜复合材料的摩擦因数下降,载流效率和磨损率先下降后升高,石墨质量分数为10%时,载流效率最高,为12.5%时磨损率最低;随着电流密度的增加,石墨/铜复合材料的摩擦因数和载流效率下降,磨损率逐渐增加;石墨/铜复合材料在载流摩擦过程中存在黏着磨损、磨粒磨损和电弧烧蚀,电流密度较大时,电弧烧蚀比较严重。     

浸锑石墨摩擦磨损特性研究

为使石墨产品能够应用于高温及重载条件下且能表现出良好的的耐磨性和自润滑性,使用机械加压工艺将熔融锑浸入石墨坯料气孔中制得浸锑石墨复合材料,并对浸渍前后样品的微观结构、摩擦磨损性能进行了研究,评价了浸锑石墨浸渍后磨损量及润滑性能的变化。结果表明,浸锑后磨损量减少96.6%,摩擦因数降低了45%,证明浸锑后石墨材料的摩擦磨损性能有所提高。     

Friction and Wear Behaviors of Indirect Dental Restorative Composites

Under different simulated oral environments (distilled water, artificial saliva, and a cola soft drink) and with a small-amplitude reciprocating apparatus, the friction and wear behaviors of 5 types of indirect dental restorative composites relative to uniform Si₃N₄ balls were investigated. Test parameters were: normal load with 20 N, reciprocating amplitude (1,000 μm), and frequency (0.25 Hz). Tests lasting up to 5,000 cycles were conducted. The wear damage characteristics are discussed in detail based on an analysis of friction behaviors, SEM observations, and 2- and 3-D profile microscopy. The results indicated that the hybrid resin composites with high filler weight and well filler distributions, such as Filtek P60, possess better wear resistance than nano-filled composites, such as VITA ZETA and VITA LC, with relatively low filler weight. Artificial saliva and a cola soft drink could play important roles in lowering the friction coefficient and wear loss of dental composites. The cola soft drink displayed a better lubrication effect. The degree of sensitivity to changes in lubrication conditions varies with different dental composites. Abrasive wear is the main wear mechanism for the 5 composites, but brittle cracks and delamination are more common for VITA ZETA and VITA LC.     

聚合物填充聚四氟乙烯复合材料的摩擦磨损性能

采用机械共混-冷压成型-烧结的工艺制备了PEEK、PPS填充PTFE基粘弹．摩擦型阻尼材料,用环-块式磨损试验机研究了在干摩擦条件下的摩擦磨损性能;用扫描电子显微镜观察磨损表面形貌和内部组织结构。结果表明：混合填充PEEK和PPS时,2种填充物的比例对材料的摩擦因数影响不大,当二者含量相近时,摩擦因数最大;填充物对磨损性能的影响与对摩擦因数的相同;随着PEEK含量的增加和PPS含量的减少,材料的磨损方式由疲劳剥落磨损为主转变为犁削、粘着磨损;PTFE含量的增加,使得复合材料的摩擦因数减小,而磨损有所增大。综合考虑认为,PTFE与适当比例的PEEK／PPS混合填充,具有合适的摩擦因数和较好的耐磨性,能够满足特殊工况下阻尼材料的需要。     

Friction and Wear Behaviors of Ag/MoS2/G Composite in Different Atmospheres and at Different Temperatures

Silver-based composite with 15?vol% MoS₂ and with 5?vol% graphite was prepared by powder metallurgy method. The impacts of the counterface materials, atmosphere, and temperature on the tribological behavior of the composite were investigated. It was found that when sliding against brass less effective lubricating film formed, causing a higher friction and wear comparing with ASTM-1045 steel. With the increasing proportion of oxygen in the O₂/N₂ atmosphere, the wear rate and friction coefficient ascended slightly. At 200?°C, the combination lubrication of graphite, MoS₂, and Ag contributed to a low friction coefficient (0.07) and wear rate (6.56?×?10^?6?mm³/Nm). At 400?°C, graphite lost its lubricating role, while silver became excessively soft. Large amount of MoS₂ was oxidized into MoO_3, and the residual MoS₂ formed some island-like lubricating films. Severe adhesive wear occurred on the contact surface, which led to a high friction coefficient (0.25) and a great increase of the wear rate (23.2?×?10^?6?mm³/Nm). At 600?°C, a relatively low friction coefficient (0.1) was obtained because of the formation of high-temperature solid lubricants, (Ag₂Mo₄O₁₃ and Ag₂Mo₂O₇) and liquid Ag₂Mo₂O₇. However, the wear rate at 600?°C was the highest (32.6?×?10^?6?mm³/Nm) due to the thick transfer layer.     

铜-10%石墨合金的载流摩擦磨损性能

为提高铜基合金的载流摩擦磨损性能,采用粉末冶金方法制备了含10%石墨的铜基合金,并在自制的销盘式载流摩擦磨损试验机上进行了不同电流和滑动速度下的摩擦磨损试验.结果表明:与不含石墨的铜合金相比较,在不同电流和滑动速度下,加入10%石墨铜合金的摩擦因数和磨损率均降低,耐磨性能明显提高,摩擦因数稳定.     

SiO2填充聚四氟乙烯复合材料的摩擦学行为研究

用机械共混和冷压成型、热烧结的方法制备了琐体积含量不同粒径的SiO2填充PTFE样品，用M-2000摩擦磨损试验机评价了不同样品在干摩擦下的摩擦学性能；用X射线能量损失谱（EDS）观察分析了摩前后Si元素在样品表面的分布情况，结果表明：在本实验所采用的实验条件下，SiO2/PTFE复合材料的摩擦系数随SiO2体积含量的增加而增大，抗磨损能力则有一个最佳含量；填料粒径不同其体积填充分数对复合材料摩擦磨损性能的作用规律不同，在相同的体积分数下，粗SiO2填充PTFE的摩擦系数小于细SiO2填充PTFE的摩擦系数，且其随SiO2填充分数增加而增大的趋势远小于细SiO2填充PTFE；其具有最好抗磨能力的最佳体积填充含量也大于细SiO2的体积填充含量，SiO2这种填充作用规律可由其在PTFE基体中的形态结构特征来解释。     

Friction and Wear of Epoxy Composites Containing Surface Modified SiC Nanoparticles

The authors of the present paper evaluated the sliding wear behaviors of epoxy and its composites filled with untreated and treated SiC nanoparticles. The experimental results indicate that the nanoparticles pretreated by graft polymerization of polyacrylamide effectively improved the overall performance of the matrix epoxy. In comparison with the untreated SiC nanoparticles, the grafted SiC nanoparticles led to more significant reduction in frictional coefficient and wear rate of epoxy. Even under high contact pressure, the composites with grafted SiC nanoparticles possessed the highest wear resistance. The strong interfacial bonding between the grafted SiC nanoparticles and the matrix should account for the properties enhancement. Accordingly, a feasible way of efficiently applying SiC nanoparticles to the preparation of wear resisting nanocomposites has been developed.     

电弧能量对C/C复合材料的载流摩擦磨损行为的影响

在自制的销盘载流摩擦磨损试验机上,研究电弧能量对C/C复合材料/铬青铜摩擦副载流摩擦磨损行为的影响,并利用扫描电镜和能谱仪等对磨损表面进行了表征.结果显示,随着电弧能量的增加,C/C复合材料的磨损也随之增加;在较低的电弧能量下,电弧对材料的侵蚀不严重,材料的磨损也不严重,其磨损机制主要表现为磨粒磨损和少量的电气磨损,随着电弧能量的增加,磨损率急剧增加,此时磨损机制主要表现为电气磨损; 在电弧作用下,C/C复合材料的电弧侵蚀机制为蒸发侵蚀和材料转移.     

干摩擦条件下Al_2O_3基复合材料的摩擦磨损特性

以用SiC、Ti(CN)和ZrO2颗粒增韧的三种Al2O3基复合材料为研究对象,利用销盘式摩擦磨损试验机研究了它们的摩擦磨损性能,通过扫描电子显微镜对其磨损形貌进行了观察和分析.结果表明:在本试验条件下,Al2O3基复合材料的耐磨性能与添加剂的种类有关,其耐磨性能好坏顺序为Al2O3/Ti(CN)、Al2O3/SiC、Al2O3/ZrO2;Al2Os/SiC复合材料的磨损机理主要为疲劳磨损和脆性断裂,Al2O3/ZrO2和A12O3/Ti(CN)复合材料的磨损机理主要为磨粒磨损.     

纳米高岭土和石墨填充PTFE复合材料摩擦磨损性能

采用模压法制备石墨和纳米高岭土填充的聚四氟乙烯(PTFE)复合材料,在往复式滑动摩擦磨损试验机上测试了其的干滑动摩擦磨损性能,试验机往复频率为1.0 Hz.用扫描电镜观测和分析试样的磨损表面.结果表明:石墨和纳米高岭土共同填充的PTFE,在改善其耐磨性的同时,又保持了低的摩擦因数,其中含10%高岭土和5%石墨的PTFE复合材料表现最佳,稳定阶段的摩擦因数保持在0.11左右,耐磨性比纯PTFE提高了大约90倍.     

铜包石墨含量对铜锰铝复合材料摩擦磨损性能的影响

为改善铜锰铝合金的烧结性能,并提高其在干摩擦下的摩擦磨损性能,以铜包石墨作为自润滑相加入到铜锰铝合金中,采用等离子真空压力烧结方法制备铜锰铝/石墨复合材料,分析铜包石墨含量对复合材料的密度、硬度的影响,探讨不同复合材料在干摩擦和油润滑条件下的摩擦磨损性能.结果表明:相比真空和氢气还原气氛下的烧结方式,等离子体烧结铜锰铝...     

Friction and Wear Behavior of Copper Matrix Composites Reinforced with SiC and Graphite Particles

The objective of this paper is to investigate the friction behavior and wear mechanism of copper matrix composites reinforced with SiC and graphite particles. The results indicate that a graphite-rich mechanically mixed layer (MML) formed on the tribo-surface was responsible for the good tribological properties of the hybrid composites at low normal loads. When graphite content was high enough for delamination wear to take place at high load, wear resistance deteriorated. A continuous supply of graphite to the tribo-surface is an important precondition for the formation of a graphite-rich MML and the benefit of its anti-friction properties for the copper hybrid composites.     

生物摩擦磨损润滑剂的润滑特性

关节转换已广泛应用于关节炎晚期治疗,外伤致残和滑瘤切除手术中。关节转换材料的耐磨性能会直接影响转换关节的使用寿命和使用质量。蒸馏水、盐水、血浆、血清等均被用作生物摩擦磨损研究的润滑剂,但是对这些润滑剂的润滑特性并未认真考察。本文应用ＴＬＴ－１型弹流试验台对血浆在内的几种生物摩擦磨损润滑剂的润滑特性进行了研究,结果表明血浆的润滑性能最好。     

Friction and Wear Protection Performance of Synthetic Siloxane Lubricants

Several new siloxane lubricants were synthesized with linear and ring-shaped branch structures of various lengths and branch contents, aiming at a search for better molecular design for lower boundary friction and more effective surface protection against wear of materials. Their molecular structure and mass were measured by means of nuclear magnetic resonance and gel permeation chromatography, respectively. The new lubricants were compared with commercially available polysiloxanes, poly-α-olefins, and perfluoropolyether in lubricating a steel ball-on-steel disk interface using a tribotester at a load of 1.76 GPa and an entrainment speed of 0.025 m/s. The results are used to explain the effects of alkyl branch length L, pendant type J, percent of branch functional monomers Q, and degree of polymerization DP on siloxane design for the most effective boundary lubrication.     

Wear and Friction Studies of Neopentyl Polyol Ester Lubricants

Wear and friction properties of three representative neopentyl polyol esters, together with the common diester lubricant base, bis(2-ethylhexyl) sebacate, were studied with the four-ball wear machine at 266 F and 5–50 kg load in the presence and in the absence if tricresyl phosphate. The rubbing surfaces were 52100 steel, 440 C stainless steel and M-50 steel. With 52100 low-chromium steel balls, wear rates were largely independent of ester type. Percolated tricresyl phosphate reduced wear moderately at low loads only. Stainless steel 440 C and M-50 steel gave results significantly different from those with 52100 steel at all loads. In the case of the stainless steel wear was greatly increased at a load of 50 kg and tricresyl phosphate (1%) was ineffective at all loads. M-50 steel gave the lowest wear rates. It showed no response to tricresyl phosphate. Average friction coefficients of all the steels showed little change with the variables examined except for a small increase with load and for slightly lower values with M-50 steel.     

SiC和石墨颗粒混杂增强铜基复合材料的摩擦磨损性能

采用粉末冶金方法制备了SiC和石墨混杂增强铜基复合材料,研究了该复合材料在不同载荷条件下的摩擦磨损性能,并通过观察磨损表面形貌,研究其磨损机理。结果表明:在摩擦过程中,SiC颗粒作为载荷的主要承载单元,起到了较好的硬质承载支点的作用,石墨颗粒则发挥了较好的自润滑减摩效果,二者协同作用明显提高了铜基复合材料的耐磨性;该复合材料的磨损机理主要以磨粒磨损为主。     

聚苯酯填充聚四氟乙烯复合材料摩擦学行为研究

采用聚苯酯（Ekonol）、Ekonol／PAB纤维增强聚四氟乙烯（PTFE）制备利用转移膜润滑的摩擦副材料，并研究了两组材料在于摩擦条件下与9Cr18轴承钢对摩时的摩擦学性能；运用扫描电镜分析了两组材料磨损表面形貌和磨损机理。结果表明：随着Ekonol含量的增大，Ekonol填充PTFE复合材料的摩擦因数逐渐增大，当Ekonol质量分数超过25％时摩擦因数略有下降，磨损方式由以犁削磨损为主转变为以疲劳磨损为主；而Ekonol／PAB纤维填充门FE复合材料的摩擦因数，随Ekonol含量的增大而增大，磨损方式由以粘着磨损为主转变为以疲劳磨损为主。Ekonol／PAB纤维填充PTFE复合材料的摩擦学性能优于Ekonol填充PTFE复合材料。     

载流下MoS2/Ag纳米复合薄膜摩擦学性能

MoS₂基纳米复合薄膜具有良好的摩擦学性能,但较差的导电性能限制了其在载流条件下作为润滑材料的应用。为提高MoS₂基纳米复合薄膜的导电性能,采用非平衡磁控溅射系统沉积2种不同Ag含量的MoS₂/Ag纳米复合薄膜,并在不同的电流条件下研究MoS₂/Ag纳米复合薄膜与GCr15钢球对摩时的摩擦学性能。结果表明：在载流下2种MoS₂/Ag纳米复合薄膜表现出相似的摩擦性能,而低掺杂MoS₂/Ag薄膜具有更佳的耐磨性能,这归因于低掺杂MoS₂/Ag薄膜具有较好的力学性能;无载流时,MoS₂/Ag纳米复合薄膜在摩擦过程中生成的氧化物颗粒增加了磨损、降低了润滑性,磨损机制主要为磨粒磨损;电流小于0.5 A时,电流促进了转移膜形成,使得摩擦因数降低,但磨损率增加,磨损机制主要为黏着磨损;当电流大于0.5 A时,由于电弧烧蚀加速了薄膜的磨损,磨损机制主要为磨粒磨损、黏着磨损和电弧腐蚀磨损。