聚合物及其复合材料摩擦学研究新进展

综述了聚合物及其复全材料的摩擦学新进展,并指出了聚合物及复合材料的摩擦学研究方向。     

自润滑活塞环的摩擦磨损分析

主要介绍了目前无油润滑压缩机行业普遍使用的自润滑材料聚四氟乙烯的结构特性，自润滑活塞环的摩擦磨损以及外部因素对自润滑活塞环摩擦磨损的影响。     

聚四氟乙烯填充高岭土基矿物聚合物复合材料的摩擦学性能

研究了PTFE填充量对高岭土基矿物聚合物复合材料的力学性能和摩擦磨损性能的影响,利用XRD、SEM分析了材料的微观结构和磨损表面形貌。结果表明:填充PTFE对矿物聚合物材料的力学性能会有一定程度的降低,但可以有效改善复合材料的摩擦磨损性能,当PTFE体积分数为30%时,摩擦因数和磨损率均达到最低,分别为0.429和1.22×10-5mm3/N·m;当PTFE含量较高时,磨损机理除了磨粒磨损外还有对偶件的粘着转移。     

影响无油润滑压缩机活塞环寿命的因素及对策

从使用和装配方面，分析了影响无油润滑压缩机活塞环寿命的因素，并对常见问题提出了对策。     

填料种类对聚苯酯基复合材料摩擦学性能的影响

在聚苯酯(Ekonol)中分别添加不同种类的填料,制备出一系列性能不同的Ekonol基复合材料,研究了填料的形态、性质对Ekonol复合材料摩擦磨损性能的影响,分析了磨损面、对磨面转移膜形貌,并探讨了摩擦磨损机制。结果表明,在填料的填充量相同时,层状固体润滑剂聚四氟乙烯(PTFE),由于从本质上改善了非熔融Ekonol的内部粘结,且协助形成较为连续、平滑的转移膜,对Ekonol摩擦学性能的改善最为明显;其次为纤维状填料。相比于尺寸细微的六钛酸钾晶须,粗大的玻璃纤维(GF)或碳纤维(CF)之间相互交错,对Ekonol起到了较好的承载骨架作用,更为有效提高Ekonol的摩擦学性能。GF比CF与Ekonol之间的亲和性较好,对应于GF/Ekonol复合材料的摩擦学性能优于CF/Ekonol复合材料;纳米颗粒填料对Ekonol有着弥散增强作用,但对Ekonol摩擦学性能的改善效果最差。     

润滑油添加剂对聚合物材料摩擦磨损性能的影响研究

利用MM－200型磨损试验机考察了ZDDP对聚合物材料（PTFE、PI及MCPA）－GCr15轴承钢摩擦副摩擦磨损性能的影响。研究发现，液体石蜡及含ZDDP的液体石蜡润滑均可大幅度改善聚合物材料的摩擦磨损性能，且使其摩擦系数比干摩擦时降低一个数量级，摩擦副表面的ZDDP吸附膜均在不同程度上提高聚合物材料的耐磨性，但其对聚合物材料的摩擦性能影响不大。     

润滑油添加剂对聚合物及其复合材料摩擦磨损性能的影响

利用MHK-500型环-块磨损试验机研究了二烷基二硫代磷酸锌(ZDDP)对几种聚合物及其复合材料-金属摩擦副油润滑摩擦磨损性能的影响。结果表明,液体石蜡中的ZDDP对尼龙66(PA66)及聚酰亚胺(PI)-GCr15轴承钢摩擦副的摩擦系数影响不大,但却使聚四氟乙烯(PTEE)及其复合材料-GCr15轴承钢摩擦副的摩擦系数略有降低。PTEE及其复合材料-GCr15轴承钢摩擦副表面的ZDDP吸附膜具有一定的抗磨作用,它大幅度降低了Pb、PbO及MoS     

铝-塑自润滑材料的结构分析设计与摩擦磨损性能

对高强铝合金(7075)———超高分子量聚乙烯(UHMWPE)自润滑材料进行结构分析设计,通过压缩试验与往复式滑动摩擦磨损试验测试了新材料的承载力、摩擦热、摩擦因数与磨损率;用扫描电镜观察了磨损表面的磨痕形貌并分析了磨损机理。结果表明:这种新型自润滑材料的比强度较高,抗压强度达到100MPa,摩擦因数小于0.16;在正压力P=8.5kN、往复频率300次/min(30mm/s)、滑动行程S=324m的室温干摩擦条件下,磨损率为1.7×10-6mm3/(N.m),摩擦温度为65℃;这种新型自润滑材料在磨合期主要表现为犁沟和粘着磨损,磨损后期表现为表层和亚表层的脆性断裂。     

锡青铜-钢背双金属固体自润滑复合材料的摩擦性能研究

采用粉末冶金工艺制备含石墨固体润滑剂的锡青铜-钢背复合材料,研究了石墨含量对材料的硬度、显微组织和摩擦磨损性能的影响,并考察了摩擦磨损机制。结果表明:在含石墨的青铜-钢背双金属材料中,随着石墨含量的增加,材料的硬度逐渐降低,摩擦磨损性能逐渐改善,但是其显微组织的均匀性也逐渐变差;在石墨含量为3%～5%(质量分数)时,双金属材料既具有较好的摩擦磨损性能,同时表面铜合金层与钢背的黏结强度也很高;随着速度和负荷的增加,材料的摩擦因数降低,磨损增加;摩擦过程中,石墨在摩擦面上成膜是材料具有减摩自润滑性能的主要原因。     

水润滑下偶件表面粗糙度对PTFE复合材料摩擦学性能的影响

通过水润滑下的摩擦磨损实验,研究了偶件表面粗糙度对MoS2/PTFE复合材料摩擦学性能的影响,分析了在不同的偶件表面粗糙度下的摩擦学行为.实验结果表明:在水润滑下,一般存在着一个较佳的偶件表面粗糙度范围,在这个范围内可以取得较低的摩擦因数和磨损率;当偶件表面粗糙度高于这个范围时,摩擦磨损机制主要是机械作用;而当偶件表面粗糙度低于这个范围时,则主要是由于分子作用导致摩擦磨损.即当偶件表面粗糙度超出某一范围时,摩擦磨损行为将发生转变.     

Enhanced Mechanical and Tribological Properties of Graphene-Reinforced TiAl Matrix Composites

This study investigated the mechanical properties and dry-sliding friction and wear behaviors of graphene-reinforced TiAl matrix composites in expectation of providing valuable information for the application of graphene. The results suggested that the incorporation of graphene apparently improved the microhardness, fracture toughness, and tribological properties of the composites. For the composite with 3?wt% graphene, the microhardness increased by 129%, the fracture toughness increased by 149%, the friction coefficient decreased by 37% and the wear rate decreased by 78%. Also, the microstructural analyses of the worn surfaces indicated that three types of graphene-rich films, with different percentages of coverage, were generated on the worn surfaces under various wear conditions. An evolution mechanism of the films as a function of wear conditions was proposed, and the corresponding variation of friction and wear behavior was also discussed.     

CrN 活塞环涂层的磨擦学性能

以PVD方法在不锈钢渗氮活塞环基体上沉积了厚约30 μm的CrN涂层.采用2种GF-3等级的全配方发动机油作为润滑剂,在SRV试验机上,对比了具有/没有CrN涂层的不锈钢渗氮活塞环的摩擦学性能.试验结果表明,CrN涂层能使摩擦因数数较快的稳定且数值较低,同时活塞环及其对磨缸套的磨损量也大大降低,对磨缸套的磨损量减少了80%以上.SEM分析结果表明,由于CrN涂层具有较高的硬度和较低的表面粗糙度,可以降低磨粒磨损,且能使对磨的缸套试样较快地与之适配,从而促进了摩擦反应膜的形成和扩展,是摩擦因数和磨损量降低的主要原因.     

Tribological issues in reducing piston ring friction losses

In this paper improvement in fuel economy by reducing piston ring friction is studied and reduction of piston ring tension and the use of two-ring packages are found to be effective. However, these can be accompanied by adverse effects such as excessive wear and increasing oil consumption, and measures to overcome these problems are studied in detail.     

Influence of Surface Finishing on the Tribological Behavior of Self-Lubricating Iron-Based Composites

Recently, we presented the tribological evaluation of self-lubricating sintered steels produced by taking advantage of the powder injection molding process, the recently introduced plasma-assisted debinding and sintering process, and the in situ formation of solid lubricant particles. This new processing route promotes the in situ generation of nanostructured turbostratic graphite particles during silicon carbide dissociation. In this work, we present the influence of surface finishing on the tribological behavior of self-lubricating composites sintered at 1150°C with (3 and 5 wt%) and without SiC additions. We discuss the effects of the surface topography (R_a) on the friction coefficient and wear rates of specimens and counterbodies. The tribological behavior was analyzed using linear reciprocating sliding tests (constant load of 7 N, 60-min duration). It was shown that the reduction in surface roughness increased both the friction coefficients and wear rates of specimens and counterbodies, probably due to plastic deformation and consequent graphite reservoir sealing. Chemical analyses of the wear scars using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis showed a tribolayer that was composed predominantly of carbon and oxygen. Analyses of the wear scars showed traces of plastic deformation on both samples and counterbodies and the predominance of abrasion as the main wear mechanism.     

填充材料对聚四氟乙烯基复合材料摩擦学特性的影响

聚四氟乙烯基复合材料是重要的自润滑材料,应用广泛。根据填充材料的类别不同对聚四氟乙烯基复合材料进行了合理地分类,并阐述了不同填料对聚四氟乙烯基复合材料摩擦学特性的影响,分析和比较了不同填料的减摩抗磨机理,对于聚四氟乙烯基复合材料的科学研究和工程应用具有一定的借鉴和指导意义。