均匀设计法在聚醚醚酮复合材料摩擦学特性试验中的应用研究

采用均匀设计法设计了CF/SiO2/PTFE/PEEK复合材料,并模压成型;在摩擦磨损试验机上研究了PEEK复合材料的摩擦学特性,应用回归分析法对其摩擦学特性试验数据进行了分析,得到了摩擦学特性参数的回归公式。结果表明,均匀设计法应用于PEEK复合材料的摩擦学特性研究是可行的,能有效预测复合材料的摩擦学特性参数,回归分析结果与复合材料的摩擦磨损试验数据相吻合。     

往复压缩机密封件及摩擦磨损研究进展

在往复压缩机的使用过程中,气阀、活塞环、填料环等密封件起到关键的密封作用,保障了压缩气体的稳定。密封件的耐磨程度,决定着泄漏量的大小,也直接关系着产品的性能。近年来,人们对密封件的常用材料——聚四氟乙烯(PTFE)、聚醚醚酮(PEEK)及其复合材料,进行了深入的摩擦学研究,取得了大量的研究成果。在介绍往复压缩机原理和密封件的基础上,对往复压缩机所用PTFE、PEEK及其复合材料的摩擦学研究进行综述,为今后往复压缩机密封件摩擦学研究提供帮助。     

固体润滑高分子涂层材料研究进展

固体润滑材料已经成为摩擦学研究的热点之一。本文介绍了高分子基涂层材料研究发展和应用研究状况,综述了聚苯硫醚(PPS)、环氧树脂、聚酰亚胺(PI)、聚四氟乙烯(PTFE)、聚醚醚酮(PEEK)作为固体润滑材料的研究应用进展。     

聚醚醚酮/聚四氟乙烯复合水润滑轴承材料性能研究

采用热模压工艺制备聚醚醚酮/聚四氟乙烯(PEEK/PTFE)复合材料,研究PTFE对复合轴承材料拉伸强度、邵氏硬度和摩擦学性能的影响。结果表明:随着PTFE含量的增加,摩擦因数显著降低,延长了轴承材料寿命。当PTFE含量为5%时,复合材料的拉伸强度为93 MPa,邵氏硬度为83,摩擦因数为0.19,磨损量为0.072mm3,综合性能最佳,满足水润滑轴承材料在力学、吸水性、长寿命等方面的要求。     

碳化硅陶瓷与聚醚醚酮复合材料的摩擦磨损特性研究

研究了碳化硅(SiC)陶瓷/聚醚醚酮(PEEK)复合材料摩擦副在干摩擦和水润滑条件下的滑动摩擦磨损行为,并分析了载荷和水润滑条件对SiC/PEEK摩擦副摩擦因数和耐磨性的影响。结果表明:干摩擦条件下,摩擦因数随时间的增加逐渐趋于稳定直至试验结束,载荷越大,达到稳定摩擦状态所需要的时间越短;水润滑条件下,由于水的存在,改善了SiC/PEEK摩擦副的边界润滑条件,同时水起到了冷却作用,因此载荷对摩擦因数的影响不大。     

PEEK复合材料及其在风电滑动轴承中的应用

围绕聚醚醚酮(PEEK)复合材料在滑动轴承中的应用，阐述了PEEK材料的耐磨性、耐高温性、材料相容性等综合性能，总结了表面改性、纤维增强、颗粒填充及聚合物共混等改性方法；分析滑动轴承出现胶合、划伤等故障的原因，提出PEEK复合材料摩擦磨损性能研究的必要性；对比PEEK复合材料各成型方法的成型效率、制品强度，分析了注塑成型、热压成型、模压成型、缠绕成型等成型方法的优缺点；基于自润滑聚合物复合材料与金属基底结合机理，对比了采用机械互锁法、化学键法、添加增强体及激光处理获得结合界面的剪切强度；结合PEEK复合材料在压缩机、水泵、磁力泵、高温机械等设备中的应用，探讨了PEEK复合滑动轴承在风电领域应用的可行性，指出后续应以服役性能为目标，结合智能维护、寿命预测等技术，开展PEEK复合滑动轴承的设计与研发。     

模拟矿井环境下的PEEK/SiO2/CF-MoS2复合材料摩擦行为研究*

为改善聚醚醚酮（PEEK）在矿井工况下的摩擦性能,选用纳米二氧化硅（SiO2）、二硫化钼（MoS2）和短切碳纤维（CF）为增强填料制备PEEK/SiO2/CF-MoS2复合材料,并探究PEEK/SiO2/CF-MoS2复合材料在不同工况条件下的滑动与滚动摩擦学性能;通过模拟滚轮罐耳在矿井环境下的运行方式,分析其磨损形貌和磨损机制。结果表明：PEEK/SiO2/CF-MoS2复合材料在不同载荷条件下均具有良好的减摩和耐磨特性;滑动摩擦在水介质工况下及滚动摩擦在干摩擦工况下,复合材料的摩擦因数和磨损率最低,其磨损机制均以磨粒磨损为主。与矿井常用的聚氨酯材料的对比,PEEK/SiO2/CF-MoS2复合材料的摩擦学性能更为优异。     

聚醚醚酮填充聚四氟乙烯摩擦学性能

采用共混-冷压-烧结的工艺制备聚醚醚酮（PEEK）填充聚四氟乙烯（PTFE）复合材料,考察 PEEK 含量对 PTFE /PEEK 复合材料的力学性能和摩擦学性能的影响,用扫描电子显微镜（SEM）观察其磨损表面和对偶表面形貌,并探讨磨损机制。结果表明：复合材料的拉伸强度随着 PEEK 含量的增加而降低,在一定范围内,冲击强度随着PEEK 含量的增加而增大;随着 PEEK 含量的增多,摩擦因数呈现先减小后增大的趋势,体积磨损率则逐渐减小。当PEEK 质量分数为20％时,复合材料耐磨性较纯 PTFE 提高了近700倍,其原因在于 PEEK 的加入改变了磨屑形成机制,并能形成均匀连续的转移膜,进而降低了磨损。     

石墨填充聚四氟乙烯基复合材料的摩擦学性能

为了研制PTFE基粘弹-摩擦型阻尼材料,采用机械共混-冷压成型-烧结的工艺制备了石墨、聚苯硫醚、聚醚醚酮混合填充PTFE基复合材料,利用环-块式磨损试验机,在干摩擦条件下考察了复合材料的摩擦学性能,并用扫描电镜观察了磨损表面形貌,研究了复合材料的磨损机制。结果表明:PTFE含量不同的复合材料,随石墨填充量的增大,摩擦因数和磨损率的变化趋势不同,磨损主要由犁削、粘着和疲劳剥落中的一种或几种引起;适当配比的PTFE基复合材料具有较好的摩擦阻尼性能,能够满足粘弹-摩擦阻尼材料的要求。     

CF/PEEK复合材料自阻电热-原位膜混合加热固化方法

碳纤维增强聚醚醚酮树脂基(CF/PEEK)复合材料密度小、韧性强、疲劳强度高,且可循环使用,但PEEK树脂熔融温度高(>340℃)、熔融黏度大(>1000 Pa·s)、熔融-烧蚀工艺温度窗口小,零件固化难度大。提出一种CF/PEEK树脂基复合材料自阻电热-原位膜混合加热固化方法,结合有限元仿真,引入组合原位膜自适应地辅助加热制件。有限元仿真和实验研究结果证明了该方法的有效性：加热过程中相较纯自阻电热加热方法,制件温度均匀性提高了75%,结晶度提高了16.2%,实现了CF/PEEK树脂基复合材料的高效、均匀加热固化。     

GF/PTFE自润滑纤维复合材料磨损性能热衰退研究

针对高频摆动关节轴承摩擦热对自润滑纤维复合材料摩擦磨损性能的影响,研制了高频使用条件下的玻璃纤维增强聚四氟乙烯(GF/PTFE)自润滑纤维复合材料,利用MYB～500高频高载摆动摩擦磨损试验机,对其进行不同摩擦温度下的摩擦磨损性能测试,研究摩擦热作用下材料自润滑性能和磨损性能衰退特征,分析磨损产物和摩擦表面以及不同摩擦温度下材料的磨损机理。结果表明,摩擦热对材料自润滑性能影响显著,适当的摩擦温度范围能够保证材料的自润滑性能,摩擦温度和摩擦因数之间互为耦合作用,对材料的磨损性能具有一定的影响;高摩擦热作用于自润滑过程及机理的改变,造成材料的磨损性能衰退现象。因此,不同温度下材料的磨损特征具有明显的差异化,其中低摩擦温度下(60～120℃)材料自润滑性能优异,磨损率很低;140℃摩擦温度条件下材料摩擦磨损性能开始衰退;材料在高摩擦温度下(140～180℃)的磨损初期自润滑性能良好、磨损轻微,而中后期磨损严重。微观分析表明,低摩擦温度下材料的磨损机理以轻微粘着和疲劳磨损为主;高摩擦温度下材料的磨损以片状剥落、纤维剪切破坏为主,且磨损面局部损伤特征明显,磨损严重。     

Correlation of the tribological behaviors with the mechanical properties of poly-ether-ether-ketones (PEEKs) with different molecular weights and their fiber filled composites

The tribological behaviors of three poly-ether-ether-ketones (PEEKs) with different molecular weights and their SCF (short carbon fiber)/graphite/PTFE (polytetrafluoroethylene) filled composites were examined using a block-on-ring apparatus under dry sliding conditions. Tensile tests, hardness measurements and dynamic mechanical thermal analysis (DMTA) of the PEEK based materials were also performed. The tribological behaviors of PEEK based materials were correlated with their mechanical properties and the tribological mechanisms were discussed based on scanning electron microscope (SEM) inspections of worn surfaces and wear debris. Under a low apparent pressure, a high material ductility seems to reduce the wear rate of pure PEEK through alleviating the microcutting effect exerted by the protruding regions of the counterpart. Under a high pressure, however, a high stiffness seems to improve the wear resistance of pure PEEK by reducing the plastic flow occurring in the PEEK surface layer. After incorporating SCF/graphite/PTFE fillers, the wear rate of PEEK was decreased significantly. Thinning and cracking of SCF are supposed to be the important factors determining the tribological behaviors of the composites.     

Tribological behaviors of hierarchical porous PEEK composites with mesoporous titanium oxide whisker

Hierarchical porous PEEK self-lubricating composites were prepared by mold-leaching and vacuum melting process under high temperature. The tribological behaviors were investigated for the porous PEEK composite and the porous composite after incorporating micro-porogen (NaCl) and mesoporous titanium oxide whiskers. If only micro-porogen was incorporated, the lowest steady state specific wear rate was observed for PEEK composites filled with 30% NaCl. Based on this porous PEEK composite, the effects of mesoporous titanium oxide whiskers and non-perforated titanium oxide whiskers on the friction and wear properties of PEEK composites were studied. Results showed that nano-micro porous PEEK composites with 30 wt% micro-porogen and 5 wt% mesoporous titanium oxide whiskers reached the lowest friction coefficient and specific wear rate, which were recorded as 0.0194 and 2.135×10^–16 m³/Nm under the load of 200 N. Compared with 15 wt% carbon fiber-reinforced PEEK composite which is widely used in industry, the wear resistance of the designed hierarchical porous PEEK composite increased by 41 times, showing outstanding wear resistance.     

Role of different metallic fillers in non-asbestos organic (NAO) friction composites for controlling sensitivity of coefficient of friction to load and speed

Sensitivity of μ (coefficient of friction) of friction composites towards load and speed is composition specific. For an ideal friction material, it should be zero. It was of interest to examine the influence of increasing amount of three commercially popular metallic fillers (steel fiber, brass fiber and copper powder) on the tribological performance of friction composites including sensitivity of μ towards load and speed. Three series of non-asbestos organic (NAO) friction composites comprising of seven composites in the form of brake pads were developed in the laboratory using three metallic fillers as a single variant. All composites were characterized for physical, chemical and mechanical properties. These were further tribo-tested on reduced scale prototype (RSP) for friction, wear and sensitivity of friction coefficient (μ) towards load and speed characteristics. It was concluded that inclusion of metal contents led to enhancement in friction performance of the composites but at the cost of wear resistance, in general. From μ sensitivity point of view, composites with higher metallic contents and hence thermal conductivity (TC) showed better performance. Overall it was observed that copper powder based composite (with 10%) proved as the best performer from both friction and wear point of view.     

On sliding friction and wear of polyetheretherketone (PEEK) composites at elevated temperatures

The friction and wear behaviour of polyetheretherketone (PEEK) composites, incorporating different amounts of short carbon fibres with different surface treatments, was studied under dry sliding conditions against smooth steel on a pin-on-disc apparatus at different temperatures. Wear of the composites was reduced considerably in all cases, but, whatever the surface treatment, wear increased with increasing temperature for all proportions off fibres. For minimum friction coefficient there was an optimum proportion of fibre volume fraction of about 10 vol.%. The effect of the fibre surface treatment was not significant for the tribological behaviour of the PEEK composites. To predict wear performance, a wear model proposed by Friedrich and Voss seemed to work properly, and, furthermore, a friction model was developed to predict the friction behaviour of PEEK composites with short carbon fibres.     

Tribological Behavior of PTFE Composites Filled with PEEK and Nano-Al2O3

In this study, the tribological properties of polytetrafluoroethylene (PTFE) composites filled with polyetheretherketone (PEEK) and nano-Al₂O₃ particles were studied using a block-on-ring wear tester. The tribological performance of the composites was affected by the experimental parameters (sliding speed, normal load, and environmental temperature) and the composites achieved a high-speed sliding friction state. The results showed that the PEEK and nano-Al₂O₃ particles significantly improved the wear resistance of the PTFE composites. In addition, the nano-Al₂O₃ particles increased the hardness of the composites and enhanced the mechanical properties to enable applications in a wider range of industrial fields. The effects of the sliding speed and normal load on the tribological properties were more significant than that of the environmental temperature. In addition, the entire wear process was divided into three stages (the initial wear stage, severe wear transition stage, and ultralow stable wear stage), according to the evolution of the tribological characteristics (wear rate, morphology of the worn surface and transfer film, and wear debris morphology).     

Lubrication of polyether ether ketone (PEEK) surface by liquid ultrathin films for high wear durability

PEEK, an engineering polymer with many advantages such as lightweight, high thermal stability, high strength coupled with toughness, has often been used as a substitute for metals in applications such as bearings, piston parts, pumps and even biomaterials. However, it shows high coefficient of friction which results in high wear rate when used in tribological applications. This paper seeks to solve tribological problems of high friction and wear for PEEK by applying an ultrathin layer of perfluoropolyether (PFPE) and Multiply-Alkylated Cyclopentane (MAC) lubricants on the surface of PEEK. Results obtained from tribological tests conducted showed that for highly improved tribological performance, there is an optimal initial surface roughness of PEEK surface and lubricant concentration or the thickness of the coatings for both PFPE and MAC lubricant. Also, MAC performs better compared to PFPE for thinner films.     

纳米表面工程与摩擦学

利用表面工程技术解决摩擦磨损问题具有高效、实用等特点。随着科学技术的迅速发展，纳米材料和纳米技术在表面工程中得到了广泛应用，由此出现了“纳米表面工程”。利用纳米表面工程技术制备的涂层和镀层有着非常优异的摩擦学性能。本文叙述了作者近年来的有关工作，包括热喷涂纳米陶瓷涂层、热喷涂纳米自润滑涂层、纳米陶瓷／聚合物复合涂层、纳米复合电镀层以及纳米电泳沉积层的摩擦磨损特性和机制。     

Tribological studies of poly(ether ether ketone) blends

A review of friction and wear studies of poly(ether ether ketone) (PEEK) blended with other polymers is presented. PEEK is a high performance thermoplastic now commonly employed in many engineering applications, but its tribological properties deteriorate in high temperature environments. One approach to improving the friction and wear properties of PEEK is to blend this plastic with appropriate polymers. In recent years, a number of investigations into the tribology of PEEK blended with poly(ether imide) (PEI), polytetrafluoroethylene (PTFE) and liquid crystalline polymers (LCPs) have been reported and these studies are discussed.