聚四氟乙烯碳纤维增强双马来酰亚胺复合材料的摩擦学性能

研究了不同含量PTFE碳纤维增强双马来酰亚胺复合材料的力学和摩擦学性能,并分析了在干摩擦和水润滑条件下的磨损表面形貌和磨损机制。结果表明:添加质量分数10%~15%PTFE的复合材料体系机械性能最佳,随PTFE含量的增加,复合材料的摩擦因数下降,而磨损率呈上升趋势。水润滑下,摩擦因数和磨损率比干摩擦下都有相应的降低。干摩擦下,材料的磨损主要以塑性变形、微观破裂及破碎为主;水润滑下,这一机制明显减弱,主要表现为微切削形态。     

Investigation of Tribological Properties of PI/FEP Laminated Composites Under Dry Sliding, Water- and Oil-Lubricated Conditions

Polyimide/fluorinated ethylene propylene (PI/FEP) laminated composites were fabricated by means of hot-press molding. The friction and wear behavior of high performance PI/FEP laminated composites has been comparatively evaluated under dry sliding, water- and oil-lubricated conditions. The worn surface morphologies of samples under different lubrication conditions were examined by scanning electron microscope and the wear mechanisms were comparatively discussed. As the results, PI/FEP laminated composites sliding against stainless steel under water lubrication registered lower friction coefficients, but higher wear rates than those under dry sliding. The friction coefficients and wear rates of samples under liquid paraffin-lubricated condition were lowest in three sliding conditions. The lateral surface of samples exhibited better wear resistance than parallel surface did under dry sliding.     

Friction and wear properties of UHMWPE/Al2O3 ceramic under different lubricating conditions

Friction and wear behavior of ultra-high molecular weight polyethylene (UHMWPE) sliding against Al₂O₃ ceramic under dry sliding, and lubrication of fresh plasma, distilled water and physiological saline were investigated with a self-made pin-on-disk apparatus at 37±1°C. The worn surfaces were examined with a scanning electron microscope (SEM). The results show that the friction behavior of UHMWPE is very sensitive to its water absorption state. The wear rate of UHMWPE under dry sliding is the highest and under plasma lubrication is the lowest. The wear mechanisms are different under dry friction and various lubricating conditions.     

Wear properties of Saffil/Al,Saffil/Al2O3/Al and Saffil/SiC/Al hybrid metal matrix composites

The purpose of this study is to investigate the wear properties of Saffil/Al, Saffil/Al₂O₃/Al and Saffil/SiC/Al hybrid metal matrix composites (MMCs) fabricated by squeeze casting method. Wear tests were done on a pin-on-disk friction and wear tester under both dry and lubricated conditions. The wear properties of the three composites were evaluated in many respects. The effects of Saffil fibers, Al₂O₃ particles and SiC particles on the wear behavior of the composites were elucidated. Wear mechanisms were analyzed by observing the worn surfaces of the composites. The variation of coefficient of friction (COF) during the wear process was recorded by using a computer. Under dry sliding condition, Saffil/SiC/Al showed the best wear resistance under high temperature and high load, while the wear resistances of Saffil/Al and Saffil/Al₂O₃/Al were very similar. Under dry sliding condition, the dominant wear mechanism was abrasive wear under mild load and room temperature, and the dominant wear mechanism changed to adhesive wear as load or temperature increased. Molten wear occurred at high temperature. Compared with the dry sliding condition, all three composites showed excellent wear resistance when lubricated by liquid paraffin. Under lubricated condition, Saffil/Al showed the best wear resistance among them, and its COF value was the smallest. The dominant wear mechanism of the composites under lubricated condition was microploughing, but microcracking also occurred to them to different extents.     

Tribological behavior between micro- and nano-crystalline diamond films under dry sliding and water lubrication

The tribological behavior of micro- and nano-crystalline diamond films is evaluated in dry sliding and water lubricating condition. The main wear mechanism is found to be abrasive wear mode induced by self-polishing. Non-diamond components and higher compressive residual stresses are detected in flat MCD films after dry sliding, in comparison to NCD. Origin of decreased friction coefficient in CVD diamond tribosystems under water lubrication is attributed to the effect of water on the formed graphic material and the chemisorbing of diamond surface with H₂O, hydrogen or hydroxyl ions. For the MCD/NCD or NCD/MCD contact, the surface roughness of ball largely determines the stable friction coefficient in dry sliding, where NCD film usually presents higher wear rate.     

青铜-石墨热喷涂层在干摩擦和水润滑条件下的摩擦磨损性能

在MM-200摩擦磨损试验机上研究了青铜-石墨热喷涂层在干摩擦和水润滑条件下的摩擦磨损性能,采用扫描电镜(SEM)对磨损表面形貌进行了观测和采用X射线能谱分析(XPS)分析了涂层成分。结果表明,在水润滑条件下涂层摩擦因数和磨损率均低于干摩擦条件下;在水润滑条件下磨损机制为轻微磨粒磨损和犁削磨损,在干摩擦下主要是较为严重的粘着磨损和犁削。这是由于水润滑降低了摩擦副界面温度,提高了石墨润滑膜的韧性,改善了润滑效果,从而阻止了粘着磨损的发生,水还促进了钢偶件表面致密氧化膜的形成,从而减轻磨损。因此水润滑对涂层磨损性能有较大影响。     

氧化锌晶须填充尼龙1010复合材料的摩擦磨损性能

采用模具挤压成型的方法制备了氧化锌晶须填充尼龙1010复合材料,使用纳米力学测试系统测试了不同含量氧化锌晶须复合材料的硬度和弹性模量,在UMT试验机上考察了复合材料的摩擦磨损性能,然后对磨损表面进行了SEM观察。结果表明：复合材料的硬度和弹性模量随氧化锌晶须含量的增加而增大;ZnOw在保持尼龙1010摩擦性能的同时,可使其耐磨性能提高60％左右。纯尼龙的主要磨损机制为粘着磨损和熔融,填充ZnOw后复合材料的磨损机制转变为疲劳剥层。     

Friction and Wear Behavior of CF/PTFE Composites Lubricated by Choline Chloride Ionic Liquids

The use of ionic liquids (ILs) as lubricants has received increasing attention in recent years. The use of ILs, however, is limited by the corrosion problem and their potential toxic property. Here we present the results of our initial study on the tribological properties of carbon fiber (CF)-filled polytetrafluoroethylene (PTFE) composites, which have an excellent chemical resistance property, lubricated by choline chloride ILs. The difference between choline chloride ILs and water and hydraulic oil as lubricants was studied at the same time, as was the effect of the anion on the lubricating property of choline chloride ILs. The worn surface and transfer film of CF/PTFE composites were studied by scanning electron microscopy. Our results indicate that the lubricating property of choline chloride ILs is much better than that of water and hydraulic oil. The friction coefficient and wear rate of CF/PTFE composites lubricated with ILs were approximately 60 and 50 % lower than those under the dry friction condition. Among the three kinds of ILs tested, the best tribological properties of the CF/PTFE composites were found for those sliding in the mixture of 1,2-propanediol and choline chloride. The worn surface and transfer film of CF/PTFE composites were also much smoother than those under the dry friction, water lubrication, and hydraulic oil lubrication conditions.     

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。     

不同润滑状态下炭纤维对锡青铜摩擦磨损性能的影响

短碳纤维增强锡青铜(碳/锡青铜)复合材料分别在干摩擦和有油滑状态下与钢进行了滑动对磨试验,研究了试验条件及碳纤维含量等因素对复合材料摩擦磨损性能的影响。试验结果表明,碳纤维对锡青铜摩擦磨损性能的影响行为与润滑状态有关,干摩擦时碳纤维的加入可以明显提高锡青铜的摩擦磨损性能,而有油润滑时碳纤维对锡青铜的摩擦磨损性能不仅没有改善,还会带来损害。     

干摩擦和水润滑条件下单晶硅的摩擦磨损性能研究

在UMT-2微摩擦试验机上,对单晶硅片进行了干摩擦和水润滑两种状态下的摩擦磨损试验,分析讨论了载荷和滑动速度对单晶硅片的摩擦因数和磨损率的影响规律;运用扫描电子显微镜,观察和分析了其磨损表面形貌。结果表明:干摩擦条件下的磨损机理主要表现为黏着磨损,水润滑条件下的磨损机理主要表现为机械控制化学作用下的原子/分子去除过程;水润滑条件下的摩擦因数和磨损量均较小,最小磨损率仅为10μm3/s;在水润滑条件下,载荷和滑动速度达到一定值时,硅片表面将发生摩擦化学反应,生成具有润滑作用的Si(OH)4膜,即机械作用在一定条件下对化学反应具有促进作用。     

粉末涂料固体润滑膜滚动/滑动复合干摩擦磨损特性研究

在M-2000磨损试验机上考察了经过一次处理和经两次处理的40Cr钢环表面喷涂3种粉末涂料型固体润滑膜(P型、H型、E型)试样,在线载荷为104N/m、相对滑动速度为0.042 m/s、干摩擦滚动/滑动复合磨损条件下的摩擦磨损性能,通过扫描电子显微镜(SEM)对试样磨损表面以及磨屑进行了显微观察。结果表明:底材经过一次处理(化学底膜处理)的复合固体润滑膜试样,P型和E型在磨损后期的摩擦因数分别稳定在0.38和0.32,而H型在0.40左右跳动;P型和H型的涂层磨损脱落期为60 m in左右,E型为120 m in左右;质量磨损从小到大顺序为P型相似文献   

Friction and wear properties of Kevlar pulp reinforced epoxy composites under dry sliding condition

In this work, the friction and wear properties of Kevlar pulp reinforced epoxy composites against GCr15 steel under dry sliding condition were evaluated on a reciprocating ball-on-block UMT-2MT tribometer. The effects of Kevlar pulp content on tribological properties of the composites were investigated. The worn surface morphologies of neat epoxy and its composites were examined by scanning electron microscopy (SEM) and the wear mechanisms discussed. The results show that the incorporation of Kevlar pulp into epoxy contributed to improve the friction and wear behavior considerably. The maximum wear reduction was obtained when the content of Kevlar pulp is 40 vol%. The friction coefficient of epoxy and its composites increased with load while increase in the sliding frequency induced a reverse effect. Fatigue wear and scuffing were notable for the neat epoxy. The fatigue cracks were greatly abated when the filler content was 40 vol%. The wear grooves appeared on the worn surface at higher filler content.     

碳酸酯对Ti6Al4V/钢摩擦副摩擦磨损性能的影响

采用SRV型微动摩擦磨损实验机分别考察了Ti6Al4V-钢摩擦副在2种碳酸酯润滑下的摩擦磨损性能,并利用扫描电子显微镜和X射线光电子能谱仪分析了Ti6Al4V磨斑表面形貌和典型元素的化学状态。结果表明,2种碳酸酯作为Ti6Al4V/钢摩擦副的润滑剂所表现出的减摩抗磨和承载能力优于其相对应的脂肪醇;载荷和频率明显影响Ti6Al4V/钢摩擦副在碳酸酯润滑下的摩擦磨损行为;碳酸二-2-乙基己酯所表现出的减摩抗磨和承载能力明显优于碳酸二辛酯;2种碳酸酯对Ti6Al4V/钢摩擦副的润滑机制为在Ti6Al4V磨损表面形成吸附膜,从而起到减摩抗磨的作用。     

Comparative study of micro- and nano-ZnO reinforced UHMWPE composites under dry sliding wear

This is a comparative study between ultra-high molecular weight polyethylene (UHMWPE) reinforced with micro-zinc oxide (ZnO) and nano-ZnO under different filler loads. These composites were subjected to dry sliding wear test under abrasive conditions. The micro- and nano-ZnO/UHMWPE composites were prepared by using a hot compression mould. The wear and friction behaviours were monitored using a pin-on-disc (POD) test rig. The pin-shaped samples were slid against 400 grit SiC abrasive papers, which were pasted, on the stainless steel disc under dry sliding conditions. The worn surfaces and transfer film formed were observed under the scanning electron microscope (SEM). Experimental results showed that UHMWPE reinforced with micro- and nano-ZnO would improve the wear behaviour. The average coefficient of friction (COF) for both micro- and nano-ZnO/UHMWPE composites were comparable to pure UHMWPE. The weight loss due to wear for nano-ZnO/UHMWPE composites are lower compared to micro-ZnO/UHMWPE and pure UHMWPE. The optimum filler loading of nano-ZnO/UHMWPE composites is found to be at 10 wt%. The worn surface of ZnO/UHMWPE composites shows the wear mechanisms of abrasive and adhesive wear. Upon reinforcement with micro- and nano-ZnO, the abrasive and adhesive wear of worn surfaces transited from rough to smooth.     

Effect of electrical current on the tribological behavior of the Cu-WS2-G composites in air and vacuum

As the traditional graphite-based composites cannot meet the requirement of rapid developing modern industry, novel sliding electrical contact materials with high self-lubricating performance in multiple environments are eagerly required. Herein a copper-based composite with WS2 and graphite as solid lubricant are fabricated by powder metallurgy hot-pressed method. The friction and wear behaviors of the composites with and without current are investigated under the condition with sliding velocity of 10 m/s and normal load of 2.5N/cm 2 in both air and vacuum. Morphologies of the worn surfaces are observed by optical microscope and compositions of the lubricating films are analyzed by XPS. Surface profile curves and roughness of the worn surfaces are obtained by 2205 surface profiler. The results of wear tests show that the friction coefficient and wear volume loss of the composites with current are greater than that without current in both air and vacuum due to the adverse effects of electrical current which damaged the lubricating film partially and roughed the worn surfaces. XPS results demonstrate that the lubricating film formed in air is composed of oxides of Cu, WS2 , elemental S and graphite, while the lubricating film formed in vacuum is composed of Cu, WS2 and graphite. Because of the synergetic lubricating action of oxides of Cu, WS2 and graphite, the composites show low friction coefficient and wear volume loss in air condition. Owing to the fact that graphite loses its lubricity which makes WS2 become the only lubricant, severe adhesive and abrasive wear occur and result in a high value of wear rate in vacuum condition. The formation of the lubricating film on the contact interface between the brush and ring is one of the factors which can greatly affect the wear performance of the brushes. The low contact voltage drop of the composites in vacuum condition is attributed to the high content of Cu in the surface film. This study fabricated a kind of new sliding electrical contact self-lubricating composite with dual-lubricant which can work well in both air and vacuum environments and provides a comprehensive analysis on the lubrication mechanisms of the composite.     

Friction and wear properties of bronze–graphite composite under water lubrication

Bronze–graphite composite was prepared using powder metallurgy. The friction and wear behaviors of the resulting composites in dry- and water-lubricated sliding against a stainless steel were comparatively investigated on an MM-200 friction and wear tester in a ring-on-block contact configuration. The wear mechanisms of the bronze–graphite composite were discussed based on examination of the worn surface morphologies of both the composite block and the stainless steel ring by means of scanning electron microscopy equipped with an energy dispersion spectrometry and on determination of some typical elements on the worn surfaces by means of X-ray photoelectron spectroscopy. It was found that the friction coefficient was higher under water lubrication than that under dry sliding and it showed margined change with increasing load under the both sliding conditions. A considerably decreased wear rate of the bronze–graphite composite was registered under water-lubricated sliding than under dry sliding, though it rose significantly at a relatively higher load. This was attributed to the hindered transfer of the composite onto the counterpart steel surface under water-lubricated sliding and the cooling effect of the water as a lubricant, while its stronger transfer onto the steel surface accounted for its higher wear rate under dry sliding. Thus, the bronze–graphite composite with much better wear-resistance under water-lubricated sliding than under dry sliding against the stainless steel could be a potential candidate as the tribo-material in aqueous environment.     

微米氧化铝/尼龙复合材料在不同条件下的滚滑摩擦磨损行为研究

以微米氧化铝(Al2O3)为增强剂,尼龙1010为基体,进行氧化铝/尼龙复合材料在干摩擦和水润滑条件下的滚滑动摩擦磨损实验。通过实验发现,水能降低氧化铝/尼龙复合材料的摩擦因数,但增大了磨损量。水润滑时,尼龙1010材料的摩擦因数为0.09,为干摩擦时的45%;氧化铝/尼龙复合材料的平均摩擦因数为0.1195,比尼龙增加了24.7%,是干摩擦时的42%。水润滑时尼龙1010的磨损量为干摩擦时的2.5倍,复合材料平均磨损量为干摩擦时2.8倍。     

润滑条件对纳米SiO2填充尼龙复合材料摩擦学性能的影响

利用MM-200磨损实验机在干摩擦、水润滑和油润滑等条件下，研究了润滑条件对含量为10％的纳米SiO2填充尼龙1010复合材料与45^#钢对磨时的摩擦学性能的影响，并利用扫描电子显微镜对纳米SiO2-PA1010复合材料的磨损表面和磨损机理进行了观察和分析。结果表明水润滑时，纳米SiO2-PA1010复合材料的摩擦因数比在干摩擦时有一定程度的降低，但磨损量却比干摩擦时增加了很多；而在油润滑时，摩擦因数和磨损量均比干摩擦和水润滑时降低了许多；复合材料的磨损机制也随着润滑条件的不同发生了相应的变化。     

聚四氟乙烯填充含量对钢背超高分子量聚乙烯纤维织物复合材料摩擦学性能的影响

为改善广泛应用于船舶苛刻环境无油/脂润滑摩擦配副材料的摩擦学性能,将聚四氟乙烯（PTFE）按不同质量分数与钢背超高分子量聚乙烯纤维织物复合材料结合,研究它与45钢盘在变转速环环端面干摩擦状态下的摩擦学特性。对试验过程中摩擦因数及磨损量进行测量,利用表面轮廓仪、扫描电子显微镜与超景深显微镜对复合材料及对磨件磨损表面形貌进行了观察与分析。结果表明：所有填充PTFE的复合材料摩擦学性能均表现优异,随着PTFE含量的增加,复合材料摩擦性能变差,其中1 %（质量分数） PTFE填充复合材料综合摩擦性能最好,在试验工况下主要发生磨粒磨损,PTFE填充量较高的复合材料在高速下由于团聚及摩擦热量积聚主要经历黏着磨损与疲劳磨损。