铜锡铅锌合金的摩擦磨损性能

利用MMU-200型摩擦磨损试验机研究了铜锡铅锌合金与GCr15钢对磨时的摩擦磨损特性,利用扫描电子显微镜对合金的磨损表面形貌进行了观察。结果表明:铜锡铅锌合金的磨损率随载荷和摩擦速度的增加而增大;其摩擦因数随摩擦速度的增加而减小,随载荷的增加先增大后减小;其磨损机制主要为磨粒磨损和粘着磨损;合金中的铅相起到了润滑作用,有利于提高合金的耐磨性能。     

含石墨转移层对铜－二氧化硅／ 钢摩擦磨损行为的影响

为探讨干摩擦磨损条件下含石墨转移层对摩擦磨损性能的影响,在45#钢表面覆盖含石墨润滑层,通过干滑动磨损试验,研究含石墨润滑层对钢/铜-二氧化硅摩擦副摩擦因数、磨损量及摩擦损（亚）表面的影响。结果表明：与无石墨润滑层的45#钢相比,含石墨润滑层的45#钢的摩擦因数、磨损率明显下降,且干滑动试验后磨损表面相对光滑平整,表明含石墨摩擦层起到了减摩降磨作用,抑制了金属的直接接触。     

高能电子辐照对PTFE填充酚酞聚芳醚酮复合材料摩擦磨损性能的影响

用MM-200型摩擦磨损试验机考察了辐照对PTFE填充酚酞聚芳醚酮复合材料的摩擦磨损性能的影响。结果表明：PEK-C复合材料经辐照后其磨擦磨损性能变差。电镜分析表明,辐照样品的磨屑大于未辐照后样品的磨屑。辐照样品的磨损表面梨沟较明显,而未辐照样品的磨损表面无犁沟槽,且表面比较光滑,而电子探针微区分析EPMA表明,辐照样品与钢环对磨后,其摩擦表面较粗糙,钢环表面没有形成连续、均匀的转移膜;而未辐照样品与钢环对磨后,它们的摩擦表面较光滑,钢环表面均形成了较连续、均匀的转移膜。     

选择性激光熔化技术制备的Cu-10Sn合金的载流摩擦学性能

为提高Cu-10Sn合金接触线的力学及载流摩擦学性能,利用选择性激光熔化（SLM）技术制备Cu-10Sn合金,分析Cu-10Sn合金的组织结构及硬度等,研究不同载荷和电流对Cu-10Sn合金的载流摩擦学行为的影响;利用扫描电子显微镜对摩擦表面进行微观分析,揭示其磨损机制。试验结果表明：与载荷为10 N时相比,30 N时摩擦副的平均摩擦因数增大,接触电阻和电弧能量降低,磨损加剧;Cu-10Sn合金与GCr15球对摩,合金表面被氧化,铜元素被转移并粘附于对摩球上形成黏着磨损;与纯机械摩擦行为相比,载流条件下Cu-10Sn合金表面磨痕加深,黏着物、氧化物的数量明显增加,摩擦因数和磨损体积发生显著变化;小载荷小电流下磨痕表面出现电弧烧蚀现象;而电流为10 A时,磨损表面形成的氧化膜的润滑作用,减缓了材料的磨损。在无电流条件下磨损机制主要为疲劳磨损和黏着磨损;而在载流条件下,电化学氧化和黏着磨损显著增强。研究结论为SLM技术制备的铜锡合金应用于接触线等电传导接触材料提供参考。     

倾斜板铸造不同成分铝铅耐磨合金的摩擦磨损性能

采用倾斜板铸造技术制备了铝铅合金,并用扫描电子显微镜对磨擦表面的形貌和成分等进行了观察与分析,研究了合金的基本特性和不同合金元素对摩擦学性能的影响,探讨了干摩擦条件下铝铅合金与45钢对摩时的磨损机理。结果表明:与铝合金基体相比,作为软相铅、锡的加入使铝铅合金的摩擦因数降低了15%,磨损量减小了近70%;随着锡含量的增大,其摩擦因数和磨损质量呈现先减小后增大的趋势;铝铅合金的摩擦学性能优良,其磨损形式为轻度的粘着磨损、磨粒磨损和疲劳磨损的复合磨损。     

滑动速度对铜－石墨摩擦层形成、转移及失效的影响

以铜-石墨/45#钢为研究对象,研究大气、干滑动条件下,滑动速度对铜-石墨摩擦层的形成、转移和失效的影响。低速条件下,铜-石墨磨损表面平滑、致密,而高速条件下磨损表面粗糙、松散。铜-石墨在45#钢表面微凸体的切削作用下脱落,一部分形成片状磨屑,另一部分单向转移至45#钢表面形成含铜-石墨的摩擦层。摩擦速度的提高,使铜-石墨摩擦层难于在磨损表面有效形成,加速了其脱落的进程,从而降低了其减摩能力。     

纳米锌填充超高分子量聚乙烯复合材料微动摩擦磨损性能

利用热压烧结法制备不同含量纳米锌填充超高分子量聚乙烯(UHMWPE)复合材料,采用微动摩擦磨损试验机研究干摩擦条件下纳米锌含量对复合材料微动摩擦磨损性能的影响。利用场发射扫描电子显微对复合材料断面进行分析,采用扫描电子显微镜对材料磨损表面及钢球进行表征,探讨复合材料的磨损机制。研究结果表明:随着纳米Zn含量的增加,复合材料的摩擦因数和磨损率均表现为先降低后升高;当纳米Zn质量分数为1%时复合材料具有最低的摩擦因数和磨损率,且对偶钢球表面形成连续的转移膜;复合材料的磨损机制主要为黏着磨损和磨粒磨损。添加锌纳米颗粒,可以提高UHMWPE复合材料的微动摩擦磨损性能,当纳米锌质量分数为1%时,复合材料具有最低的摩擦因数和最优的耐磨损性能。     

类金刚石膜在水环境下的摩擦学行为

测试了 CoCrMo合金表面沉积类金刚石薄膜与CoCrMo在水溶液润滑下的摩擦磨损行为。结果表明：摩擦副在不同浓度牛血清白蛋白溶液润滑下的平均摩擦因数均在0.10左右,CoCrMo合金销磨损量最小值为1.69×10-5 mm3;相同条件下,生理盐水溶液润滑的磨损量为1.38×10-5 mm3,且销表面有转移膜生成;牛血清白蛋白溶液润滑时,界面蛋白吸附层屏蔽了转移膜的形成。根据结果可知,转移膜的形成经历了磨屑附着、连续转移、局部脱落的过程。     

尼龙6/蒙脱土纳米复合材料的摩擦学特性及磨损机理

用熔融插层法制备了不同蒙脱土含量的尼龙6/蒙脱土纳米复合材料,并与45钢进行了环块对磨试验.结果表明：该材料与45钢对磨的摩擦因数随有机蒙脱土含量的增加而减小;纯尼龙6和2%有机蒙脱土复合材料的磨损属于机械和粘着磨损;4%有机蒙脱土复合材料的磨损属于疲劳磨损;6%和8%有机蒙脱土复合材料的磨损以机械磨损为主;10%蒙脱土复合材料的磨损主要以疲劳磨损为主.     

碳/碳复合材料的载流摩擦磨损性能及机理

在高速载流摩擦磨损试验机上对碳/碳复合材料进行摩擦磨损试验,研究了不同电流、载荷和滑动速度下复合材料的摩擦因数、磨损率及磨损表面形貌,并分析了磨损机理。结果表明:在一定载荷作用下,随电流和滑动速度增大,碳/碳复合材料的摩擦磨损性能先保持良好而后趋于恶化;在电流和滑动速度一定的条件下,较低和较高的载荷都会恶化碳/碳复合材料的摩擦磨损性能;随着摩擦表面温度升高,碳/碳复合材料基体开始氧化流失,碳纤维脱落形成磨屑,从而导致磨粒磨损;随后摩擦表面的高温使磨屑软化,磨屑在机械应力作用下逐渐被碾压成碳膜,形成粘着磨损;磨损表面温度的进一步升高以及高速冲击的作用破坏了碳膜的完整性,从而恶化了碳/碳复合材料的摩擦磨损性能。     

Dry sliding friction and casing wear behavior of PCD reinforced WC matrix composites

The friction and casing wear properties of PCD reinforced WC matrix composites were investigated using a cylinder-on-ring wear-testing machine against N80 casing steel counterface under dry sliding conditions. The results indicate that the friction and casing wear rate of PCD reinforced WC matrix composites are the lowest among the materials. As the applied load and sliding speed steadily increase, the friction coefficients of PCD reinforced WC matrix composites decrease. In addition, the casing wear rates increase with increasing load, but decline with sliding velocity. The dominant wear mechanism of the PCD composite is the micro-cutting wear, accompanied by adhesive wear.     

Sliding wear behavior of planar random zinc-alloy matrix composites

The friction and wear behavior of planar random zinc-alloy matrix composites reinforced by discontinuous carbon fibres under dry sliding and lubricated sliding conditions has been investigated using a block-on-ring apparatus. The effects of fibre volume fractions and loads on the sliding wear resistance of the zinc-alloy matrix composites were studied. Experiments were performed within a load range of 50–300 N at a constant sliding velocity of 0.8 m s⁻¹. The composites with different volume fractions of carbon fibres (0–30%) were used as the block specimens, and a medium-carbon steel used as the ring specimen. Increasing the carbon fibre volume fraction significantly decreased the coefficient of friction and wear rates of both the composites and the medium-carbon steel under dry sliding conditions. Under lubricated sliding conditions, however, increasing the carbon fibre volume fraction substantially increased the coefficient of friction, and slightly increased the wear of the medium-carbon steel, while reducing the wear of the composite.Under dry sliding conditions, an increasing load increased not only the wear rates of both the composite and the unreinforced zinc alloy, but also those of their corresponding steel rings. However, the rate of increase of wear with increasing load for both the composite and its corresponding steel ring was much smaller than for the unreinforced zinc alloy and its corresponding steel ring. The coefficient of friction under dry sliding conditions appeared to be constant as load increased within a load range of 50–150 N for both the composite and the unreinforced zinc alloy, but increased at the higher loads. Under any load the coefficient of friction of the composite was lower than half that of the unreinforced zinc alloy under dry sliding conditions.     

碳化硼增强铝基复合材料的摩擦磨损性能

为了比较两种含量不同的碳化硼颗粒增强铝基复合材料的摩擦学性能,将其加工成销试样,在多功能摩擦磨损试验机上分别与钢盘试样进行对比摩擦磨损试验,重点研究了接触载荷和相对滑动速度对两种复合材料摩擦磨损性能的影响.结果表明:碳化硼增强铝基复合材料的磨损量随载荷与相对滑动速度的增大而增大,而摩擦因数随载荷与相对滑动速度的增大而减小,较高碳化硼含量的复合材料的耐磨性能比较低含量的复合材料好.     

纳米和微米SiO2颗粒对PPESK复合材料摩擦学性能的影响

用热压成型法制备了纳米、微米SiO2填充聚醚砜酮(PPESK)复合材料，考察了复合材料的硬度和抗弯强度，并研究了干摩擦条件下纳米、微米SiO2颗粒对复合材料摩擦磨损性能的影响，用扫描电镜观察分析了复合材料磨损表面形貌及磨损机理。结果表明：干摩擦条件下，纳米SiO2填充PPESK主要是轻微的磨粒磨损；而微米SiO2填充PPESK主要是严重的磨粒磨损。     

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 of polyphenylene sulfide composites filled with micro and nano CuO particles in water-lubricated sliding

The tribological behavior of polyphenylene sulfide (PPS) composites filled with micro and nano CuO particles in water-lubricated sliding condition were studied. Pin-on-disk sliding tests were performed against a steel counterface of surface roughness 0.09–0.11 μm. The lubrication regimes were established from friction data corresponding to various combinations of loads and sliding speeds. Later experiments were performed using the sliding speed of 0.5 m/s and contact pressure of 1.95 MPa, which corresponded to boundary lubrication regime. Micro CuO particles as the filler were effective in reducing the wear of PPS but nano CuO particles did not reduce wear. The steady state wear rate of PPS-30 vol.% micro CuO composite was about 10% of that of unfilled PPS and the coefficient of friction in this case was the lowest. The examination of the topography of worn pin surfaces of nano CuO-filled PPS by SEM revealed grooving features indicating three-body abrasion. The transfer films formed on the counterfaces during sliding were studied by optical microscopy and AFM. The wear behavior of the composites in water-lubricated sliding is explained using the characteristics of worn pin surfaces and transfer films on the counterface.     

Tribological behaviour of PTFE modified cotton polyester composites

Abstract

An attempt on modification of tribological behaviour of cotton polyester composite was done with polytetrafluoroethylene (PTFE). PTFE modified polyester–cotton composites were developed and studied for their friction and sliding wear behaviour at different applied loads. The sliding wear tests of composites were conducted against EN-31 steel counter face. The coefficient of friction μ as well as the sliding wear rate of cotton–polyester composites reduced significantly on addition of PTFE. The reduction in wear rate of PTFE modified polyester–cotton composite has been discussed with the help of SEM observations of worn surfaces and coefficient of friction.     

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.     

Dry-Sliding Tribological Properties of Bronze–Graphite Composites

Bronze-uncoated and nickel-coated graphite composites were fabricated by powder metallurgy route. The tribological behaviors of composites sliding against AISI52100 steel ball under dry sliding condition were studied using a ball-on-disk tribometer. The nickel-coated graphite composites showed much better tribological properties in comparison with bronze and uncoated graphite composite. The friction coefficient of nickel-coated graphite composites decreased with increasing nickel-coated graphite content. However, the specific wear rate increased with the increase in nickel-coated graphite. The composite containing 15?wt% nickel-coated graphite showed the best self-lubricating properties because the compacted and stable mechanical mixed layer was formed on the worn surfaces. The wear mechanism of bronze 663 is adhesive wear and abrasive wear. The uncoated nickel-coated graphite composite shows the adhesive wear and delamination characteristics. However, the wear mechanism of nickel-coated composites is mildly abrasive wear.     

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.