干摩擦条件下表面成膜添加剂的应用研究

本文以制动摩擦副为例，讨论了在摩阻材料中添加含氟、硫或铜元素的化合物时，与金属对偶件在干摩擦条件下其表面膜的形成机理，探讨了不同成膜添加剂对摩阻材料的摩擦磨损特性的影响。试验表明：含硫的成膜剂，可减少对偶件表面的磨损，但不利于稳定摩擦系数；而添加含氟和铜化合物的成膜剂，既利于减少对偶件表面的磨损，又可提高摩擦的稳定性。文中提出了在干摩擦条件下，在摩阻材料中添加表面成膜剂是控制或稳定摩擦系数及减少磨损的重要途径，并在实践中得到了验证。     

SiCp增强铝基复合材料与Kevlar增强摩擦材料摩擦副摩擦磨损机理研究

采用盘销式摩擦磨损试验机，对SiCp含量为20vol％的铝基复合材料和Kevlar增强摩擦材料组成的摩擦副在于摩擦条件下的摩擦磨损机理进行了实验研究。结果表明：摩擦副在跑合过程中，铝基复合材料中的SiCp颗粒对较软的有机复合材料产生犁削和微观切削效应，磨损机理为铝基复合材料的硬质颗粒对较软的有机复合材料的磨粒磨损；在跑合后的磨损试验中，摩擦材料磨损表面呈现出粘着磨损和塑性变形特征，随着转动速度的增加，塑性流动加剧；摩擦副接触表面发生材料的相互转移，并在铝基复合材料表面形成转移膜，且在较高速度下转移膜更易形成；在高速条件下，摩擦材料表面可见从铝基复合材料的铝合金基体中脱离的SiCp颗粒和熔融迹象；摩擦材料的磨损机理主要为磨粒磨损、粘着磨损和塑性变形。     

无油压缩机气缸-活塞环摩擦磨损特性试验研究

为探究无油压缩机气缸与填充PTFE活塞环的配对摩擦磨损特性，在Rtec-instruments多功能摩擦磨损试验机上对不同表面处理工艺的不锈钢、铝合金气缸材料与不同配方填充PTFE活塞环材料进行配对摩擦磨损试验。通过对摩擦系数时序曲线的变化规律、摩擦副磨损前后表面形貌特征及填充PTFE磨损量的研究，选择最优摩擦学性能的气缸-活塞环的配对摩擦副。结果表明，铝合金与不锈钢表面进行PCVD处理相对于常规阳极氧化和镀铬更易在摩擦表面形成自润滑转移膜；PTFE填充碳纤维时，其摩擦系数时序曲线随磨合过程降低且较为稳定；考虑摩擦系数与相对磨损量，提出了综合摩擦系数作为配对摩擦副选材的依据；PCVD处理的铝合金材料与填充主材碳纤维PTFE的综合摩擦系数为6.1×10^-5，具有较低的综合摩擦系数、稳定的摩擦系数时序曲线和良好的表面形貌特征，可作为气缸-活塞环的配对摩擦副的优选方案之一。     

PTFE三层复合材料摩擦过程的界面动态迁移

在面接触摩擦磨损试验机上考察了PTFE三层复合材料的摩擦磨损性能,观察了其摩擦过程转移膜形成的动态过程,分析了其摩擦磨损机制。结果表明:PTFE三层复合材料在与对偶钢件摩擦时,会在摩擦界面上发生界面迁移,导致在对偶件表面形成一层转移膜。界面迁移的动态过程是:转移膜的形成开始是由于微切削机制使得PTFE复合材料镶嵌于对偶件表面的凹坑和微沟槽处,进而在机械和摩擦化学的作用下得以生长变大,最后形成较完整的转移膜。转移膜在形成与长大过程中,始终伴随着局部脱落以及再修复的过程,在形成较完整的转移膜后处于动态平衡。摩擦过程中转移膜的形成可以有效地稳定摩擦因数,减小磨损。     

汽车制动器摩擦副材料选择性配对问题的研究

汽车制动器摩擦副材料的配对一直是被忽视的一个问题。本文对汽车制动器广泛使用的对偶材质和新研制的四种对偶材质分别与石棉、粉末冶金和半金属摩擦片配对进行了试验研究,证实对偶材质不仅影响它本身的摩擦磨损性能,而且显著地影响摩擦片的摩擦磨损性能,理想的对偶能提高双方的耐磨性和增大摩擦系数,同时改善热衰退性能,使摩擦特性更加稳定。摩擦片对其对偶具有选择性配对的特性,对三种摩擦片的对偶研制出较好的配对材料。     

聚酰亚胺复合材料与不同金属间干滑动时的摩擦学性能

采用MPX-2000型摩擦磨损试验机研究了聚四氟乙烯和二硫化钼填充聚酰亚胺复合材料在干滑动摩擦条件下与45钢、镍铬合金、铜和铝对磨时的摩擦磨损性能,并利用扫描电子显微镜和光学显微镜分析了复合材料及对偶件的磨损表面形貌。结果表明:复合材料与铝对磨时的摩擦因数和磨损率最低,分别约为与钢摩擦时的43%和49%;摩擦后铝表面形成均匀连续的转移膜,45钢、镍铬合金和铜的表面没有形成有效转移膜,因此复合材料的摩擦因数较大;复合材料与不同金属材料摩擦时的磨损机理主要是粘着磨损与疲劳磨损。     

炭黑及丙烯腈含量对丁腈橡胶磨损机理的影响

丁腈橡胶是一种重要的螺杆泵定子材料.以不同炭黑及丙烯腈含量的丁腈橡胶与45#钢组成的摩擦副为研究对象,采用MPV-600型环-块摩擦磨损试验机,在干摩擦和原油润滑条件下进行摩擦磨损试验,对丁腈橡胶磨损量及摩擦系数进行分析,初步探讨了其磨损机理.从试验结果可以看出,干摩擦条件下丁腈橡胶的磨损量随着载荷的增大而增大,炭黑和丙烯腈含量的增加使丁腈橡胶的耐磨性增强.原油介质下的磨损规律与干摩擦基本相同,丁腈橡胶磨损表面平整,磨损量很小,且原油介质的润滑和冷却作用使橡胶的摩擦系数降低.     

表面氮化对活塞环摩擦磨损参数的影响分析

用摩擦磨损试验机对铸铁活塞环在氮化前后与高硼铜铸铁缸套配合分别进行了半小时和一小时摩擦磨损试验,测量了氮化前后的活塞环表面摩擦系数和磨损量、磨损率,并对磨痕进行了分析。结果表明:未氮化活塞环摩擦系数大于氮化环,摩擦系数变化稳定性比氮化活塞环差,未氮化环磨损量较氮化环增大了约39.6%(半小时)及51.0%(一小时),未氮化环磨损率的一小时试验比半小时试验平均升高6.7%,氮化环磨损率降低了13.7%,与未氮化环配合的缸套磨损量较与氮化环配合的缸套的磨损量和磨损率与活塞环比较规律一致,表面磨痕显示未氮化环磨损剧烈,由此氮化处理提高活塞环-缸套摩擦副的稳定性,且耐磨性得到提高。     

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。     

弹性体摩擦磨损特性的测试

本文对聚氨酯(PU)、聚氯乙烯(PVC)和一种橡塑复合材料的摩擦系数、相对磨损率进行了测试.在与钢配副的滑动摩擦情形下,用平面定力法测试摩擦系数时,采用位移定量法可以获得稳定的测试结果用环块摩擦副测试弹性体耐磨性时,对磨环的表面特性是影响测试结果的关键因素,使用砂轮对磨环所得测试结果稳定.     

改性硅线石填充双马来酰亚胺的摩擦学性能研究

研究了不同用量的偶联剂对硅线石表现改性的效果,测试了改性后马来酰亚胺复合材料的力学性能和不同载荷下的摩擦学性能,结果表明：乙烯基三乙氧基硅烷可用作硅线石和双马来酰亚胺复合体系的偶联剂,这种偶联剂使复合材料的抗冲击强度明显提高,硬度降低,耐磨性有较在原提高而磨擦系数略有降低。     

Wear mechanism of disc-brake block material for new type of drilling rig

To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Feabundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Feabundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.     

浸渍石墨/38CrMoAlA (喷涂)配对密封摩擦副的干摩擦性能

针对干摩擦机械密封在高速运转工况下密封端面的摩擦磨损而导致密封失效问题,通过试验分析几种典型摩擦副材料组对在干摩擦下的摩擦磨损性能。选择浸锑石墨M106D和浸树脂石墨M106K分别与38CrMoAlA以及喷涂Cr2O3、Al2O3的38CrMoAlA硬环组对,采用Plint摩擦磨损试验机,监测摩擦副在高速干摩擦条件下的摩擦因数,分析轴向载荷及线速度对摩擦因数的影响,通过白光干涉仪观测试验前后端面形貌。结果表明：干摩擦下,喷涂的硬环表面石墨转移附着较少,其更耐磨、磨损程度小,浸锑石墨较浸树脂石墨磨损少;6组配对试验主要磨损形式为磨粒磨损,其中浸锑石墨/喷涂Al2O3的38CrMoAlA摩擦副摩擦因数最小;由于石墨的自润滑性,适当增加转速和轴向载荷均有利于降低端面摩擦因数。     

Adhesive wear and frictional characteristics of UHMWPE and HDPE sliding against different counterfaces under dry contact condition

Abstract

The current work evaluates the wear and frictional performance of ultrahigh molecular weight polyethylene (UHMWPE) and high density polyethylene (HDPE) sliding against different metal counterfaces, stainless steel(SS), mild steel (MS) and aluminium (Al), under dry contact condition. The experiments were conducted using pin on disc machine at different sliding distances (0–40·32 km), 15 N applied load and 2·8 m s^–1 sliding velocity. Interface temperatures and frictional forces were measured simultaneously during the sliding, while specific wear rates were determined for every 1·68 km sliding distance. Based on the optical microscopy of the worn surface and wear track, frictional and wear results were analysed and discussed. The experimental results showed that the type of counterface material significantly influences both frictional and wear performances of the selected polymers. This was mainly due to the film transfer characteristics. Higher temperature and friction coefficient for UHMWPE and HDPE were evident when sliding took place against Al counterface. Sliding the polymers against stainless steel showed low friction coefficients compared to other counterfaces.     

Wear mechanism of disc-brake block material for new type of drilling rig

To improve friction and wear performance and service life of the disc-brake pair material of a drilling rig, a new type of asbestos-free frictional material with better performance for disc-brake blocks is developed, and its wear mechanism is investigated by friction and wear experiments. Topography and elementary components of the brake block’s wear surface are analyzed by employing SEM and EDAX patterns, revealing its tribological behaviour and wear mechanism. When the frictional temperature is lower, the surface film of the brake block is thinner, dense, smooth with plasticity, and divided into the mixture area, Fe-abundant area, carbon-abundant area and spalling area. The mixture area consists of various constituents of frictional pairs without ploughing and rolling trace. The Fe-abundant area mainly consists of iron and other constituents. The carbon-abundant area is the zone where graphite and organic fibre are comparatively gathered, while the spalling area is the zone where the surface film is spalled and its surface is rough and uneven, with a loose and denuded state. During the period of high frictional temperature, the frictional surface is also divided into the mixture area, Fe-abundant area and spalling area. In this case, the mixture area consists of abrasive dust from friction pairs, and the surface film is distributed with crumby hard granules, exiguous oxide, carbide granules and sheared slender fibre. The Fe-abundant area is mostly an oxide layer of iron with a flaky distribution. Fracture and spalling traces as well as an overlapping structure of multilayer surface films can be easily found on the surface film. The components of the spalling area are basically the same as that of the matrix. At the beginning of wear, the hard peaks from the friction surface of the disc-brake plough on the surface of the brake block. With increasing frictional temperature, the friction surface begins to soften and expand, and oxidized wear occurs at the same time. During the high-temperature wear period, severely influenced by friction heat, obvious softening and plastic flow can be found on the friction surface of the brake block, its anti-shearing ability is weakened, and adhesive wear is intensified. Thermal decomposition of cohesive material in the brake block is simultaneously strengthened, so that constituents shed due to loss of adhesion. Organic fibre is in a flowing state and obviously generates drawing, shearing, carbonization and oxidization. In addition, thermal cracking, thermal oxidization, carbonization and cyclization of organic substances on the surface of brake block can make the friction surface produce pores or cracks, thus fatigue wear occurs.     

微织构对硬质合金表面摩擦性能的影响

微织构是一种有效地改进表面摩擦性能和提高表面承载能力的措施.为了研究微织构在刀具减磨技术方面的应用,本文在WC-Co硬质合金材料表面制作出微坑阵列,与Ti6Al4V构成摩擦副,在微量润滑(MQL)条件下进行摩擦磨损试验.研究发现:红MQL条件下,微织构对WC-Co/Ti6Al4V摩擦副具有一定的减磨效果,低速高载和高速...     

The role of alloying elements in the friction and wear of copper alloys

The effect of Sn and Al on the wear and frictional properties of Cu-Sn and Cu-Al alloy systems was investigated by electron probe microanalysis and Auger electron spectroscopy. The coefficient of friction and the wear loss in the Cu-Sn alloy increased with increasing Sn content and reached a maximum at about 40% Sn, which corresponds to ?-Cu₃Sn. With the Cu-Al alloy system the coefficient of friction initially decreased with increasing Al content and reached a minimum at about 20% Al corresponding to the composition Cu₉Al₄. The wear loss increased initially, reached a maximum at about the solubility limit of Al and then decreased rapidly.The coefficient of friction of a Cu-Sn solid solution showed a maximum at the initial stage in the friction coefficient-sliding time curve, which was not found with Cu-Al and Cu-Zn. This phenomenon is discussed on the basis of surface compositional changes during the friction process.     

等离子喷涂陶瓷涂层在高温（450℃）下的摩擦磨损机理分析

本文用SEM观察分析了等离子喷涂陶瓷涂层（Metco136F,Metco80NS,Metco102,Metco105,Metco202NS,国产Al 2O 3）在高温无油和有油润滑下的摩擦磨损机理。发现陶瓷涂层仍会象金属摩擦副那样出现疲劳脱落、塑性形变、粘着撕裂。450℃时的干摩擦系数比有油润滑的摩擦系数高得多,且磨损表面形貌和磨损机理与有油润滑时大为不同。干磨擦是较易出现粘着磨损,而有润滑时则较难出现。     

Fretting wear behavior of nitrogen ion implanted titanium alloys in bovine serum lubrication

Nitrogen ion implantation was performed on biomedical titanium alloys by using of the PBII technology to improve the surface mechanical properties for the application of artificial joints. The titanium nitride phase was characterized with X-ray photoelectron spectroscopy (XPS). The nanohardness of the titanium alloys and implanted samples were measured by using of in-situ nano-mechanical testing system (TriboIndenter). Then, the fretting wear of nitrogen ion implanted titanium alloys was done on the universal multifunctional tester (UMT) with ball-on-flat fretting style in bovine serum lubrication. The fretting wear mechanism was investigated with scanning electron microscopy (SEM) and 3D surface profiler. The XPS analysis results indicate that nitrogen diffuses into the titanium alloy and forms a hard TiN layer on the Ti6Al4V alloys. The nanohardness increases from 6.40 to 7.7 GPa at the normal load of 2 mN, which reveals that nitrogen ion implantation is an effective way to enhance the surface hardness of Ti6Al4V. The coefficients of friction for Ti6Al4V alloy in bovine serum are obviously lower than that in dry friction, but the coefficients of friction for nitrogen ion implanted Ti6Al4V alloy in bovine serum are higher than that in dry friction. Fatigue wear controls the fretting failure mechanism of nitrogen ion implanted Ti6Al4V alloy fretting in bovine serum. The testing results in this paper prove that nitrogen ion implantation can effectively increase the fretting wear resistance for Ti6Al4V alloy in dry friction, and has a considerable improvement for Ti6Al4V alloy in bovine serum lubrication.     

Al2O3-40%TiO2涂层/锡青铜的摩擦磨损性能研究

在室温下对Al2O3-40%TiO2涂层与锡青铜摩擦副进行了油润滑情况下的球盘式摩擦磨损试验。使用SEM分析了磨损表面形貌特性;同时采用EDAX进行了磨损微观区域的成分分析。结果表明:在FD-7主轴润滑油的条件下,A l2O3-40%TiO2涂层与锡青铜之间发生了明显的涂抹和擦伤现象,涂层摩擦磨损性能优异。