溅射沉积MoS_2/Sb_2O_3复合润滑膜的摩擦磨损过程与失效分析

采用UMT-2型球-盘摩擦磨损试验机研究溅射沉积MoS2/Sb2O3复合固体润滑膜的滑动摩擦磨损寿命,采用显微镜分析球-盘摩擦副在不同磨损阶段的磨损形貌与磨损状况,并对磨痕位置S、Mo元素进行XPS分析。结果表明:在摩擦磨损寿命试验过程中,摩擦副的接触方式最开始的点接触逐步过渡到面接触;MoS2固体润滑膜对滑动摩擦副的延寿作用是基底材料表面的有效厚度润滑膜及MoS2对摩擦偶件(钢球)的转移;机械磨损的剪切剥离效应是润滑失效的主要原因,MoS2的氧化在一定程度上加剧了润滑失效的进程。     

多功能摩擦磨损试验机系统设计

为研究自润滑关节轴承摩擦副材料在空间环境下的摩擦学性能,在已有空间环境模拟装置的基础上,设计了一种新型摩擦磨损试验机。采用模块化设计方法设计了试验机的型谱,对其进行了功能分析和模块划分,并组建了以摩擦副接触形式为特征的功能变换矩阵。系统介绍了试验机的构成并对试验机进行了试验验证,试验结果表明:试验机能够进行多种接触形式的摩擦磨损试验,具有良好的可靠性,实现了一机多用。     

车辆齿轮油承载能力的估算

从纳米摩擦学角度考察了车辆齿轮的四球机测定结果,发现最大无卡咬负荷ＰＢ和烧结负荷ＰＤ值不能很好地代表承载能力。阐明了由这两个指标难于预测车辆齿轮油承载能力的原因是：（１）钢球材质与实际摩擦副的不同;（２）钢球的接触方式是点接触;而齿轮是线接触;首次提出一套利用四球机测试估算车辆齿轮油承载能力的方法,指出实际选择齿轮油时可根据经的啮合压力来确定油品在四球机试验中应达到的比压力。     

义齿材料摩擦磨损试验机及控制系统设计

根据义齿摩擦磨损试验环境标准开发设计了温度和湿度可控制的往复式摩擦磨损试验机.该试验机采用曲柄导杆滑块机构实现往复运动,使用球一盘接触方式进行试件摩擦磨损,利用半导体应变片对摩擦过程中摩擦系数进行动态跟踪测试,通过调整砝码实现正压力的改变,通过改变偏心轮的偏心距实现往复行程变化.该试验机不但可对义齿材料进行摩擦磨损试验,还可对金属及其他非金属材料进行摩擦磨损试验.     

某型产品转速传感器滚针摩擦副磨损浅析

对航空发动机燃油系统某型产品机械式转速传感器支承滚针摩擦副磨损进行了技术研究,通过支撑滚针摩擦副结构介绍、滚针摩擦比功(P_v值)与接触温升ΔT_(max)计算分析,得出接触温升与摩擦副接触球面球冠圆心角关系,将摩擦副支撑滚针球头与球窝接触表面球冠圆心角控制在小于50°,以提高摩擦副接触贴合度,使该摩擦副工作中处于最佳磨损状态,提高了摩擦副的可靠性,保证了产品满足翻修寿命(300 h)的磨损要求。     

基于虚拟仪器的滑动轴承摩擦试验系统的设计

通过改造MS-800A四球摩擦试验机的摩擦实验部分,引入虚拟仪器LabVIEW软件建立测试系统,对摩擦副之间摩擦系数和温度的变化进行采集、处理和实时检测,建立对滑动轴承的摩擦磨损试验系统,从而建立一套研究滑动轴承在不同工况条件（润滑介质、载荷和转速）下的摩擦磨损特性。     

空心微珠在基础油中的摩擦学性能研究

制备出双重改性空心微珠并作为润滑添加剂添加到500SN基础油中,通过光学显微镜观察,双重改性空心微珠在基础油中的分散性良好,具有完美的球形结构,其粒径约为1.83μm。考察含有不同质量分数空心微珠的500SN基础油在四球试验机和HQ-1试验机中的摩擦学性能。其中四球机为点接触方式,HQ-1为线接触方式。结果表明当空心微珠添加质量分数为0.5%时,四球试验机的pB值升高8.51%,且有效地降低了摩擦磨损,在HQ-1试验机中也取得良好的抗磨减摩性能。通过SEM、EDS、XPS观察分析线接触试验的试块磨痕,提出空心微珠在基础油中具有抛光、沉积和滚滑作用。     

点/线/面接触条件下喹唑啉酮胺润滑油添加剂的摩擦学性能

目前杂环化合物作为润滑油添加剂在机械润滑领域受到重视,但对无硫磷含氮杂环化合物在多种接触方式下的摩擦学性能的研究还不多。合成一种新型无硫磷喹唑啉酮胺润滑油添加剂并利用四球试验机、环块试验机和万能摩擦磨损试验机分别考察了点/线/面接触条件下其在液体石蜡中的摩擦学性能,再用光学显微镜、扫描电子显微镜和X射线光电子能谱仪对其摩擦表面进行分析。试验结果表明:油溶性喹唑啉酮胺在液体石蜡中能显著改善基础油的摩擦磨损状况,明显提高基础油的承载能力,表现出良好的摩擦学性能,其作用机理是其在摩擦过程中与金属表面发生了摩擦化学反应,生成了含氧化亚铁、有机氮化物和含氮金属配合物等的复合膜,有效地提高了液体石蜡的减摩抗磨性能。     

一种多功能摩擦磨损试验机

对现有的一台直线往复式摩擦磨损试验机的传动系统、润滑系统等进行改造,使其成为一台旋转式摩擦磨损试验机。新试验机不仅能模拟不同材料、不同表面结构的环—块、环—环等旋转摩擦磨损过程,还能进行不同接触形式以及润滑状态下的旋转摩擦磨损试验研究。经线接触摩擦磨损试验验证,改造后的试验机能够满足设计要求。     

几种超细粒子在半流体脂中的摩擦行为

对一些软金属粉和常用的固体润滑剂石墨粉以及气相SiO2在半流体脂中的分散稳定性和摩擦行为进行了考察。摩擦试验研究了它们的抗磨性（四球机长期磨损）、承载能力（PB值）、摩擦系数，同时通过台架试验，发现它们均具有良好的润滑特性和分散稳定性。     

抗磨型油膜轴承油极压抗磨性能的研究

用油膜承载能力及四球机试验等方法极压抗磨性能，以硫磷型极压抗磨剂和油性剂等为主剂进行复配，对油品配方研究及解决极压抗磨性能打下了基础，。产品轻工业现场使用试验证明，极压抗磨性能完全能够满足设备的使用要求。     

Influence of a low temperature sulphurizing process on lubricants in standard ep and fzg tests

The influence of the Sulf BT process, an anodic sulphurizing process, on the performance of a non-EP turbine oil and an EP gear oil has been tested. Both standard EP (four-ball, Timken and Falex) and gear-simulating (FZG) tests, were used on plain and sulphurized specimens. EP tests showed increased performance for the sulphurized specimens: the most remarkable result was noted in the four-ball and Timken tests, where the turbine oil attained a performance typical of commercial EP lubricants. FZG tests, however, showed no improvement, the sulphide film being progressively worn away during the tests and thereby having no influence on the results. The disagreement between EP and FZG determinations points to the fact that predictions from measurements of load-carrying capacity on the commonly used laboratory devices may not agree at all with behaviour on machines more closely simulating actual service.     

Influence of a low temperature sulphurizing process on lubricants in standard ep and fzg tests

The influence of the Sulf BT process, an anodic sulphurizing process, on the performance of a non-EP turbine oil and an EP gear oil has been tested. Both standard EP (four-ball, Timken and Falex) and gear-simulating (FZG) tests, were used on plain and sulphurized specimens. EP tests showed increased performance for the sulphurized specimens: the most remarkable result was noted in the four-ball and Timken tests, where the turbine oil attained a performance typical of commercial EP lubricants. FZG tests, however, showed no improvement, the sulphide film being progressively worn away during the tests and thereby having no influence on the results. The disagreement between EP and FZG determinations points to the fact that predictions from measurements of load-carrying capacity on the commonly used laboratory devices may not agree at all with behaviour on machines more closely simulating actual service.     

Effect of Gear Surface and Lubricant Interaction on Mild Wear

In this study, a twin-disc test machine was used to simulate a rolling/sliding gear contact for three surface finishes, each run with two types of lubricants, thus seeking to develop insight into the tooth flank/lubricant tribological system. The test disc surfaces were case-carburised before the surfaces were produced by: transverse grinding followed by a mechanical abrasive polishing process; transverse grinding only; and transverse grinding followed by preheating as a final finishing step (intended to enhance the build-up of an easily sheared surface boundary layer using a sulphur additive). The twin-disc contact was lubricated with an ester-based environmentally adapted lubricant or a polyalphaolefin-based commercial heavy truck gearbox lubricant. To obtain information about the composition of chemically reacted surface layers, the specimens used were analysed using glow discharge-optical emission spectroscopy. The results indicate that the interactions between different surface finishes and lubricants have different impacts on friction behaviour, wear and the reacted surface boundary layer formed by the lubricant. Running a smooth (polished) surface with the appropriate lubricant drastically reduces the friction. Surface analysis of the ground surfaces gives clear differences in lubricant characteristics. The commercial lubricant does not seem to react chemically with the surface to the same extent as the EAL does. Micropitting was found on all ground discs with both lubricants, though at different rates. The highest amount of wear but less surface damage (i.e. micropits) was found on the preheated surface run with the commercial lubricant.     

Micropitting performance of nitrided steel gears lubricated with mineral and ester oils

This study compares the gear micropitting performance of high pressure nitriding (HPN) steel gears, lubricated with three different gear oils: a standard mineral lubricant, containing a special micropitting additive package, and two biodegradable esters with low toxicity additivation. The physical, chemical and wear properties of the three lubricants were determined, as well as their biodegradability and toxicity characteristics. The gear material and the corresponding heat treatment are presented.Gear simulation tests were performed in a Falex machine, using a roller-disc geometry, in order to evaluate the lubricant temperature and friction coefficient corresponding to each gear oil.Gear micropitting tests were performed on the FZG machine, using type C gears, and lubricant samples were collected during the tests for wear particle analysis. Post-test analysis included the mass loss measurement of the gear (pinion and wheel), the ferrometric analysis of the lubricant samples and the teeth flank roughness measurement below and above the pitch line. The teeth flanks were inspected using scanning electron microscopy (SEM) and surface topography measurements to assess the number and depth of micropits. Metallurgical cuts were done to observe the size and depth of micropits as well as contact fatigue crack initiation and propagation.The ester lubricants show better micropitting performance than the mineral oil, confirming the potential of environmental friendly fluids as high-performance gear oils.     

Friction of Undulated Surfaces Coated with MoS2 by Pulsed Laser Deposition

Solid lubricants such as molybdenum disulfide can provide very low friction, but their effectiveness especially in the geometrically constrained sliding pairs is limited by plowing of coated surfaces by wear particles. Even in the presence of solid lubricants wear particles cause higher friction by plowing the interface. To minimize plowing, undulated surfaces with microgrooves perpendicular to the sliding direction can be used to trap wear particles. Smooth and undulated stainless steel surfaces were coated with molybdenum disulfide by pulsed laser deposition (PLD) and friction tested. Under identical test conditions, the friction coefficient of coated undulated surfaces is between 20–40 percent lower than that of coated smooth surfaces. The friction coefficient of undulated uncoated surfaces is about 100–350 percent less than that of smooth uncoated surfaces. Moreover, the entrapment of wear particles at the interfaces of geometrically constrained bearings may lead to seizure even when bearing surfaces are coated with solid lubricants. The use of undulated surf aces on these sliding systems has shown improved operating time and a reduced maintenance cycle.     

不同摩擦副中Si3N4陶瓷摩擦磨损特性研究

奥氏体不锈钢1Cr18Ni9Ti是难切削材料之一。本研究采用一种销盘试验机,模似陶瓷刀具实际切削加工时使用状况,考察了Si_3N_4/不锈钢摩擦副的摩擦学性能,并着重考察了与不锈钢对磨时Si_3N_4陶瓷的磨损特性。作为比较,对Si_3N_4/45号钢摩擦副的摩擦磨损性能也进行了较为详细的考察。试验结果表明,相同试验条件下,Si_3N_4/不锈钢中Si_3N_4,陶瓷的磨损率比Si_3N_4/45~#钢摩擦副中Si_3N_4的磨损率约大2个数量级。润滑剂对两种摩擦副摩擦磨损性能的影响也有很大差别。借助扫描电镜,X光电子能谱,俄歇电子能谱等多种分析手段对Si_3N_4陶瓷的磨损机理进行了分析,并对两种摩擦副中Si_3N_4磨损率的差别作了讨论。     

A Tribological Study of Multiply-Alkylated Cyclopentanes and Perfluoropolyether Lubricants for Application to Si-MEMS Devices

Lubrication of Micro-Electro-Mechanical Systems (MEMS) is a major constraint in MEMS applications, restricting the designs and practical usages of such devices. Possible lubricants and methods have been investigated in this paper, comparing perfluoropolyether (PFPE) lubricant with multiply-alkylated cyclopentanes (MACs). The effectiveness of both the lubricants in reducing friction and enhancing the wear life was investigated in a new method of MEMS lubrication known as Localised-Lubrication or “Loc-Lub.” Friction and wear tests were conducted in a flat-on-flat test geometry under a normal load of 50 g and a sliding velocity of 5 mm s^?1 in reciprocation, with Si as the substrate. Further tests were conducted at higher loads, to compare wear durability between lubricants and methods. It was found that MACs have a propensity to remain cohesive during the tests due to higher surface tension and provide better friction and wear properties when tested under reciprocating sliding conditions, as a complete film is present between the two surfaces. The results show that MAC lubricant is more effective in extending the wear life and reducing friction under the tested conditions compared to PFPE.     

The significance of load and rubbing time in the fourball lubricant test

Four-ball tests were run on compounded oils made up with the following additives: (a) di-t-octyl disulfide; (b) t-octyl chloride; (c) a dualcomponent disulfide-chloride mixture. Two test procedures were used for most of the work: 10 s runs with load as the variable experimental parameter and runs in which the load was held constant and the rubbing time was varied. Some runs were also made with a varied load for 2 s of running time. The wear scar dimensions were converted to wear volumes. None of the lubricants exhibited constant-rate load-governed wear behavior. The behavior of lubricants compounded with di-t-octyl disulfide or with t-octyl chloride was characterized by distinct load-governed transitions to increased wear; the dual-component additive did not show any sharp transitions but did depart from linear load-governed wear behavior. Transitions to increased wear at a load which was subtransitional for 10 s of rubbing could be induced by prolonging the time of rubbing. Suggestive parallelisms were observed in the effects of load and rubbing time as the experimental parameter. The role of load and rubbing time in the operation of the four-ball machine is examined and an approach to the rationale of evaluating lubricants by the four-ball test is suggested.     

Friction coefficient in FZG gears lubricated with industrial gear oils: Biodegradable ester vs. mineral oil

Two industrial gear oils, a reference paraffinic mineral oil with a special additive package for extra protection against micropitting and a biodegradable non-toxic ester, were characterized in terms of their physical properties, wear properties and chemical contents and compared in terms of their power dissipation in gear applications [Höhn BR, Michaelis K, Döbereiner R. Load carrying capacity properties of fast biodegradable gear lubricants. J STLE Lubr Eng 1999; Höhn BR, Michaelis K, Doleschel A. Frictional behavior of synthetic gear lubricants. Tribology research: from model experiment to industrial problem. Elsevier 2001; Martins R, Seabra J, Seyfert Ch, Luther R, Igartua A, Brito A. Power Loss in FZG gears lubricated with industrial gear oils: biodegradable ester vs. mineral oil. Proceedings of the 31th Leeds-Lyon symposium on tribology. Elsevier; to be published; Weck M, Hurasky-Schonwerth O, Bugiel Ch. Service behaviour of PVD-coated gearing lubricated with biodegradable synthetic ester oils. VDI-Berichte Nr.1665 2002.]. The viscosity–temperature behaviors are compared to describe the feasible operating temperature range.Standard tests with the Four-Ball machine and the FZG test rig [Winter H, Michaelis K. FZG gear test rig—desciption and possibilities. In: Coordinate European Council second international symposium on the performance evaluation of automotive fuels and lubricants; 1985.] characterize the wear protection properties. Biodegradability and toxicity tests are performed in order to assess the biodegradability and toxicity of the two lubricants.Power loss gear tests are performed on the FZG test rig using type C gears, for wide ranges of the applied torque and input speed, in order to compare the energetic performance of the two industrial gear oils. Lubricant samples are collected during and at the end of the gear tests [Hunt TM. Handbook of wear debris analysis and particle detection in liquids. UK: Elsevier Science; 1993.] and are analyzed by Direct Reading Ferrography (DR3) in order to evaluate and compare the wear particles concentration indexes of both lubricants.An energetic model of the FZG test gearbox is developed, integrating the mechanisms of power dissipation and heat evacuation, in order to determine its operating equilibrium temperature. An optimization routine allows the evaluation of the friction coefficient between the gear teeth for each lubricant tested, correlating experimental and model results.For each lubricant and for the operating conditions considered, a correction expression is presented in order to adjust the friction coefficient proposed by Höhn et al. [Höhn BR, Michaelis K, Vollmer T. Thermal rating of gear drives: balance between power loss and heat dissipation. AGMA Technical Paper; October 1996. pp 12. ISBN: 1-55589-675-8.] to the friction coefficient exhibited by these lubricants. The influence of each lubricant on the friction coefficient between the gear teeth is discussed taking into consideration the operating torque and speed and the stabilized operating temperature.