载流下MoS2/Ag纳米复合薄膜摩擦学性能

MoS₂基纳米复合薄膜具有良好的摩擦学性能,但较差的导电性能限制了其在载流条件下作为润滑材料的应用。为提高MoS₂基纳米复合薄膜的导电性能,采用非平衡磁控溅射系统沉积2种不同Ag含量的MoS₂/Ag纳米复合薄膜,并在不同的电流条件下研究MoS₂/Ag纳米复合薄膜与GCr15钢球对摩时的摩擦学性能。结果表明：在载流下2种MoS₂/Ag纳米复合薄膜表现出相似的摩擦性能,而低掺杂MoS₂/Ag薄膜具有更佳的耐磨性能,这归因于低掺杂MoS₂/Ag薄膜具有较好的力学性能;无载流时,MoS₂/Ag纳米复合薄膜在摩擦过程中生成的氧化物颗粒增加了磨损、降低了润滑性,磨损机制主要为磨粒磨损;电流小于0.5 A时,电流促进了转移膜形成,使得摩擦因数降低,但磨损率增加,磨损机制主要为黏着磨损;当电流大于0.5 A时,由于电弧烧蚀加速了薄膜的磨损,磨损机制主要为磨粒磨损、黏着磨损和电弧腐蚀磨损。     

MoS2／Zr复合涂层高速钢刀具的切削性能研究

采用中频磁控溅射和多弧离子镀相结合的工艺在M2高速钢麻花钻表面沉积制备了MoS2/Zr复合涂层,考察了复合涂层的表面形貌及力学性能,在干式切削条件下研究了复合涂层刀具钻削45钢的切削性能.结果表明,与纯MoS2 涂层相比,MoS2/Zr 复合涂层的硬度显著提高,与无涂层高速钢刀具相比,MoS2/Zr复合涂层刀具的切削能力提高了约4倍.复合涂层的存在使得刀具主切削刃的后刀面磨损量明显减小,刀具的黏结磨损和磨粒磨损程度显著降低.MoS2/Zr复合涂层刀具后刀面和横刃的磨损形式主要为涂层的分层剥落,同时伴随有一定程度的黏结磨损和磨粒磨损.     

阀门零件表面二硫化钼涂覆工艺的研究

介绍了表面技术的分类及特点,阐述了阀门零部件二硫化钼涂覆技术的应用工艺。     

二硫化钼振动涂敷系统研制

二硫化钼（MoS2）振动涂敷技术通过将四度空间振动台、蜂窝状振动盒、鼓风机、抽风机、控制装置和执行装置等组合运用,实现了振动与分离功能,采用特殊的 MoS2造粒料并设计合理的操作工艺,实现了小型金属零件 MoS2振动涂敷经实际生产验证可替代人口涂敷,零件经涂敷后具有表面光滑、无浮粉、环保芯特点。     

关节轴承喷涂MoS_2/石墨复合涂层摩擦学性能的研究

以Mo S2/石墨为固体润滑剂,无机磷酸盐为胶粘剂,利用喷涂方式在GE20ES型关节轴承表面制备不同配比的Mo S2/石墨复合涂层,考察了这些复合涂层在旋转摆动条件下的摩擦磨损性能。结果表明,不同配方的Mo S2/石墨复合涂层均显示了较好的减摩耐磨性能,其中当Mo S2与石墨的配比为3∶1时,Mo S2与石墨有较好的协同效果,复合涂层的摩擦学性能最好。     

石墨烯/MoS2复合涂层多环境下的摩擦学性能

以MoS2作为润滑剂,以石墨烯(GE)作为润滑添加剂,采用喷涂法在GCr15钢样片表面制备不同含量的GE/MoS2复合涂层.利用HSR-2M型高速往复式摩擦磨损试验机测试涂层在干摩擦及海水环境中的摩擦磨损性能,并分析了磨痕形貌及磨损机制.结果表明:添加适量石墨烯可明显改善MoS2涂层的摩擦磨损性能,且海水环境中涂层的摩...     

Role of MoS2 morphology on wear and friction under spectrum loading conditions

One of the ways by which grease is evaluated is by using a four‐ball wear test using ASTM D2266. However, actual applications may require bearings to be subjected to spectrum loading conditions. This study focuses on using ball milling to mitigate the wear from sharp edges in the MoS₂ particles. Two different blends of greases were formulated using MoS₂ in the as‐received state (unmilled) and milled MoS₂; they were tested under spectrum loading conditions where the load and frequency of the tests were treated as variables. It was found that ball milling of the MoS₂ significantly reduces the wear under spectrum loading condition both for ramp‐up and ramp‐down conditions. It was also shown that shortening the time step for both the ramp‐up and ramp‐down cycles resulted in larger wear for unmilled MoS₂ particles in comparison with milled MoS₂ particles in grease. The milling process did not play a significant role when frequency of the test was either ramped up or down. Copyright © 2015 John Wiley & Sons, Ltd.     

Friction and wear processes in piston rings

It has been recognised that a large part of the top piston ring wear of an ic engine takes place in boundary lubrication around top dead centre (tdc) position. A quantitative assessment of the friction behaviour using actual piston ring and cylinder liner under conditions close to tdc has been made. The factors responsible for wear under these conditions have been identified as surface temperature, peak combustion pressure, total energy on the wearing surfaces and other physical properties of the material under sliding     

Sb2S3和MoS2的协同作用对摩擦材料摩擦性能的影响

采用MPX-2000型磨损试验机和定速摩擦实验机分别测试不同载荷及不同温度下固体润滑剂Sb2 S3和MOS2对摩擦材料摩擦性能的影响,探讨2种固体润滑剂的协同作用;采用扫描电镜分析摩擦材料磨损后摩擦表面的微观形貌.结果表明,固体润滑剂Sb2 S3和MoS2具有良好的协同效应,可大大改善摩擦材料的摩擦性能,这是因为MOS2和Sb2 S3分别在制动过程中的低温段和高温段起到良好的润滑作用.当Sb2S3的体积分数为6%,MoS2的体积分数为3%时,摩擦材料的摩擦性能最佳.     

Wear behavior and mechanisms of alumina-based ceramic tools in machining of ferrous and non-ferrous alloys

In this paper, the machining performance and wear mechanisms of two alumina-based ceramic cutting tools (Al₂O₃/TiB₂ and Al₂O₃/TiB₂/SiC_w) in continuous turning of hardened steel and nickel based alloy (Inconel 718) were examined. Results showed that in turning of hardened steel performed under identical conditions, Al₂O₃/TiB₂/SiC_w tool exhibited lower flank wear resistance than that of Al₂O₃/TiB₂ tool, the mechanisms responsible for this were determined to be the strong atom bonding between SiC and Fe, and the whisker pullout from the matrix for Al₂O₃/TiB₂/SiC_w ceramic tool. In continuous turning of Inconel 718, the Al₂O₃/TiB₂/SiC_w tool showed greatly improved flank wear resistance compared to Al₂O₃/TiB₂ tool, adhesion and abrasion wear were found to be the dominant wear mechanisms, the adhesion and diffusion of Ni, and Cr of Inconel 718 to the tool rake face may accelerate the tool wear rates.     

MoS2/石墨溅射涂层在真空中不同载荷下的摩擦磨损行为研究

为改进纯MoS2涂层的耐磨损性能,采用溅射技术合成了添加石墨的MoS2涂层。在球-盘摩擦试验机上,考察了法向载荷对MoS2/石墨溅射涂层真空中的摩擦因数和磨损率的影响,并利用扫描电子显微镜对其磨损形貌进行了分析。结果表明:在真空条件下,涂层的摩擦因数随着法向载荷的增大而减小;磨损率随载荷的增加而增加。涂层在真空中较低载荷下的磨损机制为疲劳磨损;在较高载荷下的磨损主要由塑性变形引起的小板片磨损控制。     

Friction and dry sliding wear behavior of carbon and glass fabric reinforced vinyl ester composites

Friction and dry sliding wear behavior of glass and carbon fabric reinforced vinyl ester composites have been presented. The results show that the coefficient of friction and wear rate increased with increase in load/sliding velocity and depends on type of fabric reinforcement and temperature at the interphase. The excellent tribological characteristics were obtained with carbon fiber in vinyl ester. It is believed that a thin film formed on counterface was seems to be effective in improving the tribological characteristics. The worn surfaces examined through SEM, showed higher levels of broken glass fiber in vinyl ester compared to carbon-vinyl ester composites.     

MoS2的表面修饰与摩擦学性能研究

分别用油酸（OA）、司班-60（Span-60）、十六烷基三甲基溴化铵（CTAB）-二烷基二硫代磷酸吡啶盐（Py-DDP）对MoS2纳米微粒进行表面修饰,考察了修饰后微粒的形貌、在液体石蜡中的分散稳定性和润滑性能,并采用四球摩擦磨损机测试了其摩擦学性能。结果表明,选用不同修饰剂所得到的修饰MoS2纳米微粒的稳定性和摩擦学性能均有不同程度的提高,其中以CTAB—PyDDP修饰MoS2纳米微粒的分散稳定性更佳,摩擦学性能最好。     

Mo/MoS2-Pb-PbS复合薄膜的真空摩擦学行为研究

多组元复合是提高润滑薄膜苛刻工况下服役性能的有效方法。采用“射频磁控溅射+低温离子渗硫”复合工艺,在9Cr18轴承钢表面制备了Mo/MoS2-Pb-PbS复合固体润滑薄膜;利用自主研制的MSTS-1型多功能真空摩擦磨损试验机研究了8×10-5 Pa真空条件下法向载荷和滑动速率对Mo/MoS2-Pb-PbS复合薄膜摩擦学性能的影响。结果表明,在所设定的5种滑动速率下,Mo/MoS2-Pb-PbS薄膜的摩擦因数随滑动速率的增大而缓慢减小,磨损率经一定周次的跑合后逐渐趋于稳定;在不同的法向载荷下,随着载荷的增大,薄膜的摩擦因数呈近似抛物线增大,变化范围在0.03～0.24之间;薄膜表面的磨痕宽度同样随着载荷的增大而增大。     

Simulation of the tribological behaviour of components and cutting tools by means of model wear testing

Modelling the wear test process can initiate real-life friction and wear of components and cutting tools. In this paper we describe model wear tests that were developed to discover (a) whether or not simulation of the wear processes that occur during cutting is possible, and (b) how the wear of indexable inserts can be reduced by using thin hard coatings, e.g. TiN, (Ti,Al)N, Ti(C,N) when milling metallic materials. The real-life wear of the track groups of various tracked vehicles was also investigated, in order to evaluate the wear resistance of certain materials.     

Friction and wear of blended polyoxymethylene sliding against coated steel plates

Measurements were made of the dynamic friction coefficients and specific wear rates of several thermoplastics rubbing against relatively soft coatings on steel plates. Polyoxymethylene (POM)-based composites were investigated using reciprocating, line contact tests against two types of corrosion-protected steel plates (electro-deposited cathodic epoxy layers, called “E-coatings”, and galvanised plates). In addition to virgin POM, composites containing glass fibres, polytetrafluoroethylene (PTFE) fibres, PTFE micro-powder, and high-viscosity silicon oil were investigated. Sliding speeds ranged from 0.05 to 0.3 m/s, and normal loads ranged from 5 to 30 N. The E-coating failed at high loads and velocities. The beneficial effects of lubricating additives in tests with uncoated steel counterfaces were also observed with the coated steel surfaces. POM with glass fibre additives was found to be more abrasive than the base material. The considered non-conformal contact produced similar friction and wear trends than those obtained for the conformal contact.     

Friction and wear behaviour of plasma-sprayed Cr2O3 coatings against steel in a wide range of sliding velocities and normal loads

This study investigates the influence of sliding speed and normal load on the friction and wear of plasma-sprayed Cr₂O₃ coatings, in dry and lubricated sliding against AISI D2 steel. Friction and wear tests were performed in a wide speed range of 0.125–8 m/s under different normal loads using a block-on-ring tribometer. SEM, EDS and XPS were employed to identify the mechanical and chemical changes on the worn surfaces. A tangential impact wear model was proposed to explain the steep rising of wear from the minimum wear to the maximum wear. The results show that the wear of Cr₂O₃ coatings increases with increasing load. Secondly, there exist a minimum-wear sliding speed (0.5 m/s) and a maximum-wear sliding speed (3 m/s) for a Cr₂O₃ coating in dry sliding. With the increase of speed, the wear of a Cr₂O₃ coating decreases in the range 0.125–0.5 m/s, then rises steeply from 0.5 m/s to 3 m/s, followed by a decrease thereafter. The large variation of wear with respect to speed can be explained by stick-slip at low speeds, the tangential impact effect at median speeds and the softening effect of flash temperature at high speeds. Thirdly, the chemical compositions of the transfer film are a-Fe₂O₃ in the speed range 0.25–2 m/s, and FeO at 7 m/s. In addition, the wear mechanisms of a Cr₂O₃ coating in dry sliding versus AISI D2 steel are adhesion at low speeds, brittle fracture at median speeds and a mixture of abrasion and brittle fracture at high speeds. Finally the lubricated wear of Cr₂O₃ coating increases sharply from 1 to 2.8 m/s.     

Investigation on MoS2 and graphite coatings and their effects on the tribological properties of the radial spherical plain bearings

With constant enlargement of the application areas of the spherical plain bearings, higher quality lubrication of the bearings is required. To solve the lubricating problems of spherical plain bearings under high temperature, high vacuum, high speed, heavy loads and strong oxidation conditions, it is urgent for us to develop more excellent self-lubricating technologies. In this paper, the bonded solid lubricant coatings, which use inorganic phosphate as the binder, the mixture of MoS2 and graphite with two different weight proportions as the solid lubricant, are prepared by spraying under three different spray gun pressures. The bonding strength tests on the coatings show that the best spraying pressure is 0.2 MPa and the better mixing proportion of MoS2 to Graphite is 3:1. Then for the radial spherical plain bearings with steel/steel friction pair, after the coatings are made on the inner ring outer surfaces, the friction coefficient, the wear loss and the friction temperature of the bearings under four oscillating frequencies are investigated by a self-made tribo-tester. The test results, SEM of the worn morphologies and EDS of worn areas show that tribological properties of the bearing are obviously improved by the bonded solid lubricant coatings. When sprayed under the spray gun pressure of 0.2 MPa, the bearings have better anti-friction and anti-wear properties than those sprayed under 0.1 MPa and 0.3 MPa. Further as proved from the XPS analysis, between the coating with 3:1 mixing ratio of MoS2 to Graphite and the coating with 1:1 ratio, the former has less oxidation occurred on the surface and therefore has better tribological characteristics than the latter. This paper provides a reference to developing a new product of the radial spherical plain bearings with high bonding strength, oxidation resistance and abrasion resistance.     

添加纳米MoS2镍-磷化学复合镀层的制备与微观形貌

运用化学复合镀技术制备出添加纳米MoS2的镍-磷复合镀层.研究了制备过程中镀液中分散剂种类、MoS2添加数量以及镀前试样表面粗糙度对复合镀层的影响.结果表明:十六烷基三甲基溴化铵(CTAB)可以很好地在镀液中分散纳米MoS2,镀液中添加纳米MoS2颗粒的最佳值是2.0 g/L;镀前试样表面粗糙度值过低不利于提高复合镀层中纳米MoS2的复合量.     

Thermal wear and electrical sliding wear behaviors of the polyimide modified polymer-matrix pantograph contact strip

In the present study, the polyimide resin (PI)/cashew-modified resin (YM) polymer-matrix pantograph contact strip (PMPCS) was prepared by using hot repressing, hydro-solidification and dipping treatment processes. The thermal properties of cured resins were studied by thermogravimetry analyzer and differential scanning calorimetry. The thermal wear and electrical sliding wear behaviors of PMPCS against copper were evaluated by a ring block wear tester at elevated temperature under dry sliding conditions and a wear tester which simulated the train motion under laboratory conditions, respectively. Worn surfaces and wear debris of PMPCS were analyzed by scanning electron microscopy and energy dispersive spectrometer, and the wear mechanism was discussed. It has been found that the thermal stability of the PI/YM is superior to that of the YM under the same testing conditions. The results also showed that PI/YM-PMPCS had superior wear resistance than that of YM-PMPCS at elevated temperature and with electrical current. At elevated temperature, the wear mechanism of tribological pair evolved from adhesive wear to oxidative wear with mild delamination wear. Arc erosion wear, oxidative wear, and adhesive wear were the dominant mechanisms of tribological pair during the electrical wearing process.