稀土化合物改性复合材料在油润滑下的摩擦学性能

以竹纤维为增强相,通过稀土化合物改性制备一种树脂基复合材料;采用环块式摩擦磨损实验,研究稀土化合物改性复合材料在油润滑状态下载荷、转速对试样摩擦学性能的影响,以及稀土化合物改性对复合材料试样摩擦学性能的影响;比较干摩擦状态和油润滑状态下复合材料的摩擦学性能,观察和分析试样磨损表面形貌,探讨其磨损机制。实验结果表明:油润滑条件下,稀土化合物改性复合材料的摩擦因数和磨损率都随着载荷的增大而增加;较高载荷下摩擦因数随着转速的增大先增加后减小,而磨损率则呈现逐步增加的趋势;稀土化合物的改性使竹纤维和基体界面结合更为紧密,提高摩擦因数的同时降低了磨损率;在油润滑作用下,试样磨损由干摩擦时的磨粒磨损和疲劳磨损转变成为轻微的疲劳磨损;在油润滑状态下,复合材料处于边界润滑状态,故摩擦因数和磨损率均低于干摩擦。     

Friction and wear behavior of Ni-P coated Si3N4 reinforced Al6061 composites

Al6061 matrix composite reinforced with nickel coated silicon nitride particles were manufactured by liquid metallurgy route. Microstructure and tribological properties of both matrix alloy and developed composites have been evaluated. Dry sliding friction and wear tests were carried out using pin on disk type machine over a load range of 20-100 N and sliding velocities of range 0.31-1.57 m/s. Results revealed that, nickel coated silicon nitride particles are uniformly distributed through out the matrix alloy. Al6061-Ni-P-Si₃N₄ composite exhibited lower coefficient of friction and wear rate compared to matrix alloy. The coefficient of friction of both matrix alloy and developed composite decreased with increase in load up to 80 N. Beyond this, with further increase in the load, the coefficient of friction increased slightly. However, with increase in sliding velocity coefficient of friction of both matrix alloy and developed composite increases continuously. Wear rates of both matrix alloy and developed composites increased with increase in both load and sliding velocity. Worn surfaces and wear debris was examined using scanning electron microscopy (SEM) for possible wear mechanisms. Energy dispersive spectroscope (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscope (XPS) techniques were used to identify the oxides formed on the worn surfaces and wear debris.     

Friction and wear behavior of electroless Ni-based CNT composite coatings

Ni-based carbon nanotube (CNT) composite coatings with different volume fraction (from 5 to 12 vol.%) of CNTs were deposited on medium carbon steel substrates by electroless plating. The friction and wear behavior of the composite coatings were investigated using a pin-on-disk wear tester under unlubricated condition. Friction and wear tests were conducted at a sliding speed of 0.0623 m s⁻¹ and at an applied load of 20 N. The experimental results indicated that the friction coefficient of the composite coatings decreased with increasing the volume fraction of CNTs due to self-lubrication and unique topological structure of CNTs. Within the range of volume fraction of CNTs from 0 to 11.2%, the wear rate of the composite coatings showed a steadily decreasing trend with increasing volume fraction of CNTs. Because of the conglomeration of CNTs in the matrix, however, the wear rate of the composite coatings increased with further increasing the volume fraction of CNTs.     

Ekonol/石墨/MoS2填料对PTFE力学和摩擦磨损性能的影响

研究了Ekonol含量对Ekonol／石墨／MoS2／P，PTFE复合材料的力学性能、摩擦磨损性能的影响，以及滑动速度、载荷对材料摩擦磨损性能的影响；用扫描电子显微镜观察了复合材料磨损后的表面形貌，并探讨了其磨损机制。结果表明：加入填料降低了材料的拉伸强度和弯曲强度，但提高了弯曲模量和硬度；同时填料能提高材料的磨损性能，但使摩擦因数升高了；当Ekonol含量较低时，磨损机制为粘着磨损，随着填料含量的增加，Ekonol分散到基体中，起到了承载作用，阻止了PTFE基体的带状破坏，磨损机制为疲劳磨损和轻微的粘着磨损；摩擦因数随载荷的增大而减小，随滑动速度的增大而增大，在相同的滑动时间内，磨痕宽度随载荷和滑动速度的增大而增大。     

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.     

Friction and wear behavior of three-dimensional braided carbon fiber/epoxy composites under dry sliding conditions

Sliding friction and wear characteristics of three-dimensional (3-D) braided carbon fabric reinforced epoxy resin (C_3D/EP) composites were investigated. Tests were performed on a MM200 tester under normal loads of 50, 150, and 250 N and velocities of 0.42 and 0.84 m/s. A quenched medium carbon steel with a hardness of HRC 52 was used as the counterpart material. The specific wear rate and the coefficient of friction were examined as a function of testing conditions (load, velocity, and sliding distance) and material parameters (fiber volume fraction and fiber–matrix bonding). The results showed that the coefficient of friction and the specific wear rate changed considerably during the running-in period and reached stable values at the steady wear stage. Fiber volume fraction and testing conditions (load and velocity) affected the wear more significantly than the friction. It was also found that fiber–matrix bonding had an impact on the friction and wear of the 3-D composites. Furthermore, the specific wear rate decreased with the increase in the product of load and velocity. Worn surfaces and debris were observed by scanning electron microscope (SEM) and wear mechanisms were discussed in this study.     

水润滑橡胶轴承摩擦磨损性能的研究

以丁腈橡胶（ＮＢＲ） 为基体,制备水滑润橡胶轴承;研究填料、载荷、转速、润滑介质、ＮＢＲ品种等因素 对橡胶轴承在水润滑介质中的摩擦磨损性能的影响,并分析其摩擦和磨损机制。结果表明,炭黑量和二硫化钼添加量明 显影响橡胶轴承的摩擦因数和磨损量;随着载荷的增大,橡胶轴承的摩擦因数和磨损量均呈现先增大后减小再明显增大 的趋势;随着转速的增大,橡胶轴承的摩擦因数和磨损量均明显减小,并且在海水中的摩擦因数和磨损量均大于在淡水 中的摩擦因数和磨损量。     

载荷和转速对HDPE多元复合材料摩擦学性能的影响

为改善高密度聚乙烯(HDPE)的力学性能、自润滑性和耐磨性,以HDPE为基体,通过填充六钛酸钾晶须(PTW)、聚四氟乙烯(PTFE)和滑石粉制备一种HDPE复合材料.在MMW-1型摩擦磨损试验机上测试复合材料在不同载荷和转速下的摩擦因数、磨损率,采用扫描电镜(SEM)分析磨痕形貌,探讨HDPE复合材料的摩擦磨损规律.结...     

Comparative investigation on the tribological behaviors of CF/PEEK composites under sea water lubrication

Carbon fiber (CF) reinforced polyetheretherketone (PEEK) composites were prepared and their tribological behaviors under sea water lubrication were comparatively investigated. The results showed that the incorporation of CF can greatly improve the wear resistance of PEEK under sea water lubrication, especially when the volume fraction of CF was about 10%, because exposed CF can effectively share the main load between the contact surfaces and consequently protect the matrix from severe wear. In addition, CF/PEEK had better friction and wear properties under sea water lubrication than under dry friction and pure water lubrication due to better lubricating effect of sea water.     

纳米SiO2颗粒和玻璃微珠共混改性超高分子量聚乙烯复合材料的摩擦磨损性能

采用模压成型工艺制备了纳米SiO2颗粒和玻璃微珠共混改性的超高分子量聚乙烯复合材料;研究了相对滑动速度、载荷以及玻璃微珠含量对复合材料摩擦磨损性能的影响,并对磨损形貌和磨损机理进行了分析。结果表明:添加纳米SiO2颗粒和玻璃微珠可以提高复合材料的硬度、压缩弹性模量和摩擦磨损性能;相对滑动速度对复合材料摩擦因数和磨损率有很大的影响;载荷对复合材料的摩擦因数影响不明显,但磨损率随载荷的增加而增大;纳米SiO2颗粒和玻璃微珠混合改性后复合材料的磨损机理主要是粘着磨损和疲劳磨损。     

高水基液压阀陶瓷摩擦副摩擦学性能研究

为选择适合的高水基乳化液液压阀摩擦副材料,探讨ZrO2与不同结构陶瓷组成的摩擦副在高水基乳化液润滑状态下的摩擦磨损特性。采用摩擦磨损试验机,在不同载荷和滑动速度下,研究在高水基乳化液介质中4种不同陶瓷材料（ZrO2、Al2O3、Si3N4和SiC）分别与ZrO2配副的摩擦学性能,并探讨不同组合陶瓷摩擦副的磨损机制。结果表明：在高水基乳化液中,各陶瓷的摩擦因数均随着滑动速度的增大而降低,其中Al2O3陶瓷的摩擦因数最小;ZrO2、Al2O3和Si3N4陶瓷的摩擦因数受载荷的影响较小,SiC陶瓷的摩擦因数则随着载荷的增大而骤增;各陶瓷的磨损体积都随着速度和载荷的增大而增大,其中Al2O3/ZrO2陶瓷摩擦副的磨损体积最小,其磨损机制以磨粒磨损和微疲劳磨损为主。研究表明,在不同工况下,Al2O3与ZrO2陶瓷配副的摩擦因数和磨损体积均为最低值,更适合作为高水基乳化液液压阀的摩擦副材料。     

腐蚀介质条件下NiCrBSi/WC喷熔层的摩擦学性能研究

采用氧-乙炔火焰喷熔工艺,制备了碳化钨颗粒增强镍基合金喷熔层(NiCrBSi/WC),研究了它在腐蚀介质条件下的摩擦磨损行为与机理,并考察了载荷、滑动速度对其摩擦磨损性能的影响规律。研究结果表明:NiCrBSi/WC具有良好的耐腐蚀磨损性能,且当WC含量为20%时,腐蚀磨损率最低;WC含量超过20%后,由于喷熔层存在“腐蚀原电池”效应,其腐蚀磨损率增大。NiCrBSi/WC的腐蚀磨损率随载荷增加而变大,随速度增大而减小。载荷的增加使喷熔层的犁削磨损加剧,导致摩擦系数和磨损率增大;速度的增大造成摩擦界面温度上升,可生成摩擦转移膜,从而降低了喷熔层的磨损率。     

Tribological behavior of metal matrix composites

The wear and friction behavior of continuous graphite fiber reinforced metal matrix composites was investigated. Composite materials were tested against 4620 steel at 54 m s^?1 at room temperature in air without lubricant. The graphite fibers studied included rayon-, pitch- and polyacrilonitrile (PAN)-based fibers. Both high modulus and high strength PAN-based fibers were examined. The fibers were incorporated into copper- and silver-based alloys by means of a liquid metal infiltration technique. The results of this study indicate that the type of graphite fiber in the composite is the most significant factor in the wear and friction behavior of metal matrix composites. In some high modulus fiber tin-bronze composites the fiber fraction influences the wear rate but not the coefficient of friction. Neither the matrix alloy nor the composite tensile strength per se correlate with the friction and wear properties; however, there are specific trends for the various matrix alloys.     

Wear and friction behavior of sand cast brake rotor made of A359-20 vol% SiC particle composites sliding against automobile friction material

The effect of load range of 30-100 N and speed range of 3-12 m/s on the wear and friction behavior of sand cast brake rotor made of A359-20 vol% SiC particle composites sliding against automobile friction material was investigated. Dry sliding frictional and wear behavior were investigated in a pin-on-disc type apparatus. Automobile friction material was used as pin, while the A359-20 vol% SiC particle composites formed the rotating disc. For comparison, the wear and friction behavior of commercially used cast iron brake rotor were studied. The results showed that the wear rate of the composite disc decreased with increasing the applied load from 30 to 50 N and increased with increasing the load from 50 to100 N. However, the wear rate of the composite disc decreased with increasing the sliding speed at all levels of load applied in the present work. For all sliding speeds, the friction coefficient of the composite disc decreased with applied load. The worn surfaces as well as wear debris were studied using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) analyzer and X-ray diffraction (XRD) technique. At load of 50 N and speed range of 3-12 m/s, the worn surface of the composite disc showed a dark adherent layer, which mostly consisted of constituents of the friction material. This layer acted as a protective coating and lubricant, resulting in an improvement in the wear resistance of the composite.     

Fe3Al基摩擦材料烧结性能及摩擦学特性初探

用球磨机械合金化工艺制备Fe3Al粉末,采用粉末冶金工艺,选择不同的烧结温度、烧结压力和保温时间,获得Fe3Al基复合材料的最佳烧结工艺条件。对最佳工艺条件获得的材料的物理机械性能、摩擦磨损性能和微观结构进行分析测试,借助磨损表面扫描图像和能谱分析,分析该材料的磨损形式,并探讨该材料在低速低载和高速重载2种工况条件的磨损机制。结果表明:采用烧结温度为1 100℃,烧结压力为10 MPa下保温30 min的工艺条件烧结的材料有较好的机械性能和摩擦磨损性能。其摩擦磨损机制为:低速低载以疲劳磨损和磨粒磨损为主,高速重载以疲劳磨损和磨粒磨损为主,并伴有轻微的黏着磨损形式。     

Comparison on abrasive wear of SiCrFe, CrFeC and Al2O3 reinforced Al2024 MMCs

The effects of volume fraction and size of SiCrFe, CrFeC, and Al₂O₃ particulates on the abrasive wear rate of compo-casted Al2024 metal matrix composites (MMCs) were studied. The process variables like the stirring speed, position and the diameter of the stirrer have affected the diffusion between particulates and matrix.The abrasive wear rate was decreased by the increase in particulate volume fraction of SiCrFe and CrFeC intermetallic reinforced composites over 80 grade SiC abrasive paper. The wear rates of the all composites decreased with aging treatment, and the best result was seen for the composite having a hybrite structure as SiCrFe and CrFeC particulates together. Nevertheless, the fabrication of composites containing soft particles as copper favors a reduction in the friction coefficient.     

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。     

The effect of sliding time and speed on the wear of composite materials

The friction and wear properties of an Al 201 alloy and a unidirectionally oriented graphite fiber-aluminum matrix composite (T50-Al 201) were investigated. The experiments were conducted on a pin-on-disc type friction machine. The diameter of the pin was 0.22 cm and the load 4.46 N. The sliding velocity varied between 0.17 and 0.43 m s^?1. The disc counterface was of commercially pure iron. It has been found that the friction coefficient μ and the wear rate W_L of the composite material decrease as the sliding time is increased until a steady state value is reached. The steady state wear rate is proportional to the reciprocal of the sliding speed in accord with a recently proposed model. Scanning electron microscopy and Auger electron spectroscopy observations indicate that the high initial values of μ and W_L are due to a high degree of matrix adhesion to the counterface accompanied by fiber breaking and transfer. The low steady state values of μ and W_L are due to the formation of a film that impedes adhesion and confers some degree of self-lubrication. It is suggested that the observed variation of W_L with sliding speed is related to changes in the degree of subsurface damage as the velocity is varied.     

干摩擦工况下Si3N4/PTFE配副材料摩擦磨损特性与转移膜形成分析

为使全陶瓷轴承在干摩擦工况下可靠运转,选用四氟乙烯(PTFE)材质的保持架为全陶瓷轴承提供润滑.利用Rtec销/盘摩擦磨损试验机,以PTFE盘与氮化硅(Si3 N4)销为摩擦副,研究Si3 N4/PTFE在不同载荷和转速条件下的摩擦磨损性能,通过SEM对Si3 N4表面的转移膜形貌进行观察,分析转移膜形成原因.结果表明...     

稀土强韧化MoSi2材料的摩擦学性能

采用高温自蔓延和真空烧结合成了含0.8%（质量分数）稀土/MoSi2复合材料。在MRH-5A型环-块摩擦磨损试验机上,考察了其与调质45#钢配对时的摩擦磨损特性。运用带有微探针的KYKY2800型扫描电镜分析了其磨损表面形貌,探讨了该材料的磨损机制。结果表明：在干摩擦同等条件下,稀土/MoSi2复合材料比纯MoSi2材料具有更好的抗磨损性能,其磨损率比纯MoSi2至少降低了68%。低速（200r/min）时,RE/MoSi2复合材料的磨损机制主要是粘着磨损,随着载荷的增加,粘着磨损脱落更为严重;在高速（400r/min）和低载荷（78N）下,RE/MoSi2复合材料的磨损机制仍以粘着磨损为主,在重载荷（274N）下,RE/MoSi2复合材料的磨损机制主要为粘着磨损和疲劳脆性断裂。