选取尺寸为01076～01100mm的WC颗粒为增强相，45钢为基体，系统地研究了粉末冶金真空烧结法制备颗粒增强钢基复合材料的温压烧结工艺，考察了常温压制烧结和温压烧结两种工艺条件下材料的滑动摩擦磨损性能。结果表明：对于50%WC+50%45钢（质量分数）粉末，采用硬脂酸锌作润滑剂，在压制温度为140℃、压力为320kN时，得到了较为理想的压坯密度（914362g/cm3），其相对密度达到9116%，比常温压制的压坯密度（911292g/cm3）提高了314%。销盘磨损试验结果表明：温压试样的耐磨性分别是15Cr高铬铸铁的219倍，20Cr高铬铸铁的216倍，同样工艺条件下常温压制试样的218倍，通过扫描电镜分析了复合材料的磨损机理。

In order to overcome the shortcomings of present switch slide baseplates, a kind of epoxy composite was designed as lubricating coatings for switch slide baseplates. The wear tests of epoxy composite specimens paired with A36 steel specimens under air-lubricated condition were carried out on a ring–block wear tester typed M200. After the wear tests, the worn surfaces of steel specimens were examined by XPS and SEM. Furthermore, the wear reduction mechanism of graphite and MoS2 was discussed. The results showed that the graphite in epoxy composite can reduce the friction coefficient effectively, and increase the wear resistance of the epoxy composite greatly. MoS2 in epoxy composite is translated to MoO3 during the wear tests. Consequently, the friction coefficient of the pair cannot be decreased because MoO3 has not a layer structure. But MoS2 can effectively improve the wear resistance of the composite through restraining the epoxy transfer from the surface of composite to the surface of A36 steel.

Using distilled water and air lubricants, wear tests of ceramic-cast iron pairs were carried out on a M-200 type ring-block wear tester. For comparison, ceramic-carbon steel pairs were also tested under the same conditions. The worn surfaces of specimens were observed under scanning electron microscope (SEM) and optical microscope. Furthermore, the tribofilms were analyzed by using Augerelectron spectroscopy (AES), energy-dispersive X-ray spectroscopy (EDX) and image analysis technique. In the wear tests of Si3N4-cast iron pairs lubricated with distilled water, the friction coefficients of the pairs are just 0.02, and the wear rates of ceramic and iron are near zero. The superior triboiogical eharaeteristics are due to a tribochemical film. which is formed on the wearing surfaces and has sufficient thickness and area. However, in the test of a Si3N4-carbon steel pair lubricated with distilled water, the friction coefficient is still high because the tribochemicai film formed on the wearing surface is too thin and too small. A metal transfer film is formed on the ceramic surface when the ferrous metals slide against Al2O3. In this situation, the wear amount of Al2O3 is quite small, but the wear amount of the metals is large and the friction coefficient is rather high.

A tribofilm was formed during wear tests of a Si3N4-gray iron pair lubricated with distilled water. In order to clarify the formation process Of the film, wear tests of fhe Si3N4-gray iton pair with different sliding distances were carried out on a ring-block tester using distilled water as iubricant. After the tests, the worn surfaces of the gray iron specimens were examined under SEM. Furthermore, the components and the structure of the film were analyzed by AES, XPS, FTIR and XRD. Combining the obtained results, the following aspects are obtained. During the wear tests of a Si3N4-gray iron pair lubricated with distilled water, oxidation and hydrolysis of Si3N4 occur on the wearing surfaces, and the reaction product may be adsorbed by graphite flakes in the iron. As a result, a tribochemical film with a certain thickness and area, which consists of silicagel and graphite, is formed on the wearing surface. The film protects both Si3N4 and gray iron and makes the paired surfaces smooth. Therefore. the friction coefficient of the pair iS lowered down to as low as 0.002, and the total wear rates of Si3Na and Iron are near zero. However, because the products of oxidation and hydrolysis of Si3N4 cannot be accumulated on the wearing surface of carbon steel to form an eflfective tribofilm, both the friction coeffcient and the wear rate of the Si3N4-carbon steel pair lubricated with distilled water are high.

针对我国传统铁路滑床板在应用过程中存在的浪费和污染问题，研制了环氧树脂基减摩复合材料涂层以替代润滑油层，改善滑床板的性能。在M200环块磨损试验机上考察了复合材料中减摩相对复合材料-钢摩擦学特性的影响，对磨损后的钢试样表面进行了X光电子能谱分析与扫描电镜观察，对石墨与MoS2的减摩作用机理进行了探讨。结果表明：复合材料中添加石墨可有效降低摩擦副的摩擦系数，大幅度提高复合材料的耐磨性；MoS2在摩擦过程中发生氧化转变为MoO3，失去了层状结构，因而不能降低摩擦系数，但同时MoS2抑制了树脂向钢试样表面的转移，可有效提高复合材料的耐磨性。