含MoS_2镍基合金高温磨损机理

High-temperature wear mechanism of Ni-based alloy containing MoS_2

用粉末冶金方法制备了镍基复合材料,在销盘式高温磨损试验机上研究了其从室温到600℃的磨损行为,采用XRD和光学显微镜等对试样磨损表面和磨屑的形貌、成分和结构进行了分析,探讨了镍基复合材料的高温磨损机理。结果表明:在室温下由于摩擦过程中材料产生晶粒细化,材料具有一定的抗磨减摩性能;200℃时,摩损表面氧化变软,没有成膜润滑能力,摩擦学性能与室温相比,没有太大的变化,材料表现为轻微的粘着磨损和塑性变形;600℃高温摩擦时,承载表面及磨屑中的氧化物、钨酸盐及残余硫化物的高温软化或熔化的协同作用,在表面形成润滑膜,改善了材料的润滑性能,摩擦因数明显降低,材料的磨粒磨损和不断氧化导致磨损增加。

Ni-Cr-based alloy was prepared by powder metallurgy technique. The wear mechanism of the alloy was investigated by pin-on-disk apparatu at high temperatures. The worn surface of the Ni-based composite and the wear debris were analyzed by means of optical microscope and XRD. The results show that the formation of fine-grained microstructure on the worn surfaces in the process of friction is responsible for reduction of friction at room temperature. At 200~C, the triholngieal properties are almost the same as those at room temperature due to no beneficial trihofihn forming on the surface. The worn surface of the alloy shows mild adhesive wear and plastic deformation. At 600~C, the friction coefficient is reduced due to the effect of the oxides, tungstates and sulfides residue on the worn surface, however, the abrasive wear and continuously oxidation leads to high wear rate.