Preparation and Friction-Wear Property of Mo₅Si₃-20% Al₂O_3p Ceramic Composite

Mo₅Si₃ cermet and Mo₅Si₃-20wt% Al₂O_3p ceramic composite were prepared by mechanical milling and hot-pressing sintering. And then the microstructure, mechanical and friction-wear properties were analyzed by using X-ray diffractometer, scanning electron microscopy, hardness tester, friction-wear testing machine, etc. The results show that the Mo₅Si₃-20wt% Al₂O_3p ceramic composite was mainly composed of Mo₅Si₃, Al₂O₃ and few Mo₃Si phases. The relative density, hardness and fracture toughness of the ceramic composite were higher than those of the single-phase Mo₅Si₃ cermet. Furthermore, the friction coefficient and wear rate of the ceramic composite were lower and the changing of friction coefficient with the time was smoother, showing a better friction and wear resistance. When grinding with GCr15 steel ball, the main wear mechanism of the Mo₅Si₃ cermet was adhesive wear and spalling fatigue, while that of Mo₅Si₃-20wt% Al₂O_3p ceramic composite was abrasive wear. Both had an oxidation wear.