Preparation and Mechanical Wear Behavior of MoSi2–Al2O3 Composite

Abstract

Using MoO₃, Mo, Al and Si powders as raw materials, MoSi₂ and MoSi₂–Al₂O₃ composite were prepared by mechanochemical reduction and hot press sintering techniques. The microstructure and dry sliding wear behavior of the samples were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and a ball-on-disk reciprocating tribometer. The results showed that MoSi₂–Al₂O₃ composite has a fine microstructure, high hardness (13.4 GPa) and fracture toughness (7.2 MPa m^0.5) compared to the pure MoSi₂ material. The wear test results indicated that MoSi₂ and MoSi₂–Al₂O₃ composite exhibited good tribological properties against sliding GCr15 steel balls under different loads. The friction coefficient and wear rates of the samples decreased as the applied load increased. Compared to pure MoSi₂, MoSi₂–Al₂O₃ composite exhibited better wear resistance due to its high hardness, fracture toughness and good surface lubrication characteristics. The dominant wear mechanisms of the composite were adhesion, tribo-oxidation, plastic deformation and spalling.