Dry sliding wear behaviors of La2O3–WSi2–MoSi2 composite against alloy steel

A molybdenum disilicide (MoSi₂) matrix composite with the addition of WSi₂ and La₂O₃ (RWM) was fabricated as a wear resistant material by self-propagating high temperature synthesis (SHS) and hot pressing (HP). This composite was analyzed by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The wear resistance of MoSi₂ against steel is significantly improved by the addition of both WSi₂ and La₂O₃, and it is attributed to the increase in hardness and toughness of the composite. It is found that the wear behavior of the RWM is sensitive to sliding speed, load and hardness of the counter-face material. When worn against a steel with a lower hardness (A), the wear rate of RWM increases with an increase of sliding speed, and increases initially and then decreases with an increase of load. The material removal mechanisms varied from ploughing wear at low load and speed to serious adhesive wear at high load and speed. When worn against a steel with a higher hardness (B), the wear resistance of the RWM improved and the material removal mechanism were brittle fracture wear at low speed and adhesive wear at high speed.