Friction and wear behaviors of MoAlB-0.1Si ceramic composite with superior comprehensive properties from RT to 800 °C

MoAlB-0.1Si ceramic composite (Si0.1) has been prepared by hot-pressing sintering method. The microstructure, mechanical properties as well as tribological properties from room temperature(RT) to 800 °C have been systematically investigated with the aid of SEM, EDS, XRD and XPS. The results show that Si0.1 has much better wear resistance than MoAlB without Si addition(Si0) when sliding against IN718 and Si₃N₄ counterparts at all temperatures. With the temperature increasing from RT to 800 °C, the coefficient of friction (COF) and wear rate gradually decreases; and the wear rate of Si0.1 decrease by 92.9 % and 82.8 %, respectively. In case of IN718 counterpart, smooth tribo-layers can be formed on the wear surface; the main wear mechanism transforms from surface fracture at RT to oxidation wear at high temperature. Consequently, the lowest COF of 0.34 and wear rate of 3.504 × 10⁻⁶ mm³ (N m)⁻¹ can be obtained when wear against IN718 at 800 °C. In case of Si₃N₄, tribo-layers are hardly formed on the wear surface; the main wear mechanism transform from abrasive wear and surface fracture at RT to oxidation wear at high temperature. The higher hardness, fracture toughness as well as better oxidation resistance contribute to the superior tribological performance of Si0.1.