Dry sliding wear behavior of MoSi2-Mo5Si3-Mo5SiB2 composite at different temperatures and loads

Abstract

Abstract MoSi2-Mo5Si3-Mo5SiB2 composite is a kind of potential wear resistance material in high temperature environments. However, it is not yet understood how the dry sliding wear properties of the composite. In this work, a series of ball (Si3N4)-on-disk (composite) sliding wear tests were conducted to evaluate the tribological properties of the composite at different temperatures and loads. The results show that the temperature and load have a slight influence on the wear rate of the composite, while the coefficient of friction (COF) is strongly dependent on the temperatures and loads. The COF and wear rate are (0.34–0.62) and (6.4–7.5)\u202f×\u202f10−6 mm3N−1m−1\u202fat 25–1000\u202f°C, respectively. The wear mechanism is dominated by the brittle fracture wear below 400\u202f°C, then transforms to the oxidative wear (600–1000\u202f°C), and the plastic deformation (1000\u202f°C). In additional, the increasing loads (2.5–10\u202fN) lead to a severer plastic deformation tribolayer on the worn surface, which causes low COFs (0.30–0.56) as well as low wear rates (7.38–7.54\u202f×\u202f10−6 mm3N−1m−1) at 1000\u202f°C, and the corresponding wear mechanisms exhibit the adhesive and oxidation wear. The composite shows a promising application as tribological components at elevated temperature in oxidizing environment owing to the development of a protective oxide layer or a plastic deformation tribolayer on the top of the wear surface.