Effect of MoS2 on Iron-Based Friction Material Prepared Directly from Vanadium-Bearing Titanomagnetite Concentrates

Abstract

The iron-based friction material was prepared directly from vanadium-bearing titanomagnetite concentrates by in situ selective carbothermic reactions and sintering process. This paper studies the effects of MoS2 addition (1–4 wt%) on the microstructure and properties of iron-based friction material. The results show that the addition of MoS2 greatly improves the microstructure and properties of the material. During the sintering process, MoS2 reacts with Fe to produce new lubricating phase FeS and Mo which is dissolved in the Fe matrix. Appropriate amounts of FeS and Mo promote the sintering densification, which improves the microstructure by reducing the number of pores, as well as making the hard particles and graphite distribute evenly. In addition, Mo could facilitate the formation of lamellar pearlite. As a result, the relative density, hardness and tribological properties are significantly enhanced. Particularly, the friction coefficient decreases from 0.55 to 0.36–0.48 and the wear rate decreases from 1.899 × 10−7 to 0.673 × 10−7–1.653 × 10−7 cm3/J when MoS2 is added. However, excessive MoS2 deteriorates both the microstructure and properties of the material. The material containing 2 wt% MoS2 represents the optimum properties.