Effects of the interface structure on the mechanical and tribological properties of the MoS2/CuCr composites

Abstract

High-strength wear-resistant materials have gained significant attention in current research. molybdenum disulfide (MoS2), as a solid self-lubricating material for reinforcing copper(Cu)-based composites, has become a focal point for researchers. However, the reaction between MoS2 and Cu during high temperature sintering leads to the formation of brittle phase, which compromises the interfacial bond. Therefore, this study attempts to improve the interfacial structure by introducing chromium (Cr) element through CuCr alloying with the expectation of mechanical and tribological properties improvement. Spark plasma sintering (SPS) is employed to prepare MoS2/CuCr composites and the effects of different MoS2 contents (0–10 wt%) under various normal loads on frictional wear will be evaluated. The results demonstrate that Cr element addition facilitates the formation of compact Cr3S4 compounds with MoS2 at the interfaces, enhancing interfacial bonding with Cu and providing a solid foundation for maintaining excellent wear resistance during friction processes. With increasing content of MoS2, both coefficient of friction (COF) and wear rate initially decrease and then show an upward trend. Under the normal load of 20 N, compared with the CuCr composite, the friction coefficient of the composite with 7.5 wt % MoS2 content is 0.281, which is significantly reduced by 37.7 %, and the wear rate is 0.1471( × 10−3 mm3/N.m), which is reduced by 50.9 %. This research content can provide a better theoretical basis for changing the problem of poor wettability between the lubricating phase and the matrix.

Keywords

• Copper matrix composites
• MoS2
• Interface structure
• Wear-resistant property