A CeO2-Doped Copper Matrix Self-Lubricating Composite With Well-Balanced Mechanical and Lubricating Properties Fabricated by Spark Plasma Sintering

Abstract Metal matrix self-lubricating composites are required to possess well-balanced mechanical and lubricating properties when they are applied as mechanical parts. However, the decomposition of disulfide lubricants usually occurs during the sintering process and unfortunately reduces their mechanical properties. In this work, CeO 2 was added to a model Cu/WS 2 composite fabricated by spark plasma sintering (SPS). The effect of CeO 2 doping on the interfacial microstructure and mechanical and tribological properties was investigated. The results indicated that CeO 2 nanoparticles preferentially adsorbed onto the lubricant disulfide, which segmented the Cu/WS 2 diffusion layer and reduced Joule heat at the interface while competing with WS 2 to intensify the heat dissipation. As a consequence, interfacial overheating was largely suppressed, and WS 2 decomposition was successfully prevented. The CeO 2 -doped Cu/WS 2 composite breaks through a trade-off between mechanical and lubricating properties, exhibiting a high bending strength of 295.1 MPa, a hardness of 98.5 HV, a low friction coefficient of 0.19, and a wear rate as low as 4.12 × 10 −5 mm 3 /N m. Graphical Abstract