Study on the microstructure and properties of Cu-graphite-Cr3C2 composites prepared by in-situ reactive synthesis

Abstract

Cu-graphite-Cr3C2 composites were synthesized via spark plasma sintering (SPS) using different gas environments, including argon and air, to blend the raw materials consisting of Cr2AlC, Cu-coated graphite, and pure Cu. The microstructure and physical properties of the composites were thoroughly investigated. The findings revealed that Cr3C2, synthesized in situ from Cr2AlC, was firmly embedded in the Cu matrix. Additionally, a layer of Cr3C2 was formed at the interface between the Cu matrix and graphite. The composites showed a high relative density, which above 96 %. The composites fabricated with the raw materials mixed in an argon gas environment had a hardness of 72.6 HSD and an electrical conductivity of 1.102 × 106 S·m−1. Whereas, the hardness and electrical conductivity of the composites fabricated with the raw materials mixed in an air gas environment increased to 75.6 HSD and 1.314 × 106 S·m−1, respectively. Furthermore, Cu-graphite-Cr3C2 composites fabricated with the raw materials mixed in air rather than argon exhibited better lubrication performance and wear resistance, the average friction coefficient and wear rate were measured to be 0.4644 and 2.682 × 10−7 mm3/N·m, respectively.