Microstructure and high temperature reciprocating sliding wear properties of MoSi2/TiC/γ-Ni composite coating in-situ synthesized by co-axial powder feeding plasma transferred arc cladding

A MoSi2/TiC/γ-Ni high temperature wear-resistant composite coating was in-situ synthesized on AISI 321 substrate by co-axial powder feeding plasma transferred arc (PTA) cladding process using powders blend of Ni, Ti, Mo, Si and Ni-P coated graphite as raw material. Microstructure and in-situ synthesis mechanism of the composite coating was analyzed. High temperature tribological properties of the coating were evaluated. Test results show that the composite coating has refined microstructure consisting of MoSi2, TiC and γ-Ni. TiC and MoSi2 as in-situ synthesized reinforcing phases are uniformly scattered in the γ-Ni/TiC binary eutectic matrix. Benefiting from the unique microstructure, the coating exhibits high hardness, low and stable friction coefficient values and good high temperature reciprocating sliding wear resistance.