Microstructure of laser-clad high-temperature self-lubricating wear-resistant composite coatings

摘要

Abstract: In this paper, a 5 kW cw CO$-2$/ laser was used to fabricate a new high-temperature self-lubricating wear-resistant composite coating on austenite stainless steel 1Cr18Ni9Ti. Microstructure of the coatings was characterized by OM, SEM, XRD and EDS as functions of laser processing parameters. The hybrid composite coating consists of rapidly solidified wear-resistant primary Cr$-7$/C$-3$/ and eutectic Cr$- 23$/C$-6$/ carbides, high-temperature self-lubricating CaAgF$-4$/ or CaF$-2$/ particles and the oxidation-resistant austenitic Ni-Cr matrix. Microstructure and hardness within the whole laser clad composite coating is homogeneous and the bonding to the substrate is purely metallurgical. Microhardness of the composite coating is 700 approximately 1000 HV on average. The hybrid composite coatings fabricated by laser cladding are expected to have good high-temperature tribological properties.!7