Microstructure, hardness, and wear resistance at room and high temperature of Stellite-6/WC-6Co coatings deposited by laser cladding process

Research have focused on finding solutions to prolong the life of metal parts which suffer damage from wear. Hard facing is a suitable solution, and Co-based alloys and ultimately metal matrix composites have been used due to their high wear resistance. In this work, the wear resistance at room temperature (RT) and at 600 °C of Stellite-6/WC-6Co coatings obtained by laser cladding was evaluated, deposited using continuous (CW) and pulsed wave (PW), and varied the idle time. The coatings deposited with CW showed higher hardness in the matrix (785-843 HV); meanwhile, the PW showed values between 623 and 786 HV. The increase in hardness was attributed to the higher W and C diffusion toward the matrix. The use of PW reduced diffusion due to the higher cooling rates. Similarly, coatings deposited with CW obtained the best wear resistance in both temperature conditions, with values between 11.81 × 10⁻⁶ mm³/Nm and 39.39 × 10⁻⁶ mm³/Nm, respectively. At RT, W and C diffusion promoted the formation of carbides that had a lubricating effect; however, at a high temperature, tribo-oxidation occurred with the formation of protective layers of oxides. Stellite-6/WC-6Co coatings showed good wear resistance, which makes them an alternative to improve the useful life of metallic components.