Surface modification of Cr3C2–NiCr cermet coatings by direct diode laser

Thermal spraying has emerged as an important tool of increasingly sophisticated surface engineering technology, and it is being used widely to repair and surface modification in metallic parts. The Cr₃C₂–NiCr sprayed coatings are frequently used as wear resistant coatings against abrasion and erosion at high temperature up to 1173 K, and in corrosive environments. Hardness and microstructure of Cr₃C₂–NiCr cermet coatings fused by direct diode laser process was compared with that formed by high-velocity oxygen fuel spraying (HVOF) process. The effect of beam characteristics (power density, power, scanning speed, etc.) was examined on the surface modification of sprayed coatings. In this study, we treated Cr₃C₂–25%NiCr cermet coatings by laser irradiation process and examined its hardness compared with that formed by HVOF process. Consequently, the average hardness of laser-treated Cr₃C₂–25%NiCr cermet coatings has been found out to be higher than that of HVOF coatings. Laser remelting improved markedly the wear resistance of HVOF sprayed Cr₃C₂–25%NiCr cermet coatings.