In-situ Synthesis of WC/TaC Reinforced Nickel-Based Composite Alloy Coating by Laser Cladding

An in-situ synthesized WC/TaC reinforced nickel-based composite coatings have been fabricated on AISI 1045 mild carbon steel substrate by laser cladding of powder mixture of Ni60/WC with Ta2O5 and graphite. The microstructure and hardness distribution of WC/TaC/Ni60 composite coating were investigated by scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. Results show that the microstructure of the coating has a metallurgical bonding with substrate and is mainly composed of γ-Ni dendrites, W2C, M7C3 carbides, and dispersed TaC particles. The hardness HV of WC/TaC/Ni60 composite coating has been enhanced to a value similar to 9650 MPa, which is 1.3 times higher than that of Ni60 coating. Measurement results demonstrate that these improvements are attributed to the presence of in-situ synthesized TaC particles, microstructure change and phase variations.