Microstructure and Wear Properties of Wide-Band Laser Re-Melted WC-Co Ceramic Coating

Wide-band CO2 laser cladding of thermal sprayed WC-Co ceramic coatings was performed, the microstructures and phase compositions of the cladding layers were analyzed, the hardness distribution and wear properties were measured, and the processing parameters on the phase and hardness of the coating were discussed. Laser re-melted coating consisted of WC, C, CW3, Co6W6C and CCo2W4. A higher laser power dissolved and decomposed WC, which was crucial to the performance of the coating. Meanwhile, a higher scanning speed contributed to the hardness of the coating that was metallurgical bonded to the matrix. The bonding strength, hardness and wear properties of the cladding layers were enhanced while porosity was reduced. Grain abrasion of WC was the main mechanism of the WC-Co coating found by wear tests.