Influence of thermal shock behavior on microstructure and interface bonding strength of WC/W coating

Abstract In this work, Tungsten carbide (WC)/tungsten (W) coating samples were successfully fabricated by in-situ synthesis method. The thermal shock behavior of the samples were evaluated by rising the samples to 500 °C, 800 °C and 1000 °C, keeping 10 min, and then cooling to room temperature under hydrogen protection. It was found that the coating present excellent thermal shock resistance at 500 °C, with only hairline cracks generated, while the coating began to peel off from the substrate after thermal shock at 1000 °C for 50 cycles. The mechanism of crack propagation during the thermal shock process was also discussed. The interface bonding strength of coating/substrate was tested by scratching method, and the results showed that the interface bonding strength decreased dramatically after thermal shock at 1000 °C for 50 cycles, and the interface bonding strength decreased by 50.8% after 50 cycles thermal shock.