Ablation behavior of SiC whisker and ZrB2 particle-filled ZrO2 sol-gel composite coating under high-intensity continuous laser irradiation.

In this study, laser ablation-resistant composite coating consisting of zirconium diboride (ZrB 2) particulate and silicon carbide (SiC) whisker with zirconia (ZrO 2)-sol binder was prepared to meet requirements of anti-laser ablation ability. Laser ablation behavior of as-prepared coating was investigated under varying laser powers. Results revealed that the highest back-surface temperature of coated aluminum substrate was only 150 °C when irradiated at a power density of 6.3 kW/cm2 for 10 s, which is below the maximum allowable temperature of the aluminum alloy substrate (200 °C). After ablation for 10 s, the mass ablation rate of the composite coating was 4.45 mg/s. Apparently, the composite coating exhibited outstanding ablation resistance against high-intensity continuous laser irradiation. At initial stage of ablation, combination of self-healing effect of liquid ZrO 2 –SiO 2 layer and volatilization of B 2 O 3 provide effective joint protecting mechanism. With increasing ablation time, ZrO 2 ceramic barrier layer, product of the pyrolysis of ZrO 2 gel and ZrB 2 filler, becomes progressively more important in maintaining excellent laser ablation resistance behavior, which is normally effective at around ablation pit. [ABSTRACT FROM AUTHOR]