Laser ablation behavior and ablation threshold of entropy-controlled perovskite coatings

The protection threshold of laser ablation resistant materials lags behind the development of laser power density. Single-functional laser ablation resistant materials can no longer meet the practical needs. High-entropy perovskites with infinite chemical composition, tunable bandgap structure, and efficient thermal management capabilities provide new ideas for developing novel high-reflectivity and low-thermal-conductivity multifunctional laser ablation resistant materials. Herein, leveraging these unique advantages of high-entropy perovskites in optics and thermodynamics, four entropy-controlled perovskite coatings, Ba(Zn1/2Ta1/2)O3 (BZTO), Ba(Zn1/3Ta1/3Nb1/3)O3 (BZTNO), Ba(Zn1/4Ta1/4Nb1/4Ti1/4)O3 (BZTNTO) and Ba(Zn1/5Ta1/5Nb1/5Ti1/5Zr1/5)O3 (BZTNTZO) are designed. Through time-dependent laser ablation experiments, the optical and thermal properties are comprehensively evaluated. And laser ablation behavior and ablation threshold are systematically studied. The BZTNO achieves thermal equilibrium at 1000 W∙cm‒2 and possesses longest ablation thresholds at different energy densities, demonstrates a superior thermal management performance. The optical reflectivity and the thermal expansion coefficient matching with the steel substrate make a major contribution to the excellent laser ablation resistant performance. The ablation thresholds of other entropy-controlled samples increase with entropy. This is attributed to the fact that the increase of cation disorder can effectively reduce the thermal conductivity. The designed entropy-controlled perovskite systems offer wide application prospect in laser ablation.