Effect of high entropy on the corrosion resistance of environmental barrier coatings: Evolution of pore structure, transport mechanisms and corrosion behavior

Abstract

Water vapor-induced corrosion leading to microstructural degradation remains a critical failure mechanism for environmental barrier coatings (EBCs). Two types of SiC/Si/(Yb_0.2Y_0.2Lu_0.2Er_0.2Sc_0.2)₂Si₂O₇ and SiC/Si/Yb₂Si₂O₇ prepared by atmospheric plasma spraying were investigated, with an emphasis on the evolution of pore structure, transport mechanisms, and corrosion behaviors at 1400°C in this study. The results show that high-temperature water vapor corrosion involves molecular diffusion dominated by macroporous pores and Knudsen diffusion dominated by microporous pores, where submicron pores slow down the penetration of corrosive gases. Meanwhile, The high-entropy coating exhibited enhanced stability due to increased bond energy and lattice distortion, which suppressed pore expansion and extended service life. Phase transitions and pore dynamics analysis demonstrates that optimized pore architecture mitigates gas transport, while entropy-driven chemical modifications improve structural integrity, which is essential for the design of durable EBCs.