Prism-plane-textured Cr2AlC MAX-phase coatings with superior resistance to coupled thermal–salt–steam corrosion

Abstract

Conventional protective coatings tend to fail prematurely under the extreme thermal–salt–steam coupled conditions typical of marine and aero-engine operating environments. Here, we present a strategy to enhance corrosion resistance by fabricating Cr₂AlC MAX-phase coatings with a strong (11$\overline{2}$0) prism plane texture, achieved via synchronized pulsed HiPIMS deposition. As a control, a texture-free, equiaxed Cr₂AlC coating was also prepared. Following a 5 h exposure to a simulated thermal–salt–steam environment at 600 °C, the textured coating demonstrated exceptional corrosion resistance, forming a corrosion scale that was only one-third the thickness of its equiaxed counterpart. Mechanistic investigations revealed that the Prism-plane coating orientation accelerates the formation of a dense, uniform amorphous Al₂O₃ scale, which acts as an effective barrier against corrosive species. These findings underscore the pivotal role of crystallographic orientation in environmental durability, offering a pathway to design high-performance MAX-phase coatings for extreme service conditions.