Superior high-temperature wear resistance in ceramic-based coatings via laser remelting-induced microstructural modification

In advanced aero-engine applications, designing high-temperature self-lubricating coatings with low friction and excellent wear resistance is crucial for the durability of turbine components. In this work, a YSZ-based ceramic composite coating was deposited on a C/SiC ceramic matrix composite by supersonic atmospheric plasma spraying (SAPS) and modified by laser remelting (LR). The LR transformed the lamellar structure into a dense dendritic architecture, eliminating pores and interlamellar defects, and enhancing mechanical integrity. Tribological tests at 800 °C demonstrated that increasing remelting energy density significantly improved wear resistance and slightly reduced the coefficient of friction (COF). The MA-P600 coating exhibited a wear rate of 7.80 × 10⁻⁸ mm³/N·m, two orders of magnitude lower than that of the unremelted coating, while maintaining a low COF of 0.28. Microstructural analysis reveals that LR and friction induce a layered structure consisting of an ultrathin third body layer (TBL) and an underlying stress-affected zone (SAZ). The TBL, composed of fine CaMoO₄ and Ag grains, provides thermal stability and lubrication. The SAZ, rich in c-ZrO₂ and CaF₂, offers load support and crack resistance. The synergy between soft and hard phases enables excellent tribological performance under extreme conditions. This work presents an effective strategy for enhancing the wear resistance of plasma-sprayed ceramic-based coatings through LR, providing guidance for designing self-lubricating coatings for aerospace and other extreme environments.