Effect of interface roughness on the CMAS + molten salt (Na2SO4 + NaCl + NaVO3) corrosion resistance of EB-PVD thermal barrier coatings

The service life of thermal barrier coatings (TBCs) in calcium magnesium aluminosilicate (CMAS) and molten salt environments has become a key factor in determining engine reliability and safety. The effect of interface roughness (bond coating surface roughness) on the CM (CMAS + molten salt (Na 2 SO 4  + NaCl + NaVO 3 )) corrosion resistance of electron beam physical vapor deposition (EB-PVD) TBCs is investigated. The addition of molten salts lowers the melting point of CM, leading to more severe destructive effects compared to single CMAS corrosion. Moreover, the 1200# specimen (Ra = 2.0 μm) exhibits the best resistance to CM corrosion. The adjustment of interface roughness significantly alters the microstructure of the top-ceramic coating and induces changes in crack patterns after CM corrosion. Therefore, appropriately reducing interface roughness is key to improving the isothermal CM corrosion resistance and high-temperature CM corrosion-induced thermal shock performance of TBCs.