Yb2SiO5-Yb2Si2O7 gradient environment barrier coating ： rational design and corrosion behavior in water vapor environment at 1300 ℃

Gradient environmental barrier coatings (EBCs) were fabricated via atmospheric plasma spraying to deposit Yb2Si2O7-Yb2SiO5 onto a laser-sculpted SiC substrate, with varying mass ratios. Experimental results reveal that the gradient coating exhibited remarkable integrity, showing no signs of cracking even after exposure to 90% H2O-10% O2 (g) water vapor corrosion at 1300 ℃ for 100h. Besides, the thickness of the thermally grown oxide (TGO) layer was minimal (18.53 ± 1.08 μm) compared to 75Yb2Si2O7-25Yb2SiO5 single layer EBCs (24.93 ± 1.62 μm) with similar integrity under water vapor environment for 100h. The superior performance of the gradient coating against water vapor corrosion can be attributed to the outmost layer containing more Yb2SiO5 with excellent vapor corrosion resistance, while the innermost layer primarily comprises Yb2Si2O7, providing significant damage resistance and resilience to thermal shock. These favorable attributes make the gradient coating a promising candidate for EBC application in aerospace.