Boosting corrosion resistance of environmental barrier coatings through surface aluminum modification against molten salts

Aluminum modification of Yb₂Si₂O₇(YbDS)/Si EBC coating was proposed to improve CMAS corrosion resistance. After modification, a continuous Yb₃Al₅O₁₂ (YbAG) layer formed in situ on the surface of the YbDS topcoat. Coatings were exposed to CMAS at 1300 ℃ and 1400 ℃ for 5 h and 25 h respectively to study their resistance. YbDS reacted with the melt to form silicate garnet, and higher temperatures caused complete YbDS dissolution.The modified coating remained intact, reducing recession thickness by 90 %. This is primarily due to the non-reactive YbAG layer and its continuous structure, protecting YbDS from direct interaction with the melt.