Novel magnetron sputtered ceramic YSiFe oxide as CMAS-resistant coatings for environmental barrier coatings.

Abstract

A novel YSiFe oxide coating has been developed and a suitable heat-treatment was applied to achieve the crystalline phases that are stable at high temperatures. The heat-treatment includes an isothermal heating at 1250 °C for 1h followed by a rapid cooling to room temperature. The resultant phases: X2-Yttria Mono Silicate (YMS), Yttrium Iron oxide and Yttria were found to be nano-crystalline in nature and were homogeneously distributed in the coating. The coating has been subjected to CMAS reaction by performing infiltration experiments at 1300 °C for different time intervals. It was found out that the studied YSiFe oxide coating has induced the both the intrinsic crystallisation of the CMAS melt and formed reaction products such as oxyapatite and garnet phases. The Fe diffusion from the YSiFe oxide coating into the glass reinforced the reactive crystallisation of CMAS leading to apatite and further garnet formation which consumed CMAS glass and prevented further infiltration. This novel coating has been proven to be a very good CMAS resistant coating and could therefore be a promising candidate for CMAS resistant multilayer EBCs.