Effects of laser glazing on CMAS corrosion behavior of Y2O3 stabilized ZrO2 thermal barrier coatings

Calcium-magnesium-alumina-silicate (CMAS) is a serious threat to thermal barrier coatings (TBCs). The goal of this study is to tailor YSZ coating microstructures by laser for alleviating CMAS attack. A smooth laser glazed layer with a columnar microstructure and some open channels is produced on the coating surface. Under molten CMAS conditions, the glazed layer remains phase stability and has little evidence of dissolution. Exposed to thermal shock tests with CMAS deposits, the glazed layer keeps structural integrity. However, the open channels also act as the paths for CMAS penetration, which brings destructive damages to the coating beneath the glazed layer.