High-temperature interaction of nanostructured Lu2Si2O7 environmental barrier coatings with CMAS melts at 1400°C

The high-temperature interaction of nanostructured Lu 2 Si 2 O 7 environmental barrier coatings (EBCs) with calcium–magnesium–aluminosilicate (CMAS) was investigated at 1400°C for 1, 10, 25, and 50 h to evaluate the coating’s resistance to CMAS corrosion. The results indicate a phase transformation over time, transitioning from Ca 2 Lu 8 (SiO 4 ) 6 O 2 apatite and Lu 2 Si 2 O 7 to solely Lu 2 Si 2 O 7 . The interaction of the Lu 2 Si 2 O 7 coating with the CMAS melts was divided into three stages based on the corrosion reaction behavior. The delamination cracks were distributed throughout the interface between the Si bond layer and Lu 2 Si 2 O 7 layer after corroded at 1400°C for 50 h, signifying coating failure. In addition, the influence of monosilicates, disilicates, and corrosion duration on the recession layer thickness was analyzed by comparing previous reports on RE 2 SiO 5 /RE 2 Si 2 O 7 coatings (RE = Gd, Yb, Lu, Er). Furthermore, the variation in the thermally grown oxide layer thickness in CMAS-corroded Lu 2 Si 2 O 7 coatings was systematically investigated.