Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd ₂ SiO ₅ for environmental barrier coatings

The Gd 2 SiO 5 performed high‐temperature corrosion behavior on calcium–magnesium– aluminosilicate (CMAS) for environmental barrier coatings (EBCs). The synthesized Gd 2 O 3 ‐SiO 2 powder was prepared to fabricate a sintered Gd 2 SiO 5 by spark plasma sintering (SPS) at 1400°C for 20 min. CMAS was sprinkled on the sintered Gd 2 SiO 5 surface and exposed for 2, 12, and 48 h at 1400°C by isothermal heat treatment. The main corrosion factor is Ca, and Ca 2 Gd 8 (SiO 4 ) 6 O 2 phase is formed by reacting with Gd 2 SiO 5 . Extended morphology of Ca 2 Gd 8 (SiO 4 ) 6 O 2 particles observed in the reaction area become thicker as the heat treatment time increases as the CMAS is dissolved. According to the results of high‐temperature X‐ray diffraction (HT‐XRD) and differential scanning calorimetry (DSC), CMAS melted at 1243°C or a higher temperature formed the reaction area. The Ca 2 Gd 8 (SiO 4 ) 6 O 2 phase was recrystallized and grown due to the reaction of Gd 2 SiO 5 and Ca of the CMAS components.