Corrosion behavior of calcium–magnesium–aluminosilicate (CMAS) on sintered Gd2SiO5 for environmental barrier coatings

The Gd2SiO5 performed high‐temperature corrosion behavior on calcium–magnesium– aluminosilicate (CMAS) for environmental barrier coatings (EBCs). The synthesized Gd2O3‐SiO2 powder was prepared to fabricate a sintered Gd2SiO5 by spark plasma sintering (SPS) at 1400°C for 20 min. CMAS was sprinkled on the sintered Gd2SiO5 surface and exposed for 2, 12, and 48 h at 1400°C by isothermal heat treatment. The main corrosion factor is Ca, and Ca2Gd8(SiO4)6O2 phase is formed by reacting with Gd2SiO5. Extended morphology of Ca2Gd8(SiO4)6O2 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 Ca2Gd8(SiO4)6O2 phase was recrystallized and grown due to the reaction of Gd2SiO5 and Ca of the CMAS components.