Interface protection mechanism of Ti₃AlC₂ ceramics under CMAS corrosion condition

Abstract The interface protection mechanism of Ti₃AlC₂ ceramics against calcium–magnesium–aluminum–silicate (CMAS) corrosion and change in physical properties were investigated. At 1200°C, CMAS components melted and rapidly reacted with ceramic at the interface, penetrating the interior. Concurrently, due to the high‐temperature oxidation, a dense oxide layer was formed on the Ti₃AlC₂ surface, effectively blocking the CMAS and generating Ti m Ca x Si y O 2 m + x + 2 y and Al 2n Ca x Si y O 3n + x + 2 y . Quantitative analysis using energy‐dispersive spectroscopy (EDS) revealed that after 15 h of corrosion, the maximum penetration depth of CMAS was 0.9 µm, with silicon and calcium identified as predominant elements. Benefiting from the protective oxide layer at the interface, the thermal expansion coefficient (CTE) of corroded Ti₃AlC₂ was 9.01 × 10 6 K −1 , which closely matching that of intact Ti 3 AlC 2 , and the thermal diffusivity at 25°C and 1200°C were 0.1253 mm −2 ·S −1 and 0.0693 mm −2 ·S −1 , with retention rates of 79.7% and 88.5%, respectively.