Microstructures and adhesion of the oxide scale formed on titanium aluminum carbide substrates

Abstract

Microstructures of oxidized Ti 3AIC 2 and Ti 2AlC were investigated using transmission electron microscopy. The presence of Ti-rich precipitates in the A1 2O 3 oxide scale and the enrichment of Ti in the Al 2O 3 grain boundaries were identified. High diffusivity of Al in the carbides contributes to the selective oxidation of AI. Moreover, the adhesive strength between the oxide scales and the substrates exceeds 85 MPa. Strong adhesive strength contributes to the thermal-cyclic stability of the oxide scales. © 2006 The American Ceramic Society.