Atomic Scale Insight into the Oxidation Mechanism of Nb/Ta‐Doped Ti₃SiC₂/Al₂O₃ Ceramics

Abstract

The low oxidation resistance of Ti3SiC2/Al2O3 composites limits their applications as high‐temperature structural materials. To improve the oxidation resistance, Nb and Ta were introduced into the substrate in this study. The Nb/Ta‐doped Ti3SiC2/Al2O3 composite showed superior oxidation resistance than clean Ti3SiC2/Al2O3 following the oxidation process at 800–1000 °C for 100 h. The oxidation mechanism was determined via first‐principles calculations. The oxidation process of the composite was controlled by the inward diffusion of O and outward diffusion of Ti. When Nb/Ta elements are doped, their larger atomic radii and stronger binding produce a higher diffusion barrier for O and Ti atoms, which prevents element migration and reduces the thickness of the oxidation layers.This article is protected by copyright. All rights reserved.