High-temperature oxidation behavior of dense polycrystalline Ti4O7 ceramics in air

While the high-temperature oxidation behavior of ceramics has attracted widespread attention, the oxidation behavior of suboxide ceramics is rarely studied, which is essential for promoting broader application of suboxide ceramics. Herein, the high-temperature oxidation behavior of dense polycrystalline Ti 4 O 7 ceramics was investigated in air at 600–1000 °C (873–1273 K). The results reveal that oxidation has a significant impact on the phase composition, microstructure, and mechanical and electrical properties of ceramics. Notably, oxidation at 800 °C for 3 h leads to more than a 60 % increase in flexural strength. The oxidation of Ti 4 O 7 ceramics follows a parabolic law, with a calculated apparent activation energy of 235.60 kJ/mol. Validation experiments involving the introduction of Ta 2 O 5 second phase further support the proposed oxidation mechanism, which is governed by the outward diffusion of interstitial titanium. This study provides both a reference for understanding the oxidation behavior and resistance of titanium suboxide ceramics and new insights into mass transport mechanisms in similar materials.