Effect of Al2O3 and Ta2O5 on Mechanical and Electrical Properties of Ti4O7 Ceramics

Ti ₄ O ₇ is one of the most promising electrically functional materials among the Magnéli phase. To further broaden its applications in areas such as battery electrodes and pollutant treatment, extensive research has been conducted to optimize its mechanical and electrical properties. In this study, Ti ₄ O ₇ ceramics, as well as Al ₂ O ₃ and Ta ₂ O ₅ ‐doped Ti ₄ O ₇ ceramics, are fabricated via hot‐press sintering using a solid‐state method. While the introduction of secondary phases did not result in a significant improvement in the mechanical properties of Ti ₄ O ₇ ceramics, the effectiveness of Al–Ta co‐doping in enhancing electrical conductivity is validated through three commonly used measurement techniques: the Van der Pauw method, the two‐probe method, and the four‐probe method, yielding conductivity increases of 46.20, 1.98, and 17.98%, respectively. Detailed electrical characterization further elucidated the electrical features of polycrystalline Ti ₄ O ₇ ceramics and effect of doping. Furthermore, the reaction between Ti ₄ O ₇ and Ta ₂ O ₅ , leading to the formation of the ternary oxide TiTaO ₄ , is observed.