S. Zhou, C. Shen, H. Li, Y. Zhang, D. Estrella, A. Sanjuan, D. Hermawan, B. Tsai, J. Huang, X. Sheng, A. Choudhury, Y. Chen, R. E. García, X. Zhang, Haiyan Wang “Phase-Boundary Assisted Flash Sintering of Al₂O₃-TiO₂ Nanocomposites.” Acta Materialia. 302:121612, 2026. https://doi.org/10.1016/j.actamat.2025.121612

Abstract

Al₂O₃ is inherently challenging to flash sinter due to its highly insulating nature. In contrast, TiO₂ can be flash sintered readily due to its better electrical and ionic conductivity at elevated temperatures than those of Al₂O₃. In this study, two-phase composites of Al₂O₃-TiO₂ with various molar ratios (i.e., 34 mol.% Al₂O₃/66 mol.% TiO₂ and 20 mol.% Al₂O₃/80 mol.% TiO₂) have been successfully processed by flash sintering and a systematic flash sintering map has been constructed to explore the relationship between electric field (ranging from 300 to 1600 V/cm) and the flash sintering temperature in Al₂O₃-TiO₂ composites. The map clearly demonstrates that the flash sintering temperature of composites decreases with increasing electric field or higher TiO₂ molar ratio. The potential mechanisms of phase boundary assisted flash sintering are discussed. This study confirms that the appropriate design of two-phase composites can prominently promote the flash sintering of insulating ceramic materials.