The impact of TiO2 crystal phase and size on properties of ultra-high Curie temperature La2Ti2O7 ceramics

The study conducts an in-depth analysis of the role of the crystal phase and particle size of TiO 2 in the preparation of La 2 Ti 2 O 7 (LTO) ceramics via the conventional solid-state method. Comparative studies on crystal structure, micromorphology, electrical properties and mechanical properties were performed, revealing that the selection of TiO 2 raw materials greatly influences the structure and performance of LTO ceramics, resulting in significant differences in the grain sizes, electrical properties, and mechanical properties of the ceramics. Among the various TiO 2 sources, the LTO ceramics synthesized with nano-rutile TiO 2 exhibit superior overall performance. The smaller grain size of 1.43 nm for the ceramic and higher relative density of 98.27 %, significantly enhance their electrical and mechanical properties. The piezoelectric constant is 1.5 pC/N at room temperature and 1.4 pC/N after annealing at 1000 °C for 48 h. The high Curie temperature with 1450 °C, high resistivity with 3.93 × 10 6  Ω cm at 600 °C, high hardness of 9.89 GPa and small change in elastic modulus make it excellent candidates for high-temperature electronic component applications.