Composition-Driven Phase Transition and Electrical Perfor-mances of 0.74BiFe1-xGaxO3-0.26BaTiO3 High Temperature Lead-Free Piezoceramics [0.74BiFe1-xGaxO3-0.26BaTiO3 高温无铅压电陶瓷的相变行为及电性能]

作者：Yi W.; Lu Z.^*; Liu X.; Huang D.; Jia Z.; Chen Z.; Wang X.; Zhu H.

来源：Rare Metal Materials and Engineering, 2022, 51(2): 374-377.

• BiFeO3-BaTiO3
• Electrical performances
• Lead-free
• Phase transition
• Piezoelectric materials

Morphotropic phase boundary (MPB) is very important for enhancing piezoelectric properties of piezoceramics. In general, the MPB of BiFeO3-BaTiO3 system ceramics locates near the composition of 0.70BiFeO3-0.30BaTiO3. However, higher content of BaTiO3 will lead to lower Curie temperature of BiFeO3-BaTiO3 ceramics. Therefore, constructing an MPB for BiFeO3-BaTiO3 ceramics with lower BaTiO3 content is a reasonable strategy to obtain both the good piezoelectric property and high Curie temperature. 0.74BiFe1-xGaxO3-0.26BaTiO3 (x=0~0.05) lead-free piezoceramics were fabricated by traditional sintering methods, and effect of Ga content on the structures and electrical performances was investigated. Results show that a composition-driven phase transition from rhombohedral (R) to pseudocubic (pC) is identified as x increases from 0 to 0.05. The ceramics show symmetries of R at x≤0.01 and pC at 0.04≤x≤0.05, and the MPB with R-pC coexistence is detected in the composition range of 0.02≤x≤0.03. The Curie temperature of the piezoceramics decreases slightly owing to increased tolerance factor t with the increment of Ga content. In particular, the high Curie temperature ~515 °C and improved piezoelectric property of piezoelectric coefficient d33 of ~127 pC/N are obtained in the ceramics near MPB.

• 单位
  华南理工大学