Bi compensation and poling process to enhance piezoelectric properties of BiFeO3-BaTiO3 lead-free piezoceramics

BiFeO 3 -BaTiO 3 (BF-BT) ceramics are an excellent choice for high-temperature lead-free piezoelectric ceramic due to their high Curie temperature and good piezoelectric properties , but the volatilization of Bi leads to the formation of A-site cationic vacancies and oxygen vacancies , culminating in heightened leakage currents and detrimental effects on piezoelectric properties. In this study, a chemical composition of 0.70Bi (1+ x ) Fe 0·97 Al 0·03 O 3 -0.30BaTiO 3 ceramics, abbreviated as B 1+ x FA-BT, where 0 ≤  x  ≤ 0.05, were synthesized, with special attention on the effects of Bi compensation and poling process on their insulation and piezoelectric properties. Due to the coexistence of R - PC phases and low leakage current, B 1+ x FA-BT ceramics exhibit excellent piezoelectric properties and high Curie temperature, among which the B 1.02 FA-BT ceramic boasts optimal overall properties: d 33  = 196 pC N −1 , T C  = 480 °C, k p  = 34%, θ max  = 49.5° and Q m  = 32, under optimal poling parameters E p  = 50 kV cm −1 and T p  = 100 °C. The poling process is directly linked to the reorientation of domains, the redistribution of positive/negative space charge and the aggregation or injection of holes, which is achieved by tuning the poling field and temperature in a ceramic with optimal integrated piezoelectric properties. The poling process of BF-BT ceramics is significantly influenced by their leakage characteristics, which can have a significant impact on their overall performance. Optimizing electrical poling conditions and minimizing leakage current is crucial to achieving favorable piezoelectric properties in BF-BT ceramics with R - PC coexisting structures.