Effect of Zr~(4+) substitution on thermal stability and electrical properties of high temperature BiFe_(0.99)Al_(0.o1)O_3-BaTi_(1_x)Zr_xO_3 ceramics

摘要

High-temperature Pb-free ceramics of 0.72BiFeo.99Al_(o.o1)O_3-0.28BaTi_(1-x)Zr_xO_3 (BFA-BZ_XT) have been prepared through solid state reaction route. The influence of the Zr~(4+) substitution forTi~(4+) on microstructure, thermal stability and electrical properties of the BFA-BZ_xT ceramics was investigated. The results showed single-phase solid solutions occurred for compositions x = 0-0.12 and a morphotropic phase boundary (MPB) separating rhombohedral and pseudocubic phases existed near x = 0.03. The substitution of Zr~(4+) for Ti~(4+) caused significant change of grain size for BFA-BZxT ceramics. The optimum piezoelectric properties of d33 = 157pC/N, k_p = 0.33, combined with improved depoling temperature T_d = 425°C, are obtained around the MPB composition of x = 0.03. The results indicate that BFA-BZ_XT ceramics have a great potential to apply in high temperature field.