The grain size-dependent electrical properties of Bi4Ti3O12 piezoelectric ceramics

Abstract

Due to the poor insulating property of the pure bismuth titanate Bi4Ti3O12 (BIT) ceramic, it is very difficult to obtain the piezoelectric properties. This study focuses on the effect of the grain size on the electric properties and thermal stability of BIT ceramics. The BIT ceramic with different grain sizes from 4.2μm to 0.28μm were prepared by three sintering methods: normal sintering, two-step sintering and hot pressing sintering. Result shows that the problem of large leakage current of BIT ceramics can be solved by reducing grain size. The piezoelectric properties of BIT ceramics have a strong dependence on the grain size since two factors of internal stress and poling electric field strength both influences the degree of ferroelectric domain switching. The thermal stability is decreased with decreasing of the grain size since internal stresses provide an additional driving force that assists the thermal depolarization.