Role of thermal gradients on the depolarization and conductivity in quenched Na1/2Bi1/2TiO3-BaTiO3

Abstract

Quenching has been demonstrated to increase the thermal stability of the piezoelectric properties of relaxor (1-x)Na1/2Bi1/2TiO3-xBaTiO3 (NBTxBT) by 40 °C. This work establishes a correlation between the quenching temperature and salient electrical (conductivity, piezoelectric and dielectric) properties of two NBTxBT variants. The impact of quenching on the mechanical properties is quantified in terms of changes in Young's modulus. The perspective for application is interrogated using a variation in the sample thickness and separating the sample interior from the sample surface. An in situ measurement of surface temperature during the quenching treatment is applied to validate the simulation for thickness-dependent thermal transport in the material and ensuing transient thermal stresses. The calculated stress intensity factor is then compared with the fracture toughness of the material. This study asserts that air quenching can be conducted without mechanical degradation. Thus, it can be an important alternative to existing industrial strategies to enhance the thermal stability of the piezoelectric properties of relaxor NBTxBT.