The Effect of Sintering Atmosphere and Temperature on Densification, Grain Growth Behavior and Electrical Properties of 0.685(Na0.5Bi0.5)TiO3-0.065BaTiO3-0.25SrTiO3 Ceramics

Abstract

(Na0.5Bi0.5)TiO3-BaTiO3-SrTiO3-based lead-free piezoelectric ceramics are one of the possible replacements for Pb(Zr1-xTix)O-3. Although they are considered a promising alternative actuator material due to their large electric-field-induced strains, they have several drawbacks, such as large strain hysteresis and the requirement of a high electric field to obtain large electric-field-induced strains. Sintering parameters strongly influence the electrical properties. Thus, the effect of sintering parameters, including atmosphere (air/oxygen), temperature (1150 degrees C similar to 1250 degrees C) and holding time (1 similar to 20 h) on the sintering behavior of 0.685(Na0.5Bi0.5)TiO3-0.065BaTiO(3)-0.25SrTiO(3) electroceramics was studied. Then, the influence of sintering atmosphere on the piezoelectric, ferroelectric and dielectric properties of 0.685(Na0.5Bi0.5)TiO3-0.065BaTiO(3)-0.25SrTiO(3) electroceramics sintered at 1250 degrees C for 1 h was investigated. Sintering in oxygen improves density and restrains grain growth including abnormal grain growth. 0.685(Na0.5Bi0.5)TiO3-0.065BaTiO(3)-0.25SrTiO(3) electroceramics sintered in oxygen exhibit smaller grain size, higher density, similar inverse piezoelectric coefficient d(33)* and lower strain hysteresis compared to air-sintered samples. The effect of sintering atmosphere on grain growth is explained using the mixed control mechanism of boundary migration.