Effects of processing parameter on phase transition and electrical properties of lead-free BNKT piezoelectric ceramics

ABSTRACT

Lead-free piezoelectric ceramics of Bi_0.5(Na_0.80K_0.20)_0.5TiO₃ powders were prepared via a conventional solid-state reaction method, and effects of calcination temperature on many properties of the ceramics were investigated. XRD patterns for all ceramic samples showed coexistence between rhombohedral and tetragonal phases without any impurity. Calcination temperatures from 700 to 1000°C shifted depolarization temperature from 92 to 100°C. Dielectric and piezoelectric properties were improved and showed the optimum values for the ceramics which calcined at 800°C. The improvements of piezoelectric properties were related with the ceramic densification and MPB composition.

KEYWORDS:

• Phase transition
• BNKT
• piezoelectric properties
• calcination temperature

Funding

This work was supported by the National Research University Project under Thailand's Office of the Higher Education Commission, The National Research Council of Thailand, The Thailand Research Fund (BRG 6080002, IRG5780013), CMU 50th anniversary Ph.D. Grant from Chiang Mai University (PHD/011/2557), Department of Physics and Materials Science, Faculty of Science and Graduate School, Chiang Mai University. Science and Technology Research Institute, Chiang Mai University, Thailand is also acknowledged.