Improving Electrical Properties in Lead-Free BNT Based Ceramics by BLT Doping

Abstract

(1-x)Bi_0.5Na_0.5TiO₃-x(Bi_3.25La_0.75)Ti₃O₁₂; (1-x)BNT-xBLT ceramics with x = 0–0.20 wt.% were prepared by solid-state reaction method. The Bi_0.5Na_0.5TiO₃ (BNT) and (Bi_3.25La_0.75)Ti₃O₁₂ (BLT) powders were calcined separately. The BNT powder was calcined at 850 °C for 2 h. and BLT powder at 750 °C for 4 h. The (1-x)BNT-xBLT samples were sintered between 1050 °C and 1200 °C for 4 h. All samples exhibit almost a pure perovskite phase with coexistence of rhombohedral and orthorhombic phases. The average grain size decreased with increased in x(BLT) contents. The maximum density and relative density of about 5.87 ± 0.11 g/cm³ and 97.2% were obtained for the composition of 0.97BNT–0.03BLT. The temperature at maximum permittivity (T_m) tended to increase from 324 °C to 341 °C with increase in x(BLT) contents. The results revealed that the fatigue behavior was improved in the sample of 0.97BNT–0.03BLT, where a slight decrease in remanent polarization with low degradation of ferroelectric properties was observed after electrical fatigue.

KEYWORDS:

• BNT-BLT
• fatigue behaviors
• ferroelectric properties
• dielectric properties
• phase structure

Acknowledgments

The authors wish to thank the Faculty of Science and Technology, Pibulsongkram Rajabhat University is also supported. Thanks are given to Dr. Nitish Kumar for his help in editing the manuscript.

Funding

This work financially supported by the National Research Council of Thailand (NRCT) through Pibulsongkram Rajabhat University (grant no. RDI-1-61-6-15).