(Bi1/2K1/2)TiO3 lead-free ferroelectric ceramics: processing, properties, and compositional modifications

Bismuth potassium titanate (Bi1/2K1/2)TiO3 with an A-site complex perovskite structure is regarded as a promising lead-free ferroelectric/piezoelectric material. Studies on the fundamental properties of (Bi1/2K1/2)TiO3 have, however, been faced with difficulties in fabricating dense and phase-pure (i.e., high-quality) bulk ceramics caused by its low melting point and the volatility of Bi and K. This paper reviews our findings on the fabrication process and fundamental properties of such high-quality (Bi1/2K1/2)TiO3 ceramics. After a brief survey on the crystal structure and physical/chemical stability of (Bi1/2K1/2)TiO3 , our fabrication process of (Bi1/2K1/2)TiO3 ceramics utilizing the hydrothermal synthesis method is described. Then, the phase transition behavior of (Bi1/2K1/2)TiO3 is discussed based on the electrical and electromechanical responses of the high-quality ceramic samples. The last part of this paper presents two examples of compositional modifications of (Bi1/2K1/2)TiO3 ceramics aiming at developing dielectric and piezoelectric materials for use in capacitors and actuators. (C) 2021 The Ceramic Society of Japan. All rights reserved.

Automated summary

This paper reviews the fabrication process and fundamental properties of high-quality (Bi1/2K1/2)TiO3 ceramics, including crystal structure, physical/chemical stability, phase transition behavior, and compositional modifications for dielectric and piezoelectric materials. The hydrothermal synthesis method is utilized for the fabrication of (Bi1/2K1/2)TiO3 ceramics, and the electrical and electromechanical responses of the ceramic samples are discussed for potential applications in capacitors and actuators.