Enhancing the electrical properties of high-Curie temperature BNT–PZT piezoceramics by oxides-hydrothermal method

Abstract

The difference between the oxides-hydrothermal (O-HT) method and the traditional hydrothermal method is that the former uses insoluble or poorly soluble metal oxides as raw materials. The O-HT method is mainly used to study the luminescence properties of rare-earth nanomaterials. In this work, the O-HT method has been used for the synthesis of high-Curie temperature (high-TC) 0.3Bi(Ni1/2Ti1/2)O3–0.7Pb(Zr0.52Ti0.48)O3 (0.3BNT–0.7PZT) piezoelectric ceramic powders at different hydrothermal synthesis temperatures. After the O-HT synthesis, ceramic powders are calcined and sintered. The effects of different hydrothermal synthesis temperatures on the crystallinity, structure, morphology, and electrical performance of the products are investigated. At a low hydrothermal synthesis temperature of 200 °C for 12 h, well-crystallized ceramic powders are obtained. After sintering, the ceramic samples exhibit a dense microstructure and optimal electrical properties (εr = 6840, d33 = 501 pC/N, TC = 245 °C, Pr = 14.79 μC/cm2, and Ec = 16.86 kV/cm). The experimental results show that applying O-HT technology can dramatically induce grain growth during sintering and improve the piezoelectricity and Curie temperature of samples and that it has the advantages of energy saving, environmental recycling, and suitability for industrial mass production.