The Study On Piezoelectric Properties Of BaTiO₃based Lead-free Piezoelectric Ceramics

BaTiO₃is one of the most important electronic ceramics material. Bariumtitanate-based ceramics has been widely used in industrial electronic products becauseof its excellent dielectric and piezoelectric properties.Lead zirconate titanate （PZT） has been dominant in the development andapplication of piezoelectric ceramics for a long time. PZT-based ceramics is a seriousenvironmental pollution material. Therefore looking for lead-free piezoelectricmaterials that can replace PZT becomes one of the urgent task in the field ofelectronic materials. As a potential material, barium titanate-based lead-freepiezoelectric ceramic comes back to our attention. The Curie temperature of bariumtitanate is120°C, that limit the application of barium titanate-based ceramics greatly.Improving its performance has become an important issue at present. Dopingmodification is currently the most widely used method to improve its performance.This paper aims to seek a research plan which can promote the Curie temperature ofbarium titanate significantly and keep good piezoelectric properties at the same time.Bi and Cu co-doped BaTiO3ceramics were prepared through solid-state reactionand liquid method respectively. This paper investigated the influence of the amount ofdoping and the sintering temperatures on microstructure, morphology, Curietemperature and piezoelectric properties of （Ba1-2xBi2x）（CuxTi1-x）O3ceramic. Theprocess conditions has been analyzed to prepare （Ba0.99Bi0.01）（Cu0.005Ti0.995）O3powderby sol-gel self-ignition method. The effects of different sintering temperatures on themicrostructure, phase, dielectric and piezoelectric properties of(Ba_0.99Bi_0.01)(Cu_0.005Ti_0.995)O₃ceramics was investigated. The results demonstrate thatCu and Bi co-doping promotes the Tc from120℃to155℃and reduces sinteringtemperature. Samples sintered at1240℃show the optimum piezoelectric properties,and its piezoelectric constant d33, electromechanical coupling factor Kp, mechanicalquality factor Qm, and piezoelectric constant d31reach80pC/N,12.6%,310and-16.8pC/N, respectively. And the piezoelectric temperature stability has been greatlyimproved.