Research On The Piezoelectric And Dielectric Storage Properties Of Lead-free Piezoelectric Ceramics

Material as an important basis and effective protection for the information industrial andsocio-economic development, with energy and information are called the three pillars of moderncivilization, there is an important material basis for human survival and sustainable development.Not only it is essential to improve the people’s material and cultural life, but also to consolidate andstrengthen the defense industry and other fields, we need a large number of high-performance andmulti-level materials. Lead-based piezoelectric Pb(Zr, Ti)O3(PZT) ceramics with highpiezoelectric constant response near morphotropic phase boundary (MPB) are widely used inactuators, transducers and other electromechanical devices. However, the use of PZT piezoelectricceramics has caused serious lead pollution and environmental problems because of the hightoxicity of lead oxide and its high volatility during sintering. Therefore, the development oflead-free piezoelectric ceramics with satisfactory piezoelectric properties attracts much attention.This paper has three parts: First, to obtain excellent electrical and optical properties of theceramics, La is often used as an additive. So a new BNT-based solid solution,(Bi1-xNa0.8K0.2Lax)0.5TiO3was developed. The ferroelectric properties, piezoelectric performances,depolarization mechanism of the ceramics were investigated and discussed. Second, the excellentdielectric-storage properties of the ceramic are ascribed to the reversible relaxor-ferroelectric phasetransition induced by the electric field. In order to achieve high energy density of the BNT-basedceramic,(1-x)Bi0.47Na0.47Ba0.06TiO3-xKNbO3(BNBT-xKN) was synthesized to investigate itsdielectric-storage properties. It is shown that the ceramic BNBT-0.06KN shows excellenttemperature stability for the dielectric-storage application within the measurement range, andfatigue-free load. It is very beneficial to practical applications. Third, a simple chemicalcomposition is favorable to prepare ferroelectrics with good consistence and repeatability for apractical application. So (1-x)(Bi0.5Na0.5)TiO3-xKNbO3(BNT-xKN)(x=0,0.06,0.08,0.10,0.12) ischosen as a basic chemical composition in this study. Our investigation demonstrates thatBNT-xKN ceramic is a more promising lead-free material than BNBT-xKN for dielectric-storagecapacitor application...