The Preparation And Properties Research Of SBT-NBT-KBT Piezoelectric Ceramics

Bismuth layer-structured ferroelectricceramicswith high Curie temperature,low dielectric constant,low loss of resonant frequency,makingthem become a candidate material in high temperature and high frequency resonance applications.SrBi₄Ti₄O₁₅?SBT?,Na_0.5Bi_4.5Ti₄O₁₅?NBT?,and K_0.5Bi_4.5Ti₄O₁₅?KBT?are all four-layer orthogonal ferroelectric phasepiezoelectric ceramics.However,there isn't any report about structure and properties of SBT with various NBT and KBT content.Sr_0.9((Na_1-xK_x)_0.5Bi_0.5)_0.1Bi₄Ti₄O₁₅?x=0.0,0.12,0.16,0.2,0.24,0.28,0.32??SNKBT?ceramics were prepared via the traditional solid-state reaction method.In this work,we study the calcination temperature and sintering temperature.The crystal composition and piezoelectric properties of Sr_0.9((Na_1-xK_x)_0.5Bi_0.5)_0.1Bi₄Ti₄O₁₅ were investigated.With the increase of K_0.5Bi_4.5Ti₄O₁₅ content,the curie temperature of SNKBT solid solution ceramics slightly enhanced,and the excellent properties were obtained for Sr_0.9((Na_1-xK_x)_0.5Bi_0.5)_0.1Bi₄Ti₄O₁₅?x=0.24?ceramics sintered at 1050°C for 3 h:d₃₃=20 pC/N,tan?=0.40%,Tc=569°C.In addition,CeO₂?A-site?and Co₂O₃?B-site?modified on the structures and properties of Sr_0.9((Na_0.76K_0.24)_0.5Bi_0.5)_0.1 Bi₄Ti₄O₁₅ ceramics were studied.The properties of Sr_0.9((Na_0.76K_0.24)_0.5Bi_0.5)_0.1Bi₄Ti₄O₁₅+0.50 wt%CeO₂ ceramics were the best.It is found that the T_C shifts to high temperature slightly with the modification.The piezoelectric properties of SNBT ceramics weresignificantly enhanced and the dielectric loss sharply decreased withcerium doping.The Curie temperature?Tc?,piezoelectric constant(d₃₃)and dielectric loss for the 0.50 wt%Ce-modified SNKBT solid solutions were found to be 600°C,26 pC/N and 0.20%,respectively.In the following studies,the B-site Comodified SNKBT ceramics are investigated.The Curie temperature?Tc?,piezoelectric constant(d₃₃)and dielectric loss for the x=0.06cobalt-modified SNKBT ceramics were found to be 608°C,27 pC/N and 0.13%.Temperature dependence of d₃₃ for A-site Ce and B-site Co modified SNKBT ceramics was found to bestable up to 500°C,which can be applied in the high temperature filed.