The Investigation On Properties Of BaTiO₃Based Lead-free Piezoelectric Composite Ceramics

Barium titanate (BaTiO3) as a kind of perovskite type dielectric materials, has high dielectric constant. The Curie temperature of BaTiO3is120℃. According to the development station of lead-free piezoelectric ceramics, this paper will ascertain the study of the BaTiO3ceramics.We build up a matrix-particle theoretical model to analyze that the internal stress affects the Curie temperature and piezoelectric coefficient. The Curie temperature and piezoelectric coefficient of BaTiO3--ZrO2ceramic was investigated as a function of volume percentage of ZrO3.ZnO-B2O3-SiO2(ZBS) glass powder with small grain size was synthesized by a sol-gel method. Low temperature sintering at1100℃of high density ceramic was realized through ZBS glass powder adding. The influence of density with amount of glass powder was investigated. In liquid sintering, we study the density, crystal lattice, microstructure and dielectric properties of ceramic prepared using different particle size of raw powders. The ceramic with good piezoelectric property was obtained by adding MnCO3, which increase density and reduce the dielectric loss of ceramic.lmol%Y2O3--ZrO3nanopowder was synthesized by a Pechini method, and BaTiO3--ZrO2composite ceramic was prepared. The effects of density, phase and dielectric properties of ceramic with sintering temperature was researched. The Curie temperature of BaTiO3ceramic is increased by adding ZrO2. BaTiO3--10vol%ZrO2composite ceramic has the highest dielectric constant and a Curie temperature (Tc=143℃) at sintering temperature of1050℃. The internal stress is the reason for the increase of the Curie temperature by Raman spectroscopy. With the increase of ZrO2content, the Curie temperature moves to high temperature.Bi and Cu co-doped BaTiO3ceramics were prepared through solid-state reaction and liquid method respectively. The influence of microstructure, morphology, dielectric and piezoelectric properties of (Ba1-2xBi2X)(CuxTi1-x)O3ceramic with the amount of Bi and Cu doping was investigated. The process conditions has been analyzed to prepare (Ba1-2xBi2X)(CuxTi1-x)O3by self-combustion method. The effects of sintering condition on the microstructure, phase, dielectric and piezoelectric properties of (Ba1-2XBi2X)(CuxTi1-x)O3ceramics was investigated. The x=0.005sample has the Curie temperature (Tc=140℃), piezoelectric constant d33=100pC/N, d31=-18.44pC/N, and Kp=17.62%at temperature of Ti=1300℃, T2=1150℃. While the x=0.01sample has the Curie temperature (Tc=150℃), piezoelectric constant d33=80pC/N,d31=-9.88pC/N and Kp=13.88%at same condition. In addition, the piezoelectric constant d31and electromechanical coupling facor Kp have a good temperature stable property. Finally,(Ba1-2xBi2x)(CuxTi1-x)O3--ZrO2composite ceramics have prepared and investigated.