| The traditional lead-based dielectric ceramics which do harm to the environment and the health of human being can't meet the demands any more with the enhancement of human awareness of environmental protection. The scientists of materials all over the world have aimed at devising a new, nonpolluting, high properties and lead-free dielectric ceramics.Bismuth layer-structured Piezoelectric Ceramics has been considered to be a promising candidate material for lead-free piezoelectric ceramics, because it has higher Curie temperature, small dissipation factor, lower ageing rate and higher resistivity. As the practical shortcomings of single bismith layered material, dielectric and ferroelectric properties had been improved by two method of intergrowth and solid-solve in this thesis. The relation between structure characteristics and electric properties were investigated,which was important to prepare high-performance and practicality of ferroelectric materials.The MBi2Nb2O9-Bi4Ti3O12(M=Ca,Sr,Pb,Ba; abbr.MBN-BTO)and Bi4Ti3O12-MBi4Ti4O15 (M=Ca,Sr,Pb,Ba;abbr.BTO-MBT)intergrowth bismuth layer-structured ceramics had been prepared by tranditional electronic ceramic technology.Except of CBN-BTO, the 2-3 and 3-4 layered intergrowth structure without second phases had been formed.It was found that the relations of dielectric and ferroelectric properties and A ionic radius were close. When the A-ion for Sr2 +, Pb2 +, Ba2 +, ferroelectric properties of MBN-BTO and BTO-MBT were changed to bad with increasing of A ionic radius.For these intergrowth syetems,when Sr2+ ion accounted for A site, lead-free piezoelectric ceramics could be received which had higher Curie temperature and better ferroelectric properties.For 2-3 layered intergrowth structure, the properties were improved by taking La3+ ion into A site of BaBi2Nb2O9-Bi4Ti3O12 ceramics with the worst polarization.when the La3+ content increased, dielectric constant and Curie temperature both increased and the crystal grain shape was changed from flake to stick. In the (SrBi2Nb2O9)x(Na0.5Bi2.5Nb2O9)1-x(abbr. SBNx-NBN) system, the bismuth layer-structured had been formed. The Curie temperature(TC) and dispersion of phase transformation both decreased with the increase in SBN content. The compound with x=0.6 exhibited the enhance electric properties, TC>650℃, 2Pr=18.93μC/cm2, Ec=86.79kV/cm, d33(120℃)=20 pC /N.The dielectric measurement data showed that the ferroelectric characteristics of the compounds were determined by the mixing process of SBN and NBN powder. Compared with the method of mixing after granulation, samples which prepared by the method of mixing before granulation showed higher Curie temperature and weaker relaxor characteristics. (SrBi2Ta2O9)x(BaBi2Nb2O9)1-x (abbr. SBTx-BBN)ceramics were prepared by the method of mixing before granulation.The bismuth layer-structured had been formed without second phases. The crystal grain shape was changed from grain to layered flake with SBT content increasingly. SBTx-BBN had two dielectric peak which were relaxor pesk,and SBTx-BBN were relaxor ferroelectric.The (K0.5Na0.5NbO3)x(SrBi2Nb2O9)1-x (abbr.KNNx-SBN) complex ceramics had been prepared by solild-solve method with bismuth layered structure and perovskite structure. The main crystal structure was SBN phase when x≤0.1.When x>0.1, KxNaySr1-x-yNbO3 perovskite structure was found. The 2Pr and d33 decreased and Curie temperature increased from 451℃to 495℃with the increase in KNN. The samples with x=0.05 exhibited the enhancement of electric properties, 2Pr=19.44μC/cm2, Ec=65.29kV/cm, d33=13pC/N.
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