本文选择了A位复合钙钛矿型铁电体材料钛酸铋钠(Bi0.5Na0.5TiO3，简称BNT)作为研究的基材。借鉴含铅压电陶瓷改性研究的思路，对BNT陶瓷进行了系列的固溶改性研究，优化压电与铁电性能，达到实用化的目的。 采用传统固相反应法制备了致密的(0.944-x)Bi0.5Na0.5TiO3-0.056BaTiO3-xSrTiO3(简写为0.944BNT-0.056BT-100xST)和(1-x)(0.93Na0.5Bi0.5TiO3-0.07BaTiO3)-xKNbO3(简写为0.93BNT-0.07BT-100xKN)陶瓷，在所研究的组成范围内，两组材料体系均形成了单一的钙钛矿结构，根据XRD谱确定出0.944BNT-0.056BT-100xST系列陶瓷的准同型相界(MPB)范围为0.03mol%≤x≤0.06mol%，SrTiO3的引入能够有效的细化晶粒，使弥散相变特征显著，并有效改善了材料的铁电和压电性能，x=0.04mol%时，材料得到较优的综合性能：相对介电常数εr=4632，介电损耗tanδ=0.01576，剩余极化强度Pr=35uC/cm2，矫顽场Ec=21kV/cm，压电常数d33=134pC/N；对于0.93BNT-0.07BT-100xKN陶瓷，随着KNbO3的引入，系列陶瓷体系材料更易烧结，材料的相对介电常数逐渐减小，材料具有较高的矫顽电场，x=0.05mol%时，压电常数最大为118pC/N。 在具有准同型相界组成点的Na0.5Bi0.5TiO3-SrTiO3固溶体系基础上引入BaTiO3和KNbO3，采用固相反应法分别制备了致密的(0.7-x)Na0.5Bi0.5TiO3-0.3SrTiO3-xBaTiO3(简写为0.7BNT-0.3ST-xBT)和(1-x)(0.72Na0.5Bi0.5TiO3-0.28SrTiO3)-xKNbO3(简写为0.72BNT -0.28ST-xKN)陶瓷。XRD表明，在材料组成范围内，系列0.7BNT-0.3ST-xBT样品的晶体结构均为四方相结构，x=0.055mol%时，d33达最大131pC/N；通过对0.72BNT -0.28ST-xKN固溶改性体系陶瓷的研究发现，KN的引入不改变基础体系材料的三方-立方相结构。利用三种弛豫模型对0.72BNT-0.28ST-xKN系列陶瓷材料的介电损耗的弛豫现象进行定量分析，发现新玻璃模型拟合程度最好。分析得出材料介电弛豫现象主要来源于极性微区向铁电微畴的转化的结果。高温介电谱中系列材料弥散程度随KN的引入逐渐增强，并且Td和Tm峰之间的界限逐步减小，趋于合并。 对于(1-x)(0.93BNT-0.0665BaTiO3-0.0035BaZrO3)-xCaTiO3(简写为0.93BNT-0.07BZT -100xCT)体系材料，在所研究的组成范围内，CT不改变基础体系的MPB结构，且随CT含量的增加，陶瓷晶粒细化。适量CaTiO3的引入能使体系材料的居里温度提高，使材料的反铁电相区域增加，获得较优的铁电性。材料的弛豫度随CT相的引入逐渐增强。 对于(1-x)(0.92BNT-0.06BT-0.02ST)-xLiSbO3(简写为0.92BNT-0.06BT-0.02ST-100x SL)体系材料，XRD图谱表明，少量的SL引入不会影响0.92BNT-0.06BT-0.02ST的晶体结构，当x≥0.06mol%时，陶瓷材料中出现第二相。SEM显示SL促进了0.92BNT- 0.06BT-0.02ST晶粒的生长，介电温度特性曲线显示，材料逐渐由两个介电反常峰逐渐转变为一个宽化的介电峰，随SL的引入，电滞回线逐渐由类似于反铁电体的“双电滞回线”向细长的单电滞回线转变。

Sodium bismuth titanate(Bi0.5Na0.5TiO3, abbreviated as BNT), is a kind of A-site substituted perovskite-type ferroelectric. In this paper, BNT was choosed as the research base material. In order to improve the properties of piezoelectric and ferroelectric and achieve the practical purpose of BNT ceramics, a series of solid solution modification research had been taken on BNT ceramics according to the research ideas of lead based piezoelectric ceramics. The dense lead-free piezoelectric ceramics (0.944-x)Bi0.5Na0.5TiO3-0.056BaTiO3-xSrTiO3 (abbreviated as 0.944BNT-0.056BT-100xST) and (1-x)(0.93Na0.5Bi0.5TiO3-0.07BaTiO3)- xKNbO3(abbreviated as 0.93BNT-0.07BT-100xKN) were fabricated via conventional ceramic technique. In the study of their composition range, the X-ray diffraction (XRD) analysis revealed that the two sets of ceramic systems form a single perovskite structure, and the morphotropic phase boundary(MPB) between the rhombohedral and tetragonal phases of 0.944BNT-0.056BT-100xST was identified in the composition range of 0.03≤x≤0.06mol%, the grain size decrease with the increase of ST content, the diffuse phase transition characteristics is significant, The dielectric and ferroelectric properties are further improved with the introduce of ST component. When x=0.04mol%, the ceramics exhibit excellent properties: relative dielectric constant εr=4632, dielectric loss tanδ=0.01576, remnant polarization Pr=35uC/cm2, and coercive field Ec=21kV/cm, Piezoelectric constant d33=134 pC/N. For 0.93BNT-0.07BT-100xKN ceramics, series of ceramic materials become easier sintering with the introduce of KNbO3, the relative dielectric constant decrease, ceramics have high coercive field, the maximum piezoelectric constant is 118 pC/N at x=0.05mol%. BaTiO3 and KNbO3 were added to Na0.5Bi0.5TiO3-SrTiO3 system, the composition point of BNT-ST system was choosed in the MPB. The dense (0.7-x)Na0.5Bi0.5TiO3-0.3SrTiO3 -xBaTiO3(abbreviated as 0.7BNT-0.3ST-xBT) and (1-x)(0.72Na0.5Bi0.5TiO3-0.28SrTiO3)-x KNbO3(abbreviated as 0.72BNT-0.28ST-xKN) ceramics were respectively prepared by the solid state reaction method. XRD spectrums showed that the crystal structure of 0.7BNT -0.3ST-xBT samples are tetragonal structure in their composition ranges. The d33 reach the maximum 131pC/N at x=0.055mol%; By study modified 0.72BNT-0.28ST-xKN solid solution ceramics we can found the introduce of KN does not change the rhombohedral-cubic crystal structure of the basic material systems. The dielectric loss relaxation phenomenon of 0.72BNT-0.28ST-xKN ceramics was quantitatively analysised by three kinds of relaxation model. The new glass model coincide well, the phenomenon of dielectric relaxation mainly originate from the polarity of the micro-region to the ferroelectric micro-domain. The dispersion degree of series materials gradually increase with the introduction of KN in high temperature dielectric spectrum. The boundaries between Td and Tm peaks reduce gradually and tend to merge. For (1-x)(0.93BNT-0.0665BaTiO3-0.0035BaZrO3)-xCaTiO3(abbreviated as 0.93BNT- 0.07BZT-100xCT) ceramics, CT does not change the MPB phase of basic material system. The grain size decrease with the increase of CT content. The Curie temperature and ferroelectricity raise with introduced appropriate amount of CaTiO3, the region of antiferroelectric phase increase for series ceramics. The relaxation degree gradually increase with the introduce of CT. For (1-x)(0.92BNT-0.06BT-0.02ST)-xLiSbO3(abbreviated as 0.92BNT-0.06BT-0.02ST -100xSL) ceramics, XRD analysis showed that small amount of SL does not change the crystal structure of 0.92BNT-0.06BT-0.02ST, the second phase appear at x =0.06mol%, SEM micrographs revealed that SL promote the growth of 0.92BNT-0.06BT-0.02ST grains, the dielectric temperature characteristic curves showed ceramics gradually transform from two dielectric anomalous peak to one broad dielectric peaks, with the introduction of SL, the hysteresis loops transform from "double hysteresis loops" which are similar to the antiferroelectrics to the elongated single electric hysteresis loops.