【作者】 吕宇强；

【导师】 吴裕功；

【作者基本信息】 天津大学 ， 微电子学与固体电子学， 2004， 硕士

【摘要】 本论文将先驱体法引入三元系复合钙钛矿PZT-PMN压电陶瓷系统的制备中。对该系统压电介电性能与烧成制度、配比和Nb5+掺杂的关系进行了研究。首先,在相对较低的1350℃通过两次合成的方法制备了B位先驱体氧化物,XRD表明,(Zr0.5Ti0.5)1-x(Nb2/3Mg1/3)xO2系统在配方x在小于0.3的范围内,均可生成了ZrTiO4单一晶相的固溶体。X衍射物相分析显示, B位的先驱体与A位PbCO3在高于750℃可生成钙钛矿单相。随着Pb(Zr0.5Ti0.5)1-x(Nb2/3Mg1/3)xO3体系的配方x的增加,其达到致密的烧结温度降低,x = 0.05~0.15配方在相对较低的1150℃就可以达到致密。在该系统相图的准同型相界MPB附近靠近四方相一边,即配方x=0.1处,εr,Kp达到最大。对该系统进行微量Nb5+掺杂后,介电常数及机电耦合系数都有不同程度的增大,在加入量为0.02 mol的Nb5+ 时,达到最大值 εr = 1227, tanδ =0.026, Kp = 0.637, d33 = 338×10-12C·N-1。应用强制共沉淀的方法得到了(Pb1-xSrx)CO3(x = 0.05,0.10)固溶体,从SEM照片可以看到粉末为直径约为200nm的棒状颗粒。应用“双先驱体法”,也就是(Pb0.9Sr0.1)CO3与B位先驱体合成可以得到A位Sr2+取代复合钙钛矿。初步的研究发现Sr2+掺杂后,介电性能显著提高,而压电性能由于太低的极化电压并未达到理想,可能是由于烧结温度偏高所造成。更多还原

【Abstract】 In this paper, a B-site precursor method (or two-step calcinations method) was adopted in the preparation of the Pb(Zr0.5Ti0.5)-Pb(Mg1/3Nb2/3)O3 piezoelectric ceramics ternary system. The effect of the sintering conditions and PMN composition on dielectric and piezoelectric properties was investigated. Small amout of Nb2+ was then added to this system as doping to improve the properties. X-ray diffraction indicated that there is only a single phase of ZrTiO4 crystal present for x≤0.3 in the B-site precursor, (Zr0.5Ti0.5)1-x(Nb2/3Mg1/3)xO2, calcined twice at 1350℃. XRD was also applied to identify the perovskite phase. It was found the optimum calcinations condition of perovskite-phase was above 750℃. The sintering temperature decreased with the increasing of composition x and the optimum sintering temperature was about 1150℃ when x was in the range of 0.05~0.15. High piezoelectric and dielectric properties were obtained when the compositions of x were in the tetragonal region near the morphotropic phase boundary (MPB) in phase diagram. Nb5+ was added to the system and When doping amount was 0.02mol, the optimal results of εr = 1227,tanδ =0.0256, Kp = 0.637, d33 = 338×10-12C·N-1 are obtained., but when more Nb5+ was added, the system had a trend of decreasing because of bringing excessive O2+ vacancies. A-site precursor,(Pb1-xSrx)CO3, was prepared by forced coprecipitation method. It can be seen by SEM that the equivalent diameter of rod-typed particle of precursor was about 200nm. So “double-precursor” method was used when it was added to the B-site precursor to form strontium substituting system, the dielectric properties increased distinctly but the piezoelectric properties were not optimal. It may due to the low polarization voltage caused by the high sintering temperature.更多还原