（Pb、Ca、La）TiO_3陶瓷的溶胶－凝胶制备和特性

Preparation and Characteristics of (Pb、Ca、La) TiO_3 Ceramics by Sol-gel Process

用溶胶－凝胶工艺制备了Ｐｂ_（０．９５－ｘ）Ｃａ_（０．０５）Ｌａ_ｘＴｉ_（１－ｘ／４）Ｏ_３（Ｘ＝０．０５～０．２）系统的微粉和陶瓷，该材料密度可达理论密度值的９０％以上。研究了该陶瓷的物理和电性质，所测得热释电系数ｐ＝２．２０×１０^（－８）～３．１７×１０^（－８）Ｃ／ｃｍ~２·Ｋ，并具有负温度系数效应。讨论了对应Ｔｉ—Ｏ_Ｉ伸缩振动铁电软模和Ｏ_Ｉ－Ｔｉ－ＯＩＩ、（Ｐｂ、Ｃａ、Ｌａ）－（ＴｉＯ_３）的弯曲振动红外和远红外吸收光谱。根据陶瓷极化前后ＸＲＤ谱强度的变化，计算了该陶瓷极化后电畴在空间的择优取向分布。

Ultrafine powder and ceramics of Pb0.95-xCa0.5LaxTi1-x/4O3(X=0.05～ 0.2)system were prepared by sol-gel process.The density of resultant materials is above 90% of the theoretlcal value.The detailed physical and ferroclectric properties of the ceramics were investigated,including pyroelectrie coefficient p=2.20×10-8～3.17×10-8 C/cm2·K and a NTC(Negative Temperature Coefficient) effect. IR and FIR absorption band referred to the ferroelectric soft mode of Ti-O1 stretching and O1-Ti-O11、(Pb、Ca、La)-(TiO3)bending vibration have been discussed.The space orientation distribution of the domains in polarized ceamic was calculated according to XRD spectra intensity variation before and after polarization of PCLT ceramics.