摘要
用二次合成法制备了（１—ｘ）ＰＭＮｘＰＴ（ｘ＝０．３０，０．３３，０．３５，０．３８）陶瓷，并对其进行了微结构和介电性能研究。Ｘ射线衍射研究结果表明，除０．７０ＰＭＮ０．３０ＰＴ为立方晶系外，其余三种均为四方晶系，其准同型相界位于ＰＴ含量为０．３０～０．３３之间。对试样的ｌｇ１ε－１εｍ与ｌｇ（Ｔ－Ｔｍ）关系研究表明，确定Ｔｍ以上的εＴ特性可引入指数ｎ表征，ｎ值的大小在１～２之间变化。ＰＭＮＰＴ系中ｎ值随ＰＴ含量作连续性变化，表明该体系在立方四方准同型相界两侧介电行为由弛豫铁电体到普通铁电体的过渡是渐变的连续性行为。用Ｄｅｂｙｅ介质理论和有序无序转变理论讨论了准同型相界两侧介电性能的变化，认为准同型相界两侧介电性能的变化与有序微区的尺寸密切相关。
(1-x)PMNxPT(x=030,033,035,038) ceramics were synthesized by columbite precursor method.Their microstructure and dielectric behavior were investigated.XRD results demonstrate that cubictetragonal phase boundary lies between 030 and 033 PT content in PMNPT system.Study on the dielectric properties reveals that the relationship between ε and T(above Tm) can be described by n value,which varies from l to 2.Owing to the continuous change of n with PT content,transformation from relaxor to normal ferroelectric behavior near morphotropic phase boundary(MPB)is considered to be successive and continuous,and is discussed by Debye and orderdisorder transition theory.The results suggest that the dielectric behavior of PMNPT systems near MPB is closely related with the crystal structure and the size of the ordered microdomains.
出处
《硅酸盐学报》
EI
CAS
CSCD
北大核心
1997年第6期688-696,共9页
Journal of The Chinese Ceramic Society
基金
国家自然科学基金
关键词
铌镁酸铅
钛酸铅陶瓷
介电性
铁电体
陶瓷
lead magnesiumniobatelead titanate ceramics,dielectric behavior,ferroelectrics,ordered microdomains,microstructure
