Zr4+B位置换对(Pb0.5Ca0.5)(Fe(0.5)Nb0.5)O3

摘要

研究了Zr4+离子B位置换改性对(Pb0.5Ca0.5)(Fe0.5Nb0.5)O3陶瓷微波介电性能.实验结果表明,(Pb0.5Ca0.5)(Fe0.5Nb0.5)O3(PCFNZ)陶瓷样品呈现单一斜方钙钛矿相结构.随Zr(4+)离子的置换量增加,PCFNZ陶瓷体系的Qr值和晶粒尺寸逐渐减小;介电常数εr随着置换量增加而提高,这主要是因为Zr(4+)的离子极化率(αzr=0.325nm)大于(Fe,Nb)4+离子极化率(αB site=0.313nm).频率温度系数TCF则随置换量增加开始阶段保持不变,而后急剧减小,由正变负值.当烧结温度为1150℃,Zr4+的置换量在y=0.08时,能够获得优良的微波介电性能:Qf=4938GHz,εr=111,TCF=9.06 × 10(6)/℃.%Microwave dielectric properties of B-site substitution by Zr4+ in (Pb0.5 Ca0.5 ) [ (Fe0.5 Nb0.5 ) 1-y Zry] O3 (PCFNZ) ceramics were investigated. All specimens that were substituted by Zr4+ were well sintered and single orthorhombic perovskite phase. Qf values and grain sizes of PCFNZ ceramics decreased with the increase of Zr4+ content. The dielectric constant er increased with the increase of Zr4 + content because of larger ionic polarizability of Zr4+ ion (αZr=0.325nm) than that of (Fe,Nb)4+ ions (aB-site=0.313nm). With the increase of Zr4+ content, the TCF firstly kept almost unchanged, and then drastically decreased from positive to negative. Typically, when Zr4 + content was at y= 0.08, the excellent microwave dielectric properties of Qf = 4938GHz, εr = 111 with TCF=9.06× 10-6/℃　 were obtained.