固溶率因子R对(Pb,Ca,La)(Fe,Nb)O_3陶瓷微波介电性能的影响

作者：杨秋红 金应秀 徐军 

单位：上海大学材料学院 韩国京畿大学陶瓷工程系 中国科学院上海光学精密机械研究所 上海201800  水原442-76 韩国  上海201800 

关键词：微波介质陶瓷  铌酸盐  固溶率因子  容忍因子  介质极化率 

分类号：TQ174.1

出版年,卷(期):页码：2002,30(5):554-558

DOI：

摘要：

研究了A位La3+ 的电荷平衡取代 [(Pb0 .5Ca0 .5) 1 -xLa2x/3] (Fe0 .5Nb0 .5)O3和电荷非平衡取代 (非化学计量化合物 ) [(Pb0 .5Ca0 .5) 1 -xLax]·(Fe0 .5Nb0 .5)O3+δ(PCLFN)系统的微波介电性能。研究结果表明 ,实际的取代式是 [(Pb0 .5Ca0 .5) 1 -xLa2x/3+R( 1 -x) ] (Fe0 .5Nb0 .5)O3+δ,其中R是固溶率因子 ,它影响着A位La3+ 取代陶瓷的微波介电性能。当R >0时 ,A位的电荷平衡取代 [(Pb0 .5Ca0 .5) 1 -xLa2x/3] (Fe0 .5Nb0 .5)O3将增加其介电损耗 ,x =0 .0 5～ 0 .10时 ,Qf<80 0="" 1="" 2="" 75="" pb0="" .5ca0="" fe0="" .5nb0="" pb="" .0="" x="0" k="">10 0 ,Qf值为 5 5 2 5～ 610 5GHz ,频率温度系数αf 为 7× 10 - 6 ～ 15 .7× 10 - 6 /℃ ,当x =0 .10时 ,Qf值达到极大值 64 82GHz。

Microwave dielectric properties of [(Pb 0.5 Ca 0.5 ) 1- x La 2 x /3 ](Fe 0.5 Nb 0.5 )O 3 and [(Pb 0.5 Ca 0.5 ) 1- x La x ](Fe 0.5 Nb 0.5 )O 3+ δ in which A_sites were partly substituted by La 3+ were investigated. It is suggested that the actual substitution is in the formula [(Pb 0.5 Ca 0.5 ) 1- x La 2 x /3+ R (1- x ) ](Fe 0.5 Nb 0.5 )O 3+ δ , where R is a solid-solution ratio factor affecting the microwave dielectric properties of A_site substitution ceramics. The A_site charge balance substitution of [(Pb 0.5 Ca 0.5 ) 1- x La 2 x /3 ](Fe 0.5 Nb 0.5 )O 3 increased its dielectric loss. When R >0 and x =0.05-0.10, the Qf value was less than 800 GHz. In contrast, the A_site charge unbalance substitution of [(Pb 0.5 Ca 0.5 ) 1- x La x ](Fe 0.5 Nb 0.5 )O 3 improved its microwave dielectric properties by the fact that the surplus of La 3+ and (Pb,Ca) 2+ eliminates oxygen vacancies in the solid solution. A single perovskite phase is formed when x ≤0.02. However, surplus La 3+ would cause the formation of the secondary phase (pyrochlore phase) and the amount of the secondary phase was proportional to the amount of surplus La 3+ . The decreasing of the dielectric constant K with x value is caused by the formation of pyrochlore phase. At x =0.02-0.075, the dielectric constant is above 100, the value of the quality factor Qf is 5 549-6 105 GHz, and the temperature coefficient of resonant frequency( α f ) is in the range of 7×10 -6 -15.7×10 -6 /℃. At x =0.1, the Qf value reached the maximum of 6 482 GHz.

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参考文献：

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