银掺杂对Bi_2O_3-ZnO-Nb_2O_5系陶瓷介电及熔融物性的影响

Effects of Ag-Dopant on Dielectric Properties and Melting Behaviors of Bi_2O_3-ZnO-Nb_2O_5 (BZN)-Based Ceramics

在ＢＺＮ系陶瓷中，立方焦绿石结构的α相与低对称结构的β相是二个重要的基本物相，α相是熔点为１１９０℃的同成分熔融化合物，对应负温度系数，β相是转熔温度为１１００℃的异成分熔融化合物，对应正温度系数，α相与β相接一定比例组成（α＋β）复相瓷料，得到ＣＨ组零温度系数．分别在α相、β相以及ＣＨ组复相瓷料中进行银掺杂，通过瓷料介电性能的研究，首次明确了银掺杂对α相、β相以及ＣＨ组复相瓷料介电性能的不同影响和影响程度，进一步研究银掺杂β相瓷料的熔融物性，结果表明银掺杂对瓷料熔融物性的影响是影响其介电性能的内因．

Cubic pyrochlore structure alpha phase and low symmetry structure beta phase are the basic phases of BZN-based ceramics. The a phase is a congruent compound, its congruent melting point is 1190 degreesC, corresponding to negative temperature coefficient of dielectric constant. The beta phase is an incongruent compound, its incongruent melting point (peritectic temperature) is 1100 degreesC, corresponding to positive temperature coefficient. The zero temperature coefficient of CH grade would be met with fixed alpha/beta phase ratio. In this paper, dielectric properties of Ag-doped BZN-based alpha phase, beta phase and CH grade diphasic ceramics were explored respectively. The results show the effects of Ag-dopant on the dielectric properties of BZN-based alpha phase, beta phase and CH grade diphasic ceramics. The melting behaviors of Ag-doped BZN-based beta phase were explored too. The change of incongruent melting point results in the change of the dielectric property of Ag-doped BZN-based ceramics.