Zn含量高的Nb_2O_5-ZnO-Bi_2O_3系高频介质陶瓷

HIGH_FREQUENCY DIELECTRIC CERAMICS OF Nb2O5-ZnO-Bi2O3 SYSTEM WITH HIGH ZnO CONTENT

研究Ｚｎ含量高的Ｎｂ２Ｏ５－ＺｎＯ－Ｂｉ２Ｏ３系高频介质陶瓷．实验结果表明：组成的特征为混合多相结构，除了主晶相为立方焦绿石相之外，随组成变化，尚能生成ＺｎＯ，ＺｎＮｂ２Ｏ６，Ｚｎ３Ｎｂ２Ｏ８，ＢｉＮｂＯ４等相．立方焦绿石相具有高的εｒ，ＺｎＯ相的出现降低εｒ及增大ｔａｎδ，而ＺｎＮｂ２Ｏ６，ＢｉＮｂＯ４等相的出现使εｒ，ｔａｎδ同时降低，并改善电容温度系数．

Dielectric ceramics of Nb2O5-ZnO-Bi2O3 system with high ZnO content is studied in this paper. The XRD patterns indicate that the materials studied are composed of cubic pyrochlore phase (the major crystalline phase), ZnO, ZnNb2O6,Zn3Nb2O8,BiNbO4 etc. Dielectric constant r for the cubic pyrochlore phase is high, the presence of ZnO will decrease r and increase tan, ZnNb2O6 and BiNbO4 will decrease r and tan, but improve the temperature coefficient of capacitance at the same time.