Silver cofirability differences between Bi_1.5Zn_0.92Nb_1.5O_6.92 and Zn₃Nb₂O₈

We have investigated systematically the differences of silver cofirability and microwave dielectric properties between Zn₃Nb₂O₈ and Bi_1.5Zn_0.92Nb_1.5O_6.92 (BZN). Two type dopants: 0.29BaCO₃-0.71CuO (BC) and 0.81MoO₃-0.19CuO (MC) were used in Zn₃Nb₂O₈ and Bi_1.5Zn_0.92Nb_1.5O_6.92 ceramics so they can be cofired with silver. The BC-doped ceramics in general have better dielectric properties than those of MC-doped ceramics. The BC-doped Zn₃Nb₂O₈ exhibits better dielectric properties than those of BC-doped BZN (k = 14.7, Q × f = 8200 GHz versus k = 120.1, Q × f = 1050 GHz). For silver compatibility study, the interfacial behaviors between microwave dielectric materials and silver were investigated by using X-ray diffractometer, scanning electronic microscope, and electronic probe microanalyzer. No new crystalline phase and no silver migration behavior were found in the BC-doped Zn₃Nb₂O₈ ceramics cofired with silver, but slight silver migration was detected for BC-doped BZN. But slight silver migration was detected for MC-doped Zn₃Nb₂O₈ and BZN ceramics cofired with silver. Therefore, the good overall properties of BC-doped Zn₃Nb₂O₈ are suitable for microwave applications.