Low-Temperature Sintering Microwave Dielectrics Using CuO-Doped Zn(Nb0.95Ta0.05)2O6 Ceramics

The effect of CuO additions on the sintering behavior and microwave dielectric properties of Zn(Nb0.95Ta0.05)(2)O-6 ceramic and its chemical compatibility with Ag have been investigated. The CuO addition can effectively lower the sintering temperature of Zn(Nb0.95Ta0.05)(2)O-6 ceramics to 930 degrees C due to the liquid phase effect. The (ZnCu2)(Nb0.95Ta0.05)(2)O-8 liquid phase will be separated out and exists as a crystalline phase in the final stage. In addition to the (ZnCu2)(Nb0.95Ta0.05)(2)O-8 liquid phase, a second phase Zn-3(Nb0.95Ta0.05)(2)O-8 is also detected during the synthesis of specimen. Both phases show a relatively low epsilon(r) and Q x f values compared with that of simple Zn(Nb0.95Ta0.05)(2)O-6. The Q x f value is a function of the sintering temperature and the amount of CuO addition. With 4.5 wt% CuO addition, it varies from 8500 to 77 200 GHz as the sintering temperature increases from 840 degrees to 930 degrees C for 2 h. For low-firing multilayer applications, a combination of dielectric properties with an epsilon(r) of similar to 22.87, a Q x f of similar to 77 200 GHz, and a tau(f) of similar to-70.8 ppm/degrees C can be achieved for 4.5 wt% CuO-doped Zn(Nb0.95Ta0.05)(2)O-6 ceramic sintered at 930 degrees C for 2 h.