Low-Temperature Sintering Microwave Dielectrics Using CuO-Doped Zn(Nb0.95Ta0.05)2O6 Ceramics
Abstract:The effect of CuO additions on the sintering behavior and microwave dielectric properties of Zn(Nb0.95Ta0.05)2O6 ceramic and its chemical compatibility with Ag have been investigated. The CuO addition can effectively lower the sintering temperature of Zn(Nb0.95Ta0.05)2O6 ceramics to 930°C due to the liquid phase effect. The (ZnCu2)(Nb0.95Ta0.05)2O8 liquid phase will be separated out and exists as a crystalline phase in the final stage. In addition to the (ZnCu2)(Nb0.95Ta0.05)2O8 liquid phase, a second phase Zn3(Nb0.95Ta0.05)2O8 is also detected during the synthesis of specimen. Both phases show a relatively low r and Q×f values compared with that of simple Zn(Nb0.95Ta0.05)2O6. The Q×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° to 930°C for 2 h. For low-firing multilayer applications, a combination of dielectric properties with an r of ∼22.87, a Q×f of ∼77 200 GHz, and a f of ∼−70.8 ppm/°C can be achieved for 4.5 wt% CuO-doped Zn(Nb0.95Ta0.05)2O6 ceramic sintered at 930°C for 2 h.
Document Type: Research Article
Affiliations: Department of Electrical Engineering, National Cheng Kung University, 1 University Road, Tainan 70101, Taiwan
Publication date: 2010-09-01