Low‐Temperature Sintering and Microwave Dielectric Properties of ZnNb 2 O 6 – TiO 2 Ceramics with BaCu ( B 2 O 5 ) Additions

The influence of BaCu ( B 2 O 5 ) ( BCB ) on densification, phases, microstructure and microwave dielectric properties of ZnNb 2 O 6 – x TiO 2 ( x  = 1.70–1.90) composite ceramics have been investigated. Undoped ZnNb 2 O 6 –1.8 TiO 2 ceramics sintered at 1200°C exhibit temperature coefficient of resonant frequency ( τ f ) ~9.25 ppm/°C. When BaCu ( B 2 O 5 ) was added, the sintering temperature of the ZnNb 2 O 6 –1.8 TiO 2 composite ceramics was effectively reduced to 950°C. The results indicated that the permittivity and Q  ×  f were dependent on the sintering temperature and the amounts of BaCu ( B 2 O 5 ). Addition of 3.0 wt% BaCu ( B 2 O 5 ) in ZnNb 2 O 6 –1.8 TiO 2 ceramics sintered at 950°C showed excellent dielectric properties of ε r  = 40.9, Q  ×  f  = 12,200 GHz ( f  = 5.015 GHz) and τ f  = +0.3 ppm/°C.