ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 54, (2) 103 - 107 (2010)


LOW-FIRED BiNbO₄ MICROWAVE DIELECTRIC CERAMICS MODIFIED BY CuV₂O₆ ADDITION SINTERED IN N₂ ATMOSPHERE
 
Zhong Chaowei, Yuan Ying, Zhang Shuren, Pang Yue, Tang Bin
 
State key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People’s Republic of China

Keywords: BiNbO₄, Microwave ceramics, Low-fired, Dielectric properties, Sintering aid
 

The sintering behavior, microstructure and microwave dielectric properties of BiNbO₄ ceramics sintered in N₂ with CuO and V₂O₅ additions were investigated. The CuO and V₂O₅ additives, acting as the sintering aids, could effectively lower the sintering temperature of BiNbO₄ ceramics. CuV₂O₆, formed by the reaction between CuO and V₂O₅ with the mole ratio of 1:1 at 500°C, was more effective to realize low-temperature sintering of BiNbO₄ ceramics than the CuO–V₂O₅ mixture. It was found that the addition of 0.1 wt% CuV₂O₆ to BiNbO₄ lowered the sintering temperature to approx 880°C while maintaining 98.4 % theoretical density. Pure orthorhombic BiNbO₄ phase was obtained successfully in the cases of CuO–V₂O₅ mixture or CuV₂O₆ additions. The CuO–V₂O₅ mixture addition would cause inhomogeneous and abnormal grain growth resulting in the degradation of densities and dielectric properties of BiNbO4 ceramics. By contrast, a uniform and dense microstructure was obtained in BiNbO₄ ceramics with CuV₂O₆-addition, contributed to higher dielectric constant and quality factor. The BiNbO₄ ceramics with 0.5 wt% CuV₂O₆ addition sintered at 860°C for 2 h have good microwave dielectric properties (at 4.3 GHz):relative dielectric constant (εr) = 47, quality factor (Q×f) = 11950 GHz.


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