烧结气氛对CuO添加BiNbO_4陶瓷微波介电性能的影响

Effect of Sintering Atmosphere on Microwave Dielectric Prosperities of CuO-doped BiNbO_4 Ceramics

对不同CuO添加量的BiNbO4陶瓷做了大气和N2气氛烧结研究。结果表明BiNbO4陶瓷对低氧分压气氛非常敏感。BiNbO4在高纯N2气氛下烧结产生大量的空位缺陷致使表观密度发生变化,这种空位缺陷多少与CuO加入量没有明显关系。但添加CuO降低了烧结温度,这种作用在N2条件下表现更为明显,出现了二次结晶现象。N2气氛条件下烧结的陶瓷微波性能没有显著恶化,对系列CuO添加的BiNbO4陶瓷介电常数,品质因数和介电常数温度系数随烧结气氛不同的变化分别作了介绍。

Sintering behavior and microwave dielectric properties of BiNbO4 doped with CuO sintered under ambient and N2 atmosphere were investigated. BiNbO4 ceramics are very sensitive to low oxygen partial pressure atmosphere. The apparent density of the ceramics sintered under high purity N2 is lower than that sintered under ambient atmosphere due to the formation of vacancy defects. By adding CuO, lower sintering temperature can be achieved but vacancy defects not reduced. When specimen sintered under N2, abnormal grain growth occurred severely without impairing microwave properties. The change of dielectric constant, Q factor and temperature coefficient of dielectric constant with the addition of CuO and sintering atmosphere are discussed.