Phase formation and reactions in the Bi_2O_3-ZnO-Nb_2O_5-Ag pyrochlore system

摘要

Mixed-phase compositions in the Bi_2O_3-ZnO_5 pyrochlore system have been previously identified as potential low-fire dielectric composites for high-frequency multilayer devices. However, there has been a problem with the ability to co-process this material with silver. It was found that an intermediate BiNbO_4 phase that occurs during calcination can interact with silver during co-sintering, forming a deleterious phase. Processing routes to control the presence of remanent BiNbO_4 were investigated. Such as ZnO stoichiometric adjustment, low partial pressure of oxygen sintering atmosphere, and specific temperature-time dwells.