Low-temperature fabrication of BaBi₂Nb₂O₉ ceramics by reaction controlled sintering

摘要

Reaction controlled sintering was applied to the fabrication of BaBi₂Nb₂O₉ (BBN) ceramics at lower temperature. A powder mixture of BaCO₃ and Nb₂O₅ was heated at 600 °C in a 1st step calcination to produce a binary precursor of BaNb₂O₆. The pre-heated powder was then mixed with a fixed amount of Bi₂O₃, which was subsequently pressed into a disk pellet. After a powder compact of the mixture was subjected to heating at 950 °C for 4 h, a BBN bulk sample with a relative density of 92% was successfully obtained. The low-temperature fabrication of dense BBN ceramics could be attributed to the inhibited formation of an intermediate phase of Ba₅ Nb₄O₁₅ and the production of submicron powder with an appropriate reactivity during a 1st step calcination.