Fabrication of Bismuth Layer Structured Ferroelectric Ceramics by Reaction Controlled Sintering

Abstract

Reaction controlled sintering （RCS） was applied to the formation of multicomponent compounds in the Aurivillius family, BaBi₂Nb₂O₉ （BBN） and BaBi₄Ti₄O₁₅ （BBIT）, to produce densified bulk samples at a lower temperature. In the RSC process, binary compound powders of BaNb₂O₆ and Bi₄Ti₃O₁₂ preformed by 1^st-step calcination were mixed with powders containing the third component, Bi₂O₃ and BaTiO₃, for the production of BBN and BBIT, respectively. They were formed into powder compacts and heated to a fixed temperature during which both reaction and densification proceed. Changes in the extent of reaction and fractional shrinkage with heating temperature were evaluated in each system. It is essential to elucidate the reaction route by which the required solid phase could be obtained at lower temperature and then to optimize a processing factor correlated to the reaction and densification activities of the materials involved.