Densification and phase formation in seeded, reactively sintered Sr0.53Ba0.47Nb2O6 ceramics

Abstract

Sr0.53Ba0.47Nb2O6 (SBN53) ceramics were reactively sintered from SrNb2O6 and BaNb2O6 powders. The formation temperature decreased from 1260degreesC for unseeded samples to 1130degreesC for the samples with 15.4 wt% seeds plus 0.85 mol% V2O5 at a heating rate of 4degreesC/min. For the V2O5-free samples, the activation energy was lowered from 554 +/- 15 kJ/mol for unseeded samples to 241 +/- 17 kJ/mol for the samples with 15.4 wt% seeds. In the V2O5-containing samples, densification and phase formation occurred simultaneously. In the V2O5-free samples, however, phase formation was completed before densification. In both cases, ceramics with greater than or equal to95% relative density were obtained. In all cases, SBN53 formed directly, rather than via a variety of intermediate SBN solid solutions. The microstructure evolution was also studied. (C) 2002 Kluwer Academic Publishers.