Densification and phase formation in seeded, reactively sintered Sr_0.53Ba_0.47Nb₂O₆ ceramics

Sr_0.53Ba_0.47Nb₂O₆ (SBN53) ceramics were reactively sintered from SrNb₂O₆ and BaNb₂O₆ powders. The formation temperature decreased from 1260°C for unseeded samples to 1130°C for the samples with 15.4 wt% seeds plus 0.85 mol% V₂O₅ at a heating rate of 4°C/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 ≥95% 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.