Preparation and sintering behaviour of nanostructured SrBi 2 Ta 2 O 9 ceramics

Abstract

Nanostructured SrBi₂Ta₂O₉ powders have been prepared by sol-gel processing and the resulting precursors characterised after calcination by DTA-TG and XRD. The results show that pure powders can be obtained above 600°C with a particle size of 60 nm, as determined by TEM. Pressed pellets sintered in air increased in density with increasing sintering temperature, reaching a maximum of 8·42 g cm ^{- 3} after 2 h at 1250°C. In order to improve densification, Bi₂O₃ contents between 3 and 10 wt-% were added to pure SrBi₂Ta₂O₉. The results show that these additions tend to increase density, but that decomposition by volatilisation of Bi₂O₃ at high temperature is retarded to a degree depending on the Bi₂O₃ content. This behaviour is attributed to the increased density resulting from Bi₂O₃ addition, which reduces volatilisation, and hence decomposition, at higher temperatures.