Preparation and sintering behaviour of nanostructured SrBi2Ta2O9ceramics

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.