Preparation and characterization of Bi_(0.75)Er _(0.25)O_(1.5) and Bi_(0.75)Er_(0.125)Y _(0.125)O_(1.5) nanocrystalline ceramics by SPS

摘要

Nanopowders of Bi_(0.75)Er _(0.25)O_(1.5) and Bi_(0.75)Er_(0.125)Y _(0.125)O_(1.5) were prepared by a reverse titration chemical coprecipitation method under controlled pH conditions. After calcination at 500 °C for 3 h, powders with grain size in the order of 10 nm were obtained. In order to keep the nanosize of grains, these powders were densified by spark plasma sintering. Samples with relative density higher than 96% were prepared in only 10 min up to 500 °C with an average grain size of 15 and 11 nm for Bi_(0.75)Er _(0.25)O _(1.5) and Bi_(0.75)Er_(0.125)Y _(0.125)O _(1.5), respectively. Impedance spectroscopy revealed slightly higher conductivity for the Bi0.75Er0.125Y0.125O 1.5 composition compared to Bi_(0.75)Er_(0.25)O _(1.5) nanoceramic, but performances remained lower than the corresponding Bi_(0.75)Er_(0.25)O_(1.5) microcrystalline sample. However, mechanical properties of both nanocrystalline ceramics are improved when compared to microcrystalline samples.