Synthesis of ferroelectric perovskites through aqueous-solution techniques

Abstract

The hydrolysis of niobates in aqueous solutions has been applied to the coprecipitation of PbNb2/3Mg1/3O3 leading to a low temperature synthesis of this ferroelectric relaxor ceramic. The effect of hydrolysis conditions - such as the concentration of bases and acids used, their rates of addition and the nature of the precursors salts - is described. The perovskite phase appears after heating at 350 °C and is obtained as a pure phase at 800 °C after heat treatment for 1 h. Relaxor ferroelectric ceramics with a high dielectric constant can be obtained by sintering at 1000 °C. The process has been also applied to the synthesis of other relaxor ceramic compositions such as PZN (PbNb2/3Zn1/3O3) and PFN (PbNb1/2Fe1/2O3) compounds.