Ferroelectric ceramics manufactured from nano-sized powders of bi-containing layer-structured phases

Methods to improve dielectric and piezoelectric properties of ferroelectric ceramics with high Curie temperatures (T-C > 700K) are discussed. In the first method improving the electrophysical properties is achieved due to a change in technology of the synthesis of powders of ferroelectric phases, and a proposed technological mode enables one to keep a composition of these powders due to a decrease of temperature of the synthesis of the chemically active powders and to a decrease of temperature of sintering. In this method high-temperature ferroelectric ceramics based on the Aurivillius phases are characterised by the piezoelectric coefficient d(33) 40 pC / N and dielectric permittivity E-33(T)/E-0 230. The second method is concerned with ferroelectric phases of PbTiO3- PbZrO3- Bi4Ti3?(12)- M??iO(3)(M? = Ca, Sr, Ba), and on this basis ceramics are formed with larger piezoelectric parameters and T-C > 700K. Temperature of the synthesis of powders based on ferroelectric phases, obtained using the low-temperature method, is lower by 430K on the average, at reducing the process time range by more than 3times.