Chemically and thermally resistant lanthanoid bititanate ferroelectrics

Studies of the sequence of phases and kinetics of solid state reactions have been made in the systems of some lanthanoid oxides (CeO2, PrO2, Nd2O3, Sm2O3, La2O3) and titanium oxide. Kinetics have been studied both under isothermal and non-isothermal conditions. Application of different equations to the systems is analyzed. All the bititanates examined are being formed above 1200-1500 K. Synthesis of the intermediate product of Ln2Ti2O5 at 1120 K is described by Kroeger-Ziegler equation. The bonding of Ln2O3 with TiO2 at 1470 K proceeds as cylindric phase boundary. Ln2Ti2O7 is formed at 1500-1600 K by bulk diffusion described by Ginstling-Braunstein equation.Production technology of lanthanoid bititanate ferroelectric material resistant to chemically aggressive media and high temperature (TKC470-810 = (1500-2000). 10-6 K-1) is presented.

Keywords:

• kinetics
• solid state reactions
• lanthanoid bititanate
• ferroelectric