Methods for Synthesis of PbIn_1/2Ta_1/2O₃ with the Perovskite Structure

We have studied the effect of mechanical activation on the synthesis of lead indium tantalate and the formation of the perovskite and pyrochlore phases during both mechanochemical synthesis and subsequent firing. To reduce the electrical conductivity of resulting ceramics, lithium carbonate was added to starting mixtures, which is known to stabilize the perovskite structure. PbIn_1/2Ta_1/2O₃ samples were prepared in the presence of 1–3 wt % superstoichiometric lithium carbonate at firing times from 30 min to 2 h. We have found conditions that ensure the preparation of single-phase material with the perovskite structure in the presence of lithium carbonate additions at different firing temperatures. The sequence in which reagents are introduced into the starting mixture and their activation have been shown to have a significant effect on the synthesis of the tantalate and the formation of the perovskite phase. We have compared a number of sample preparation procedures differing in mechanical activation conditions and the way in which the starting materials are introduced. Optimal conditions have been found which ensure the preparation of piezoceramics containing the maximum amount of the perovskite phase and having the highest density.