Barium Titanate Perovskite Sintered with Lithium Fluoride

The sintering of barium titanate with, respectively, 1 and 2 wt% LiF for two stoichiometries, Ti/Ba=1 and 0.975, was studied using two calcined powders. One was pure barium titanate; the other contained BaTi0 3 plus BaC0 3 and TiO 2 that did not react when burning. The sintering chronology—intermediate phases, appearance, and disappearance of a liquid phase that has been pointed out for the first time—is directly dependent on the used calcined powder, on the LiF amount, and on the firing schedule. In the same way, the obtained perovskite symmetry varies during sintering from tetragonal to cubic and then to a second tetragonal form, whereas most of the Li and F disappear from the ceramic with two different kinetics.