Abstract
This paper deals with the effects of the mother salts of PbO, especially Pb2O(OH)2, on the sintering between PbO and PZT by means of X-ray diffraction, thermal dilatometry and electron microscopy. Results obtained are summarized as follows.
(1) The specimen containing PbO(massicot) produced by the decomposition of Pb20(OH)2 showed a remarkably good sintering, and the sintering rate was nearly independent on the sintering temperature in the presence of a liquid phase (PbO). This would be ascribed to the wettability and solubility between liquid (PbO) and solid (PZT) phase.
(2) The powder X-ray diffraction of PbO(massicot) thermally decomposed from Pb20(OH)2 gave a pattern which suggests a prefered orientation of powder particles in the direction of C axis.
(3) By the sintering of the non-stoichiometric PZT associated with the liquid phase(PbO), the shrinkage was proportional to n-th power of the time and the slope of the curve representing this relation was divided into three parts. These parts may correspond to the process of rearrangement of the particle grains, dissolution-recrystallization and grain growth. The value of n in the stage of dissolution-recrystallization was about one third and this coincided with the model by Kingery, that is, this stage would proceed by the diffusion controlled mechanism in the presence of the liquid phase. The activation energy for the initial sintering was in good agreement with that of the grain growth of PZT.
(4) The reaction rate for the formation of PZT was expressed by the equation of the Dander's type and the activation energy was about 96 kal/mol.
(5) The electro-mechanical coupling coefficient of the sintered bodies was about 50% and its dielectric constant was 350-400 at I KHz.
