FAST FIRING OF PZT TYPE CERAMICS

摘要

Densification mechanism and piezoelectric performances of some fast fired lead zirconate-titanate ceramics were investigated and evaluated in comparison with those made by conventionally sintering technique. Micro and nano PZT powders prepared by ceramic and chemical methods were used as initial powders for the compacts subjected to the fast and conventionally sinterings. Relatively high density maxima of about 98 % of the theoretical density, were obtained for compacts fast fired at 1350℃(up to 20 minutes soaking times) the best results being obtained for compacts made of nanopowders. The piezoelectric properties of such fast fired compacts proved to be, in some instances, relatively higher or at least comparable to those obtained by conventionally sintering (about 5-6 hours soaking time). Significant increase for d_(33) piezoelectric charge constant was observed in the case of fast fired samples compared to conventionally sintered ones. The electromechanical planar coupling factor k_p was also increased from 0.62 to 0.65 for fast fired samples. The densification mechanism was discussed in terms of a predominantly transient stresses induced during the initial stage of densification by the rather high temperature gradient of the fast fired samples.