Low temperature sintering of PZT powders coated with Pb5Ge3O11 by sol-gel method

Low temperature sintering of PZT powders was investigated using Pb5Ge3O11(PGO) as a sintering aid. PZT powders with 150 nm particle size were coated with PGO which was prepared from precursor solutions of Ge(OiPr)(4) and Pb(NO3)(2) by sol-gel method. 1 wt% PGO-added PZT powders were densified at 750 degrees C for 2h to sintered bodies with the relative density of approximately 95%. An addition of PGO improved the sinterability of PZT powders with a reduction of sintering temperature by about 300 degrees C. Dielectric and piezoelectric properties of PGO-added PZT ceramics sintered at less than or equal to 950 degrees C were superior to those without PGO additives. However, a higher sintering temperature above 1000 degrees C deteriorated the dielectric and piezoelectric properties of PGO-added PZT ceramics. This may be attributed to the change of microstructure involving the formation of solid solution between PZT and PGO. The I wt% PGO-added PZT bodies sintered at 750 degrees C exhibited an electromechanical coupling factor, Kp, of about 56%. (C) 1999 Elsevier Science Limited. All rights reserved.