Studies on Sintering between PbO and PZT (Part 2)

The Effects of Average Particle Size of Raw Powder on Sintering

Abstract

Lead titanate-zirconate ceramics has been usually carried to synthesize at about 1300°C in PbO atmosphere. The author has attempted to synthesize non-stoichiometric PZT with excess of PbO in a previous paper.
In this paper, it was described that PbO-PZT ceramics with high density, low water absorption and high piezoelectric characteristics were produced by sintering fine powders. Samples were formed with raw powders of particle size 4.2, 3.5, 1.2 and 0.5μ in average respectively. Shrinkage, density, water absorption and electric characteristics were measured in relation with sintering time, temperature and the particle size. The structure of sintered ceramics was examined by the electron micrograph.
The following results were obtained.
(1) The shrinkage and density of this ceramics increased with the decrease in particle size of raw powders, especially in the case of 0.5μ powders the water absorption was below 0.1% by sintering 900°C for 2 hr.
(2) It was observed by electron micrograph that the liquid phase (PbO) remarkably penetrated into the grain boundary of PZT in the use of finer powder.
(3) Electro-mechanical coupling coefficient K was around 43% by sintering the 0.5μ powders at 900°C for 3 hours.