Gelation of water-based PZT slurries in the presence of ammonium polyacrylate using agarose

Gel casting is a suitable near net shape-forming technique based on the solidification of aqueous suspensions for the production of green parts with interesting economic and environmental benefits. In the present work, PZT-5 suspensions in aqueous media were successfully prepared using ammonium polyacrylate (PAA-NH4) as the dispersing agent. The gelation of the 46–48 vol.% PZT suspensions in aqueous media based on agarose was studied by measuring the height of the samples before and after demoulding. The study found that the suitable amount condition for development of the green parts made was achieved at 0.082–0.19 wt.% agarose (based on dry solid). The density of the green body produced at the optimum content of agarose was determined. A very uniform part with green density of 52% and 55% before and after drying, respectively, was developed. Small shrinkage was measured after drying and heat treating at 550 °C. Sintered samples at 1250 and 1285 °C showed a theoretical density of 99% with an even smaller shrinkage of 16.2%. The dielectric constant and longitudinal piezoelectric charge coefficients, d33, of the selected samples were 2550 and 680 pC/N, respectively.