Dispersion of Lead Zirconate Titanate for Fused Deposition of Ceramics

A study of the adsorption of several surfactants onto lead zirconate titanate (PZT) powder was performed. The adsorption of oleyl alcohol, stearyl alcohol, oleic acid, and stearic acid onto PZT‐5H powder (surface area = 2.58 m 2 /g) was measured by thermogravimetric analysis. Toluene was used as a solvent, and the solution concentrations were set at 50.0 g/L. It was found that the stearic acid adsorption onto the PZT‐5H powder was highest, to the extent of 8.1 mg/m 2 . Trace amounts of stearyl alcohol adsorbed onto PZT, showing an adsorption of 0.8 mg/m 2 . Both oleyl alcohol and oleic acid showed no measurable adsorption. Once stearic acid was found to be a suitable surfactant for fused deposition of ceramics (FDC), the coating process was studied to further optimize the amount adsorbed. A total of six solution concentrations, varying from 5.0 to 70.0 g/L stearic acid in toluene, were tested. It was found that a solution concentration of 30.0 g/L stearic acid was sufficient to provide maximum coverage of the PZT surface. Increases in concentration beyond 30.0 g/L had no effect on the adsorption of the surfactant. PZT powder coated with stearic acid using this method was compounded with a proprietary thermoplastic binder formulation at 55 vol% PZT. Rheology measurements show that this material exhibits a viscosity adequate for FDC.