Dispersion of Lead Zirconate Titanate for Fused Deposition of Ceramics

Abstract

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.

Rapid Prototyping of Novel Piezoelectric Composites

“…There have been studies conducted that establish the efficacy of each surfactant in reducing the viscosity of the filled systems to values that permit their use in FDC. In the case of stearic acid and ECG9 system, the stearic acid molecule is thought to function primarily as a dispersant for the case of PZT/ECG9 as discussed by McNulty [42].…”

“…The exact values of shrinkage vary from one material to another. The shrinkage values for PZT are 16% and 20% respectively [39,42]. As can be seen from the shrinkage values for PZT, there is significant anisotropy in the shrinkage i.e.the shrinkage in the build direction tends to be higher than in the build plane directions [39,42].…”

“…McNulty fabricated PZT-based piezoelectric ceramic/polymer tube hydrophones using FDC [42]. A new family of thermoplastic binder formulations were developed to enable the fabrication of the intricate geometry of the transducers, which essentially were of (3-1), (3-2) and (2-2) connectivity, as shown in Fig.…”

“…The shrinkage values for PZT are 16% and 20% respectively [39,42]. As can be seen from the shrinkage values for PZT, there is significant anisotropy in the shrinkage i.e.the shrinkage in the build direction tends to be higher than in the build plane directions [39,42]. In order to develop the FDC process into a robust and reliable manufacturing technique the shrinkage values (after sintering) as well as the associated uncertainty, for all the materials used in FDC needs to be quantified.…”

Advances in Fused Deposition Modeling

“…McNulty et al (59) studied the essential requirements of feedstock filaments for the FDC process because the key to the success of the FDC is the filaments with required mechanical and rheological properties. They investigated the effect of several surfactants on the lead zirconate titanate (PZT) powder and found that the stearic acid was a suitable surfactant for FDC to aid coating and dispersion of the powder in the polymer matrix used to make filaments.…”