Extraction of Stearyl Alcohol Binder from Compacts of Chemically Prepared PLZT Powders with Supercritical Carbon Dioxide

Abstract

Different agglomerated powders of PLZT were prepared from aqueous nitrate solutions using two preparation methods. The microstructure developed during calcination at 450°-470°C was determined by powder characteristics such as crystalline phase, particle morphology and size, agglomeration, and surface area. Green compacts containing 5wt% stearyl alcohol binder were fabricated by uniaxial pressing. Extraction of the binder was carried out with supercritical carbon dioxide at 35°-65°C under the pressure of 9.81MPa or 19.6MPa. The degree of agglomeration of calcined powders influenced the extraction. The extraction process is discussed on the basis of mass-transfer resistance in compacts and chemical affinity between powder surface and stearyl alcohol.