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Pressure Distribution and Defect Formation in Green Ceramic Bodies During Supercritical Extraction of Binder
Author(s) -
Krishnamurthy Kumar,
Lombardo Stephen J.
Publication year - 2009
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2008.02896.x
Subject(s) - supercritical fluid , green body , materials science , supercritical fluid extraction , cabin pressurization , extraction (chemistry) , ceramic , composite material , supercritical carbon dioxide , isothermal process , porous medium , carbon dioxide , volume (thermodynamics) , porosity , mineralogy , chemistry , chromatography , thermodynamics , physics , organic chemistry
Supercritical extraction (SCE) with carbon dioxide at 10–40 MPa and 55°–90°C has been used to remove binder from multilayer green ceramic bodies. Defects such as cracking and delamination were occasionally observed in the green bodies following the extraction process, and these defects were attributed to pressure gradients that arise during isothermal depressurization from conditions of SCE. A model based on flow in porous media was developed to describe the temporal and spatial distribution of pressure within the green body during depressurization. The model incorporates both nonideal pressure–volume–temperature behavior and nonconstant viscosity of the supercritical fluid. The effects of the body size and gas‐phase permeability on the pressure within the green body were examined.