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Fabrication of Functionally Graded and Aligned Porosity in Thin Ceramic Substrates With the Novel Freeze–Tape‐Casting Process
Author(s) -
Sofie Stephen W.
Publication year - 2007
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.1551-2916.2007.01720.x
Subject(s) - tape casting , materials science , ceramic , porosity , microstructure , fabrication , acicular , lamination , composite material , substrate (aquarium) , casting , filtration (mathematics) , oxide , thin film , metallurgy , nanotechnology , layer (electronics) , medicine , alternative medicine , oceanography , statistics , mathematics , pathology , geology
Functionally graded and continuously aligned pore structures have been fabricated by a modified tape‐casting process for use as solid oxide fuel cell electrodes, catalysts, sensors, and filtration/separation devices. Pore gradients from <5 to 100 μm and aligned pore tubules have been directly fabricated in various ceramic materials with thin substrate sections approximately 500–1500 μm utilizing both low‐toxicity aqueous‐based slips and organic solvents. This process allows for the generation of pores without the use of thermally fugitive pore formers in a single processing step with no need for tape lamination. The incorporation of tape casting, unidirectional solidification, and the freeze‐drying process results in uniformly acicular pores aligned with the direction of the moving carrier film. Processing and microstructure variability will be discussed as it pertains to the effects of solids loading, freezing temperatures, and solvent type. Applications for this ceramic processing technology will also be discussed.