Patent ID: 6156091
Filing Date: 2000-12-05
Classification: B22F,C04B

Abstract:
An apparatus for controlling porosity in a gas permeable material fabricated from the process comprising:providing a refractory ceramic or refractory metal material in powder form;selecting a carbon black material in powder form as a fugitive phase having a volume percentage of said refractory material;combining said carbon black material, a binder material, a plasticizer, and a solvent to said refractory material to form a slurry;processing said slurry to form a resulting refractory body; and,controlling porosity of said resulting refractory body by performing thermal cycling, comprising:providing an oxidizing atmosphere with respect to said carbon black;heating at a temperature less than or equal to 500.degree. C. for a first period of time in order to achieve pyrolysis;heating at a temperature greater than or equal to 800.degree. C. and less than or equal to 1100.degree. C. for a second period of time, wherein said binder material and a portion of said carbon black less than said volume percentage are thermally removed from said refractory body, such that a portion of said carbon black remains; and,heating in a temperature range of 1200.degree. C. to 1500.degree. C. for a third period of time such that said refractory body undergoes complete densification, forming a contiguous porous network of refractory material, wherein the volume of said porous network is approximately equal to said volume percentage of said carbon black removed and complete densification of said refractory body.