Aluminum borate ceramics and process for producing same
AssigneeCoors Porcelain Company
InventorMichael J. Readey
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Abstract
The present invention provides an aluminum borate ceramic having a high porosity and a tightly controlled pore size distribution, while maintaining good mechanical strength. The ceramic body can be formed by decomposing boric acid-stabilized aluminum acetate to form an aluminum borate powder, and sintering the powder to form a ceramic body.
Claims11
A process for producing an aluminum borate ceramic body comprising the steps of:
- (a) calcining substantially dry boric acid-stabilized aluminum acetate powder at a temperature between about 800.degree. C. and about 1600.degree. C. in the presence of oxygen for a time sufficient to convert at least about 80% of the powder to aluminum borate;
- (b) forming the calcined powder into a green body;
- and
- (c) sintering the green body at a temperature between about 1300.degree. C. and about 1800.degree. C. for a time sufficient to form a sintered aluminum borate ceramic body having a porosity of at least about 40%.
The process recited in claim 4 wherein said reducing step comprises milling said calcined powder in a ball mill.
A process for producing an aluminum borate ceramic body comprising the steps of:
- (a) calcining substantially dry boric acid-stabilized aluminum acetate powder at a temperature between about 500.degree. C. and about 1500.degree. C. in the presence of oxygen for a time sufficient to convert at least about 80 percent of the powder to aluminum borate;
- (b) reducing the particle size of the calcined powder;
- (c) forming the calcined powder into a green body;
- and
- (d) sintering the green body at a temperature to form about 1500.degree. C. and about 1700.degree. C. for a time sufficient to form a sintered aluminum borate ceramic body having a porosity greater than about 40 percent.
A ceramic body comprising aluminum borate having a porosity of from about 40 percent to about 60 percent, an average pore size of from about 0.5 to about 5 micrometers and a strength of at least about 50 MPa.
A filter comprising aluminum borate wherein said aluminum borate has a porosity of at least about 40 percent and an average pore size from about 2 to 3 micrometers.
Dependencies are inferred from the claim text.