Claims
- 1. An extruded fired cordierite ceramic article having an average linear coefficient of thermal expansion (25-800° C.) below about 5.0×10−7° C.−1, a total porosity between the range of 20% to about 30%, exhibiting a pore size distribution such that at least about 86% of pores exhibit a pore size of less than about 2 μm.
- 2. The fired cordierite ceramic article according to claim 1 wherein the article exhibits interconnected pore structure with the pores exhibiting a generally elongated shape and predominately oriented with their long axis in the plane of the webs.
- 3. The fired cordierite ceramic article according to claim 1 wherein the article exhibits an MOR strength of greater than about 300 psi.
- 4. The fired cordierite ceramic article according to claim 1 wherein the article exhibits an A-axis crush strength of greater than 3640 psi.
- 5. The fired cordierite ceramic article according to claim 1 wherein the article exhibits a total porosity between the range of 23-30%.
- 6. The fired cordierite ceramic article according to claim 1 wherein the article exhibits a pore size distribution such that at least about 90% of pores exhibit a pore size of less than about 2 μm.
- 7. A method for making an extruded fired cordierite honeycomb article comprising the steps of:
(a) compounding and plasticizing a cordierite-forming inorganic powder batch comprising a talc having median particle size less than about 2 μm, at least 4% by weight of the inorganic powder batch mixture consisting of a dispersible Al2O3-forming source having a specific surface area in excess of 50 m2/g, and one or more components selected from the group of kaolin, calcined kaolin, silica, and corundum, each having a median particle sizes less than 5 μm; (b) forming the plasticized powder batch into a green honeycomb by extrusion through a honeycomb extrusion die; and, (c) firing the green honeycomb to a temperature and for a time sufficient to convert the green honeycomb into a crystallized cordierite ceramic article having an average linear coefficient of thermal expansion (25-800° C.) below about 5.0×10 −7° C., and exhibiting a total porosity between the range of 20% to about 30%, and a pore size distribution such that at least about 86% of pores exhibit a pore size of less than about 2 μm.
- 7. The method according to claim 7 wherein the talc comprises a platy talc having a morphology index greater than about 0.75.
- 8. The method according to claim 7 wherein the dispersible Al2O3-forming source exhibits a specific surface area in excess of 100 m2/g.
- 9. The method according to claim 7 wherein the dispersible Al2O3-forming source is boehmite having an average particle size greater than about 150 m2/g.
- 10. The method according to claim 7 wherein the crystallized cordierite ceramic article exhibits an interconnected pore structure with the pores exhibiting a generally elongated shape and predominately oriented with their long axis in the plane of the webs, an MOR strength of greater than about 300 psi, and an A-axis crush strength of greater than 3640 psi.
- 11. An extrudable mixture for use in preparing a substrate having cordierite as its primary phase and having an inorganic raw material mixture having a chemical composition, in percent by weight, of 11 to 17% MgO, 33 to 41%, Al2O3 and, 46 to 53% SiO2, the inorganic raw material mixture comprising a talc having median particle size less than about 2 μm, at least 4% by weight of the inorganic powder batch mixture consisting of a dispersible Al2O3-forming source having a specific surface area in excess of 50 m2/g, and one or more components selected from the group of kaolin, calcined kaolin, silica, and corundum, each having a median particle sizes less than 5 μm.
- 12. The extrudable mixture according to claim 11 wherein the talc is a platy talc having a morphology index greater than about 0.75.
- 13. The method according to claim 11 wherein the dispersible Al2O3-forming source exhibits a specific surface area in excess of 100 m2/g.
- 14. The extrudable mixture according to claim 11 wherein the dispersible Al2O3-forming source is boehmite having a average particle size greater than about 150 m2/g.
Parent Case Info
[0001] This application claims the benefit of U.S. Provisional Application Nos. 60/138,930, filed Jun. 11, 1999 and 60/174,010 filed Dec. 30, 1999, entitled “Low Expansion, High Porosity, High Strength Cordierite Body and Method”, by Beall et al.
Provisional Applications (2)
|
Number |
Date |
Country |
|
60138930 |
Jun 1999 |
US |
|
60174010 |
Dec 1999 |
US |
Divisions (1)
|
Number |
Date |
Country |
Parent |
09590106 |
Jun 2000 |
US |
Child |
10174345 |
Jun 2002 |
US |