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US 6,319,870 B1Granted
Fabrication of low thermal expansion, high strength cordierite structures
AssigneeCorning Incorporated
InventorsDouglas M. Beall, Martin J. Murtagh
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AssigneeCorning Incorporated
InventorsDouglas M. Beall, Martin J. Murtagh
Estimating the term…
The present invention is directed at sintered ceramic articles exhibiting a crystalline phase assemblage comprising, by weight, of 65-95% cordierite and 5-35% of a secondary phase selected from the group consisting of mullite, magnesium-aluminate spinel, and sapphirine and having a bulk analytical composition consisting essentially of about, by weight, 32-51% SiO2, 35-49% Al2O3, 7-16% MgO. Furthermore, the ceramic articles exhibit an effective strength of greater than about 3000, a CTE of less than about 15×10−7/° C., over the temperature range of 25° C., to 1000° C., and a total intrusion porosity, as measured by a Hg intrusion method, of at least 20%. This invention also relates to a method for producing a sintered ceramic article having the aforementioned cordierite and secondary minor phase mixture.
A ceramic article comprising a sintered phase composition, by weight of 65-95% cordierite and 5-35% of a secondary phase selected from the group consisting of mullite, magnesium-aluminate spinel, and sapphirine, a bulk analytical composition consisting essentially of about, by weight, 32-51% SiO2, 35-49% Al2O3, 7-16% MgO and exhibiting a total porosity of not less than about 20%, by volume, a coefficient of thermal expansion no greater than about 15.0×10−7/° C. over the temperature range of about 25° C. to about 1000° C., and an effective strength index greater than at least 3000.
A ceramic article comprising a sintered phase composition, by weight, of 65-95% cordierite and 5-35% of a secondary phase selected from the group consisting of mullite, magnesium-aluminate spinel, and sapphirine, a bulk analytical composition consisting essentially of about, by weight, 32-51% SiO2, 35-49% Al2O3, 7-16% MgO and falling within the ternary region designated by 1-2-3-4 of the ternary phase diagram of FIG. 1, and exhibiting a total porosity of not less than about 20%, by volume, and a coefficient of thermal expansion no greater than about 15.0×10−7/° C. over the temperature range of about 25° C. to about 1000° C., wherein the article exhibits an effective strength index greater than at least 3000.
A ceramic article comprising a sintered phase composition, by weight, of 65-95% cordierite and 5-35% of a secondary phase selected from the group consisting of mullite, magnesium-aluminate spinel, and sapphirine, having a bulk analytical composition consisting essentially of about, by weight, 32-51% SiO2, 35-49% Al2O3, 7-16% MgO and exhibiting a total porosity of not less than about 20%, by volume and a coefficient of thermal expansion no greater than about 15.0×10−7/° C. over the temperature range of about 25° C. to about 1000° C., the raw material mixture utilized to form the ceramic article comprising a delaminated kaolin, a highly reactive alumina having an average particle size of less than 8 μm in diameter, and a calcined platy talc, wherein the article exhibits an effective strength index greater than at least 3000.
Dependencies are inferred from the claim text.