High porosity cordierite ceramic honeycomb article and method
AssigneeCorning Incorporated
InventorsWilliam Peter Addiego, Isabelle Marie Melscoet-Chauvel
Life of this patent
Estimating the term…
Abstract
The present invention provides materials and methods for the manufacture of high porosity ceramic exhaust filters employing relatively low amounts of pore formers, the filters combining efficient diesel particulate filtration with effective support for exhaust emissions control catalysts. Cordierite-forming ceramic batches comprising non-hydrated transition alumina powders of relatively large particle size provide high porosities with well-controlled pore sizes and with low filter thermal expansion coefficients and good mechanical strengths.
Claims12
A batch composition for the manufacture of a porous cordierite ceramic article comprising:
- a mixture of (i) oxide sources of magnesia, alumina and silica in proportions effective to yield a ceramic article incorporating a predominant cordierite (Mg2Al4Si5O18) crystal phase upon firing, (ii) one or more binders and lubricants, and (iii) a pore former in a proportion effective to develop a porosity of at least 50% by volume in the porous cordierite ceramic upon firing,
- the oxide source of alumina including at least one alumina powder having a mean particle size in the range of 15-50 μm and a surface area of at least 100 m2/g, and
- the pore former being present in amount less than 80% by weight calculated as a super-addition to the batch.
A method for making a porous cordierite ceramic article, comprising the steps of:
- compounding a batch comprising a mixture of (i) a pore former in an amount effective to develop a porosity in excess of 50% by volume in the porous ceramic article and (ii) oxide sources of magnesia, alumina, and silica in proportions effective to yield cordierite (Mg2Al4Si5O18) upon firing, the sources of alumina including a powdered transition alumina having a mean particle size of 15-50 μm and a surface area of at least 100 m2/g;
- forming the batch into a preform for a ceramic article;
- and
- firing the preform to form a porous cordierite ceramic article.
Dependencies are inferred from the claim text.