Fabrication of ultra-thinwall cordierite structures

A method of producing a ceramic body having cordierite as its primary phase, comprising the following steps:

• compounding and plasticizing a cordierite-forming raw material mixture having a chemical composition consisting essentially of about, by weight, 11 to 17% MgO, 33 to 41%, Al2O3 and, 46 to 53% SiO2;
• the mixture comprising the following:
• (a) a magnesium-source comprising a platy talc having a morphology index of greater than 0.8 and exhibiting a mean particle size of less than about 5 μm;
• (b) an Al2O3-forming source comprising an alumina having a mean particle size of less than about 5 μm selected from the group consisting of ∝-alumina, transition aluminas, aluminum oxide monohydroxide, or aluminum trihydrate;
• (c) one or more of the components of kaolin, calcined kaolin, and silica wherein the kaolin, if present, comprises delaminated kaolin having a mean particle size of less than about 2 μm and a surface area of greater than about 10 m2/g, the calcined kaolin, if present,:
• exhibits a mean particle size of less than about 211m, and silica, if present, exhibits mean particle size of less than about 2 μm;
• forming the plasticizable raw material mixture into a green ceramic body by extrusion through an extrusion die to at least partially align the raw materials in an orientation plane in such a manner that the shrinkage of the green ceramic body upon firing is anisotropic and is greater in direction perpendicular to the orientation plane than in an at least one other direction in the green ceramic body;
• drying the green body and thereafter firing the green body at a time and at a temperature between 1380° C. and 1450° C. to result in sintered ceramic body.