Abstract: A porous mullite composition is made by forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.

Abstract: A porous mullite composition is made by forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.

Abstract: An organic additive is removed from a ceramic honeycomb by an improved method by contacting each end of the extruded honeycomb with a member that has a gas permeability no greater than the outer wall, the member essentially covering the ends and heating the honeycomb to a temperature sufficient to remove the organic additive.

Abstract: A porous mullite composition is made by Forming a mixture of one or more precursor compounds having the elements present in mullite (e.g., clay, alumina, silica) and a property enhancing compound. The property enhancing compound is a compound having an element selected from the group consisting of Mg, Ca, Fe, Na, K, Ce, Pr, Nd, Sm, Eu, Gd, Th, Dy, Ho, Er, Tm, Yb, Lu, B, Y, Sc, La and combination thereof. The mixture is shaped and to form a porous green shape which is heated under an atmosphere having a fluorine containing gas to a temperature sufficient to form a mullite composition comprised substantially of acicular mullite grains that are essentially chemically bound.

Abstract: A method of forming a porous mullite composition of acicular mullite grains having improved properties is described, where the mullite is formed at some time in the presence of a fluorine containing gas. For example, it has been discovered that improved properties may result from heating the mullite to a high temperature in an atmosphere selected from the group consisting of water vapor, oxygen, an inert gas or mixtures thereof or forming the mullite composition from precursors having an AL/Si ratio of at most 2.95.