Abstract: A ceramic honeycomb structure comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement comprised of inorganic fibers and a binding phase wherein the smaller honeycombs and fibers are bonded together by the binding phase which is comprised of an amorphous silicate, aluminate or alumino-silicate glass and the cement has at most about 5% by volume of other inorganic particles. The cement may be made in the absence of other inorganic and organic additives while achieving a shear thinning cement, for example, by mixing oppositely charged inorganic binders in water together so as to make a useful cement for applying to the smaller honeycombs to be cemented.

Abstract: A composite is formed by inserting a ceramic powder into a channel of a preform to form a ceramic powder filled preform. The ceramic powder has at least one reactive ceramic powder. The preform is a ceramic, ceramic-metal composite, metal or combination thereof that has walls that define a plurality of channels each channel having an opening at a surface of the preform. The ceramic powder filled preform is infiltrated with a molten metal to form the ceramic-metal body, which has at least one ceramic phase that is a reaction product of the reactive ceramic and molten infiltrated metal.

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.

Abstract: Highly porous acicular mullite bodies are prepared. A green body containing mullite precursors and a porogen is formed using a wet method. The green body is heated to sequentially remove any binder, the porogen and calcine it. The calcined body is mullitized. The process formed a calcined body that has excellent strength and can be handled easily. The mullitized body has very high porosity, small pores and has excellent fracture strength.

Abstract: A ceramic honeycomb structure comprised of at least two separate smaller ceramic honeycombs that have been adhered together by a cement comprised of inorganic fibers and a binding phase wherein the smaller honeycombs and fibers are bonded together by the binding phase which is comprised of an amorphous silicate, aluminate or alumino-silicate glass and the cement has at most about 5% by volume of other inorganic particles. The cement may be made in the absence of other inorganic and organic additives while achieving a shear thinning cement, for example, by mixing oppositely charged inorganic binders in water together so as to make a useful cement for applying to the smaller honeycombs to be cemented.

Abstract: A composite is formed by inserting a ceramic powder into a channel of a preform to form a ceramic powder filled preform. The ceramic powder has at least one reactive ceramic powder. The preform is a ceramic, ceramic-metal composite, metal or combination thereof that has walls that define a plurality of channels each channel having an opening at a surface of the preform. The ceramic powder filled preform is infiltrated with a molten metal to form the ceramic-metal body, which has at least one ceramic phase that is a reaction product of the reactive ceramic and molten infiltrated metal.