A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 μm in a longitudinal direction.

A circumferential coating material to be applied to a circumferential surface of a honeycomb structure made of ceramics formed by extrusion, the circumferential coating material including a ceramic raw material that forms a circumferential coating layer, wherein the ceramic raw material contains: a ceramic mixture of first ceramic particles having particulate shapes, and second ceramic particles having particulate shapes and an average particle diameter different from an average particle diameter of the first ceramic particles; and a fiber material having an elongated strip-like shape, wherein the ceramic mixture has particle size distribution including at least two local maximum values, and the fiber material has an average fiber length ranging from 30 to 100 μm in a longitudinal direction.

A composite material containing a matrix and a fibrous reinforcement, in particular a textile embedded in the matrix. The matrix includes a geopolymer of the poly(phospho-sialate) type having the following formula I: (1) (—P—O—Si—O—Al—O—).sub.n in which n is greater than 2. The matrix further includes zirconium covalently bonded to the matrix, especially in the —ZrO form and/or in the —O—Zr—O form. The matrix has a melting temperature greater than 700° C., especially equal to or greater than 1200° C.

A composite material containing a matrix and a fibrous reinforcement, in particular a textile embedded in the matrix. The matrix includes a geopolymer of the poly(phospho-sialate) type having the following formula I: (1) (—P—O—Si—O—Al—O—).sub.n in which n is greater than 2. The matrix further includes zirconium covalently bonded to the matrix, especially in the —ZrO form and/or in the —O—Zr—O form. The matrix has a melting temperature greater than 700° C., especially equal to or greater than 1200° C.

A method for producing a porous body, comprising a raw-material mixing step of mixing talc having an average particle size of 1 μm or more and 18 μm or less, alumina, an auxiliary raw material containing a material that undergoes a eutectic reaction with talc and being prepared in an amount so as to satisfy a weight ratio of 0.5% or more and 1.5% or less by weight relative to the talc, and a pore-forming agent, to provide green body, and a molding and firing step of molding the green body to provide a compact and firing this compact at a firing temperature of 1350° C. to 1440° C.

A method for producing a porous body, comprising a raw-material mixing step of mixing talc having an average particle size of 1 μm or more and 18 μm or less, alumina, an auxiliary raw material containing a material that undergoes a eutectic reaction with talc and being prepared in an amount so as to satisfy a weight ratio of 0.5% or more and 1.5% or less by weight relative to the talc, and a pore-forming agent, to provide green body, and a molding and firing step of molding the green body to provide a compact and firing this compact at a firing temperature of 1350° C. to 1440° C.

A ceramic honeycomb body having a skin that does not block partial cells extending from an inlet face to an outlet face at an outer periphery portion of the body. A method of making the ceramic honeycomb body having the skin includes disposing a sheet on an outer peripheral wall of a honeycomb core having an outer surface spaced apart from interiors of the partial cells and skinning the body having the sheet disposed thereon. Subsequent curing in the method bonds the skin to cell walls of the body spaced apart from interiors of the partial cells.

A ceramic honeycomb body having a skin that does not block partial cells extending from an inlet face to an outlet face at an outer periphery portion of the body. A method of making the ceramic honeycomb body having the skin includes disposing a sheet on an outer peripheral wall of a honeycomb core having an outer surface spaced apart from interiors of the partial cells and skinning the body having the sheet disposed thereon. Subsequent curing in the method bonds the skin to cell walls of the body spaced apart from interiors of the partial cells.

A method of forming a sand control device comprising: infusing a curable inorganic mixture with a degradable material configured to disintegrate upon exposure to an external stimuli; forming the curable inorganic mixture infused with the degradable material about a tubular; and curing the curable inorganic mixture infused with the degradable material.

A filter including a plurality of pillar-shaped honeycomb structure segments made of porous ceramics, side faces of the segments being bonded together via a bonding material, wherein each of the pillar-shaped honeycomb structure segments includes an outer peripheral side wall, and partition walls partitioning a plurality of cells extending from a first end face to a second end face, and in each of the pillar-shaped honeycomb structure segments, an average porosity of the outer peripheral side wall is lower than that of the partition walls.