The present invention relates to a porous aggregate, comprising Al.sub.2O.sub.3, SiO.sub.2 and optionally Fe.sub.2O.sub.3, having a d.sub.50 of equivalent pore diameter between 1 ?m or more and 50 ?m or below and a total porosity between 20% and 60%, for use in the formation of monolithic refractories. Also part of the invention is a method of formation for said aggregates, their use in the formation of monolithic refractories and monolithic refractories comprising such aggregates.

A mullite-containing sintered body according to the present invention contains mullite and at least one selected from the group consisting of silicon nitride, silicon oxynitride, and sialon. It is preferable that the mullite-containing sintered body have a thermal expansion coefficient of less than 4.3 ppm/ C. at 40 C. to 400 C., an open porosity of 0.5% or less, and an average grain size of 1.5 m or less.

A ceramic honeycomb structure comprising large numbers of cells partitioned by porous cell walls, the cell walls having (a) porosity of 50-80%, and when measured by mercury porosimetry, (b) a median pore diameter being 25-50 m, (c) (i) a cumulative pore volume in a pore diameter range of 20 m or less being 25% or less of the total pore volume, (ii) a cumulative pore volume in a pore diameter range of more than 20 m and 50 m or less being 50% or more of the total pore volume, and (iii) a cumulative pore volume in a pore diameter range of more than 50 m being 12% or more of the total pore volume.

The invention relates to a use of a refractory material for contact with a liquid metal or alloy, a method for the manufacture of an article made of said material, the article so obtained and a method of use of said article. The refractory material is obtained from a mixture comprising from 0 wt. % to 40 wt. % of aggregates and/or fmes of zirconia; from 10 wt. % to 50 wt. % of aggregates and/or fmes of alumina; and from 20 wt. % to 50 wt. % of aggregates and/or fines of mullite; formed into a desired shape and then subjected to a heating treatment at a temperature of from 750 C. to 1500 C.

The present invention relates to a low-temperature co-fired ceramic powder and a preparation method and application thereof. The material composition of the low-temperature co-fired ceramic powder is xRO-yM.sub.2O.sub.3-zXO.sub.2, where R is at least one of Mg, Ca, Ba, Zn, Cu, and Pb, M is at least one of B, Al, Co, In, Bi, Nd, Sm, and La, X is at least one of Si, Ge, Sn, Ti, Zr, and Hf, 0x85 wt %, 15 wt %y90 wt %, 10 wt %z85 wt %, and x+y+z=1; and the low-temperature co-fired ceramic powder is obtained by high-temperature melting, quenching, and recrystallization treatment. The temperature of high-temperature melting is 1,200 C. to 1,600 C., and the temperature of recrystallization treatment is 500 C. to 900 C.

A refractory object can include at least approximately 10 wt % Al.sub.2O.sub.3 and at least approximately 1 wt % SiO.sub.2. In an embodiment, the refractory object can include an additive. In a particular embodiment, the additive can include TiO.sub.2, Y.sub.2O.sub.3, SrO, BaO, CaO, Ta.sub.2O.sub.5, Fe.sub.2O.sub.3, ZnO, or MgO. The refractory object can include at least approximately 3 wt % of the additive. In an additional embodiment, the refractory object can include no greater than approximately 8 wt % of the additive. In a further embodiment, the creep rate of the refractory object can be at least approximately 110.sup.6 h.sup.1. In another embodiment, the creep rate of the refractory object can be no greater than approximately 510.sup.5 h.sup.1. In an illustrative embodiment, the refractory object can include a glass overflow trough or a forming block.

A ceramic precursor composition suitable for sintering form a ceramic material or structure therefrom, for example, a ceramic honeycomb structure, a ceramic material or structure, for example, a ceramic honeycomb structure obtainable by sintering said ceramic precursor composition, a method for preparing said ceramic precursor composition and ceramic material or structure, for example, ceramic honeycomb structure, a diesel particulate filter comprising said ceramic structure, a selective diesel particulate filter comprising said ceramic structure, a gasoline particulate filter comprising said ceramic structure, a vehicle comprising said diesel particulate filter, selective diesel particulate filter or gasoline particulate filter, and a SCR catalyst system comprising said ceramic material or structure.

Composite ceramic materials are disclosed herein which comprise two or more crystalline phases, wherein a first crystalline phase comprises a first refractory material having a first melting point, and a second crystalline phase comprises a second refractory material having a second melting point which is lower than the first melting point, and the second crystalline phase comprises large domain sizes of the second refractory material. Articles comprising such a composite ceramic material, such as honeycomb bodies, catalytic substrates, and particulate filters, are also disclosed herein, in addition to methods of manufacture thereof.

Disclosed are ceramic bodies comprised of composite cordierite-mullite-aluminum magnesium titanate (CMAT) ceramic compositions having high cordierite-to-mullite ratio and methods for the manufacture of same.

The present disclosure generally relates to a ceramic core comprising predominantly mullite, which is derived from a precursor comprising alumina particles and siloxane binders. Free silica is present in the ceramic body, but is largely unavailable for reaction with metal alloys used in investment casting. Methods of making cast metal articles are also disclosed.