A composition may be suitable for flowable refractory materials and include calcium aluminate cement, a filler, a plasticizer in the form of a copolymer comprising polyether side chains, and a retarder having at least one acid. An article may include such a composition.

Alumina-modified colloidal silica nanoparticles mitigate Alkali Silica Reaction (ASR) in cementitious compositions. Additives containing the nanoparticles are used in methods of reducing ASR in concrete and to form cementitious compositions. Cementitious products, such as concrete, made by these methods are described herein.

A full-fiber burner brick and a preparation method thereof, comprising mixing alumina crystal fiber and amorphous ceramic fiber with both of them being a combination of fibers of different lengths gradations, and moreover adding fine powder fillers of different particle size gradations and supplementing other additives. This enables the internal structure of the product more uniform, increases the bulk density of the product, and also benefits the suction filterability of fiber cotton blank, and is conducive to forming and improving the strength of the blank. The surface of the brick body is further provided with a coating, which can effectively protect the cotton fiber of the brick body fiber from harsh environments, improve its high temperature resistance, and help to extend the service life of the burner brick.

A full-fiber burner brick and a preparation method thereof, comprising mixing alumina crystal fiber and amorphous ceramic fiber with both of them being a combination of fibers of different lengths gradations, and moreover adding fine powder fillers of different particle size gradations and supplementing other additives. This enables the internal structure of the product more uniform, increases the bulk density of the product, and also benefits the suction filterability of fiber cotton blank, and is conducive to forming and improving the strength of the blank. The surface of the brick body is further provided with a coating, which can effectively protect the cotton fiber of the brick body fiber from harsh environments, improve its high temperature resistance, and help to extend the service life of the burner brick.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

Aspects of the invention include a method of producing a cement material comprising step of: first reacting a calcium-bearing starting material with a first acid to produce an aqueous first calcium salt; second reacting the aqueous first calcium salt with a second acid to produce a solid second calcium salt; wherein the second acid is different from the first acid and the second calcium salt is different from the first calcium salt; and thermally treating the second calcium salt to produce a first cement material. Preferably, but not necessarily, during the second reacting step, reaction between the first calcium salt and the second acid regenerates the first acid.

Hexavalent chromium-free slurry formulations which are suitable in the production of ceramic overlay coating systems are described. The formulations provide superior hot corrosion and heat oxidation protection for superalloy substrates. A basecoat slurry and topcoat slurry are provided. The basecoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3 with the incorporation of metal oxide particles. The topcoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3. Both of the basecoat slurry and the topcoat slurry are hexavalent chromium-free.

Hexavalent chromium-free slurry formulations which are suitable in the production of ceramic overlay coating systems are described. The formulations provide superior hot corrosion and heat oxidation protection for superalloy substrates. A basecoat slurry and topcoat slurry are provided. The basecoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3 with the incorporation of metal oxide particles. The topcoat slurry includes an aluminum phosphate based aqueous solution having a molar ratio of Al:PO.sub.4 higher than about 1:3. Both of the basecoat slurry and the topcoat slurry are hexavalent chromium-free.

A method for repairing damage on a non-friction surface of a carbon brake disc of an aircraft, includes: removal of a damaged region, cutting of a repair material, anti-oxidation modification of the repair material, bonding and curing, and high-temperature heat treatment. The anti-oxidation modification is performed on the repair material without affecting the mechanical properties of the repair material, which improves the anti-oxidation ability of the repair zone and avoids the preparation of an anti-oxidation coating. In this way, only the damage on the non-friction surface is repaired, and there is little effect on the mechanical properties, friction and wear properties and thermal conductivity of the carbon-carbon composite material.

A method for repairing damage on a non-friction surface of a carbon brake disc of an aircraft, includes: removal of a damaged region, cutting of a repair material, anti-oxidation modification of the repair material, bonding and curing, and high-temperature heat treatment. The anti-oxidation modification is performed on the repair material without affecting the mechanical properties of the repair material, which improves the anti-oxidation ability of the repair zone and avoids the preparation of an anti-oxidation coating. In this way, only the damage on the non-friction surface is repaired, and there is little effect on the mechanical properties, friction and wear properties and thermal conductivity of the carbon-carbon composite material.