GB894056A - Ceramic fibre products and compositions and methods of making same - Google Patents

Abstract

A composition suitable for casting monolithic bodies, as a cement or a coating or a binder for ceramic fibres, comprises a hardened mixture of ceramic fibres with lengths 10 to 50 times their diameters and a dispersion of a colloidal inorganic oxide which forms at least 3% by weight of the dry mixture. Aluminium silicate fibres with diameters below 80 micron are preferred but other fibres such as silica, glass, mineral wool, asbestos, quartz are also used. Fillers such as graphite flour, micronized mica, powdered asbestos, clays, cement, glass, corundum, and quartz are also included and for low temperature applications organic fibres such as string, hemp and horse hair may be added. Metal powders such as Al, Mg and Pt or compounds such as Al2O3, ZrO2, BN or Si C may also be included in the composition. The oxide dispersion is preferably a concentrated aqueous dispension of silica the composition preferably containing 10%-15% silica by weight on a dry basis but for high density bodies the silica content may be over 50%. Other colloidal oxides such as ZrO2 or Al2O3 may also be used. The ceramic fibres are ball milled and screened to the desired length to diameter ratio, and mixed with the colloidal oxide or other constituents which may also include unground fibres of a greater length to diameter ratio. The mixture is cured at 200 DEG F or a temperature up to 2000 DEG F may be used when porosity is not important. The composition may be cast to form a monolithic body, used as a refractory coating on metals or non metals, or as a cement. Many examples of these different applications are described. The silica content of the cast bodies may be increased by impregnation with an aqueous dispension of colloidal silica. Specification 871,577 is referred to.