초록 ▼

Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distanc

Crystalline silicon carbide wherein at least 90 weight percent of the silicon carbide is formed from a plurality of hexagonal crystal lattices wherein at least 80 weight percent of the crystals formed from the lattices contain at least a portion of opposing parallel base faces separated by a distance of from 0.5 to 20 microns. The crystals may be in the form of separate particles, e.g. separate platelets, or may comprise an intergrown structure. The crystalline silicon carbide of the invention is produced by heating a porous alpha silicon carbide precursor composition comprising silicon and carbon in intimate contact to a temperature of from 2100°C. to 2500°C. in a non-reactive atmosphere. The materials are high performance materials finding use in reinforcing, high temperature thermal insulating, improvement of thermal shock resistance, and modification of electrical properties.

대표청구항 ▼

A method of forming separate platelets of alpha silicon carbide comprising heating fine beta silicon carbide powder in an inert gas, nitrogen gas, or vacuum to a temperature of at least about 2150°C. and not greater than 2400°C. in the presence of vapor phase boron, aluminum, or mixtures thereof for

A method of forming separate platelets of alpha silicon carbide comprising heating fine beta silicon carbide powder in an inert gas, nitrogen gas, or vacuum to a temperature of at least about 2150°C. and not greater than 2400°C. in the presence of vapor phase boron, aluminum, or mixtures thereof for at least 15 minutes to effect conversion of substantially all of the beta silicon carbide powder into single crystal platelets of alpha silicon carbide.