Method for making shaped silicon-silicon carbide refractories

Claim 1

A method for making a shaped silicon-silicon carbide refractory which consists essentially of (1) forming a putty by blending a mixture of (a) 100 parts of silicon powder, (b) 5 to 50 parts of particulated carbon, (c) 0 to 600 parts of silicon carbide, and (d) 4 to 15 parts of water, where said mixture is free of binder other than water, (a) and (b) have an average particle size of 1 to 200 microns, and (b) are carbon particles or fiber having a diameter of about 8 to 12 microns and an aspect ratio of L/D of from 2 to 8, (2) applying the putty of (1) onto the surface of a shaped supporting structure which has an expansion coefficient about equivalent to silicon carbide, or allows lateral expansion of in situ formed silicon-silicon carbide refractory, (3) heating the resulting applied putty-silicon carbide composition of (2) to a temperature of 1410° C. to 1600° C. to convert the applied putty to a shaped silicon-silicon carbide refractory, and (4) allowing the resulting composite of (3) to cool to ambient temperature and separating the resulting silicon-silicon carbide refractory from the supporting refractory structure.

Claim 2

A method for making a shaped silicon-silicon carbide refractory which consists essentially of (1) forming a putty by blending a mixture of (a) 100 parts of silicon powder, (b) 5 to 50 parts of particulated carbon, (c) 0 to 600 parts of silicon carbide, and (d) 4 to 15 parts of water, where said mixture is free of binder other than water, (a) and (b) have an average particle size of 1 to 200 microns, and (b) are carbon particles or fiber having a diameter of about 8 to 12 microns and an aspect ratio of L/D of from 2 to 8, (2) applying the putty of (1) onto the surface of a shaped supporting structure which has an expansion coefficient about equivalent to silicon carbide, or allows lateral expansion of in situ formed silicon-silicon carbide refractory, (3) heating the resulting applied putty-silicon carbide composition of (2) to a temperature of 1410° C. to 1600° C. to convert the applied putty to a shaped silicon-silicon carbide refractory, and (4) allowing the resulting composite of (3) to cool to ambient temperature and separating the resulting silicon-silicon carbide refractory from the supporting refractory structure.