Sintered silicon carbide and method of making
AssigneeGeneral Electric Company
InventorSvante Prochazka
Life of this patent
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Abstract
A method for refined silicon carbide powder comprises attrition milling silicon carbide material in a liquid medium with a milling media to obtain refined silicon carbide particles having a specific surface area of at least 15 m.sup.2 /g, and preferably 20 m.sup.2 /g, with a median particle size of less than 0.5 microns, and preferably 0.25 microns. The invention includes the finished powder.
Claims8
A method for making refined silicon carbide powder comprising:
- attrition milling silicon carbide material, having an average particle size before milling of greater than or equal to 1 micron, in a presence of a liquid medium and a milling media, said liquid medium is an organic solvent, water, or mixtures thereof and, said milling media selected from the group consisting of dense sintered silicon carbide beads of about 1-2 millimeter size, fused boron carbide grit-14+32mesh size, and mixtures thereof, for a sufficient amount of time to obtain refined silicon carbide particles with a surface area greater than 15 m.sup.2 /g and a median silicon carbide particle size less than 0.5 microns, and where less than 0.1 percent of the refined silicon carbide particles are greater than 1.5 microns.
A refined silicon carbide powder having a surface area greater than 15 m.sup.2 /g and a median silicon carbide particle size less than 0.5 microns, where less than 0.1 percent of the refined silicon carbide particles are greater than 1.5 microns.
A method for making an improved silicon carbide fiber comprising the steps of:
- attrition milling silicon carbide material at a pH of about 10, having an average particle size before milling of greater than or equal to 1 micron, in a presence of a liquid medium and a milling media, said liquid medium is an organic solvent, water, or mixtures thereof and, said milling media selected from the group consisting of dense sintered silicon carbide beads of about 1-2 millimeter size, fused boron carbide grit-14+32mesh size, and mixtures thereof, for a sufficient amount of time to obtain refined silicon carbide particles with a surface area greater than 15 m.sup.2 /g and a median silicon carbide particle size less than 0.5 microns, and where less than 0.1 percent of the refined silicon carbide particles are greater than 1.5 microns;
- forming a silicon carbide fiber with said refined silicon carbide particles;
- and
- sintering the silicon carbide fiber at a reduced sintering temperature to obtain a fine grained dense microstructure having a density greater than or equal to 2.98 g/cc.
Dependencies are inferred from the claim text.