Claims
- 1. 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.
- 2. A method according to claim 1 where the liquid medium is a solvent and is selected from the group consisting of tertiary butyl alcohol, p-dimethylxylene, carbon tetrachloride, cyclohexane, methyl isobutyl ketone, and mixtures thereof.
- 3. A method according to claim 2 where the solvent is about 10-15 weight percent methyl isobutyl ketone and a balance tertiary butyl alcohol.
- 4. A method according to claim 1 where the silicon carbide particles have a surface area greater than 20 m.sup.2 /g and a median silicon carbide particle size less than or equal to 0.25 microns.
- 5. A method according to claim 1 where the milling is performed at a pH of about 10.
- 6. 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.
- 7. A refined silicon carbide powder according to claim 6 having a surface area greater than 20 m.sup.2 /g and a median particle size of 0.25 microns.
- 8. 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.
Parent Case Info
This application is a Continuation of application Ser. No. 08/538,148 filed Oct. 2, 1995, now abandoned.
Government Interests
This invention was made with government support under Contract No. NAS3-26385. The government may have certain rights to the invention.
US Referenced Citations (8)
Foreign Referenced Citations (1)
Number |
Date |
Country |
289 751 A5 |
May 1991 |
DDX |
Non-Patent Literature Citations (2)
Entry |
"Silicon Oxycarbide Glasses: Part I. Preparation and Chemistry", GM Renlund, S. Prochazka, RH Doremus, J. Mater. Res., vol. 6, No. 12, Dec. 1991, pp. 2716-2722. |
"Silicon Oxycarbide Glasses: Part II. Structure and Properties", GM Renlund, S. Prochazka, RH Doremus, J. Mater. Res., vol. 6, No. 12, Dec. 1991, pp. 2723-2733. |
Continuations (1)
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Number |
Date |
Country |
Parent |
538148 |
Oct 1995 |
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