Claims
- 1. A method of coating a powder selected from carbides, nitrides and/or carbonitrides with metal comprising Co and/or Ni, the coating being carried out during reaction of a solution containing a compound of the metal with a polyol while keeping the powder in a suspension including the solution, the polyol simultaneously functioning as a solvent and as a reducing agent and the polyol being present in excess relative to a stoichiometric amount of polyol to metal which forms an intermediate solid compound containing Co.sup.2+ and/or Ni.sup.2+ on the powder, the method comprising interrupting the reaction and separating an intermediate solid compound and the powder from the suspension before any oxidation by-products are formed in the solution followed by heat treating the intermediate solid compound so as to reduce the intermediate solid compound and provide a coating of the metal on the powder.
- 2. The method of claim 1, wherein the polyol comprises ethylene glycol.
- 3. The method of claim 1, wherein the metal comprises cobalt and the powder comprises WC.
- 4. The method of claim 1, wherein the intermediate solid compound comprises Co(OH).sub.2 or Ni(OH).sub.2 or mixture thereof.
- 5. The method of claim 1, wherein the reaction is carried out for less than six hours.
- 6. The method of claim 1, wherein the intermediate solid compound is precipitated from the solution by addition of NH.sub.3 or a hydroxide.
- 7. The method of claim 1, wherein the metal compound comprises a metal salt.
- 8. The method of claim 1, wherein the heat treatment is carried out in a hydrogen atmosphere.
- 9. The method of claim 1, wherein the heat treatment is carried out at a temperature of at least 300.degree. C. for at least one hour.
- 10. The method of claim 1, wherein the heat treatment is carried out at a temperature of less than 100.degree. C. for at least eight hours.
- 11. The method of claim 1, wherein the polyol separated from the suspension is reused by repeating the process with a different batch of powder.
- 12. The method of claim 1, wherein the excess of polyol is about 10 times the stoichiometric amount.
- 13. The method of claim 1, wherein the powder comprises (Ti,W)C and the excess of polyol is at least five times the stoichiometric amount.
Priority Claims (1)
Number |
Date |
Country |
Kind |
9503420 |
Sep 1995 |
SEX |
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Parent Case Info
This application is a continuation, of application Ser. No. 08/718,701, filed Sep. 27, 1996 now abandoned.
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Continuations (1)
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Number |
Date |
Country |
Parent |
718701 |
Sep 1996 |
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