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Process for preparing fine powders of aluminum nitride

  • US 5,151,260 A
  • Filed: 12/19/1990
  • Issued: 09/29/1992
  • Est. Priority Date: 12/21/1989
  • Status: Expired due to Fees
First Claim
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1. Process for preparing fine powders of aluminum nitride, by starting from an aqueous solution of an inorganic aluminum salt, wherein said process comprises:

  • (a) removing the anion of the inorganic aluminum salt at least partially by heating, with a colloidal solution of an aluminum compound being obtained;

    (b) dispersing carbon powder in said colloidal solution, with a suspension of an aluminum compound and carbon being obtained;

    (c) mixing said suspension with a carbohydrate, with a suspension being obtained of an aluminum compound and carbon in a solution which contains the carbohydrate;

    (d) adding the suspension obtained from the (c) step to an alkaline solution, with spherical bodies being obtained which contain aluminum hydroxide and carbon;

    (e) reducing and nitriding said spherical bodies carbothermally at a temperature of from 1350°

    to 1650°

    C. for a time of from 1 to 24 hours, so that powders containing aluminum nitride are obtained; and

    (f) removing carbon from said powders by a calcination step carried out at a temperature of from 600°

    to 700°

    C., for a time of from 1 to 7 hours, under an oxygen-containing atmosphere.

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