Process of producing aluminum and titanium nitrides

A process for producing a nitride of a metal selected from the group consisting of aluminum and titanium in the form of fine particles selected from the group consisting of powder and whiskers by reaction of the corresponding metal oxide with carbon at high temperature in the presence of nitrogen, wherein the process comprises:

• forming a uniform dispersion of microfine particles of said oxide in a polymer having the following characteristics:
• (a) a molecular weight of at least 10,000 and a long chain structure of at least 200 monomer units, (b) a carbon yield of at least 30% by weight, and (c) a chemical structure which is infusible or which is capable of being rendered infusible, said dispersion being formed by dissolving the polymer in a solvent, adding the oxide particles to the resulting solution, agitating the solution to disperse the particles uniformly, and removing the solvent by adding the solution to a bath containing a non-solvent for the polymer and the metal oxide which non-solvent is miscible with the solvent such that the polymer is coagulated and such that said particles are substantially unagglomerated and separated from each other by said polymer;
• while removing said solvent, forming the dispersion into bodies shaped in such a way that substantially none of the oxide particles within any one of said bodies is more than about 2.5 mm from an external surface of said one body;
• loosely packing said bodies into a reactor in such a way that at least 40% of the volume of the packed bodies comprises voids between the bodies;
• carbonizing the resulting bodies in said reactor in non-oxidizing atmosphere in order to convert the polymer to carbon;
• and heating the carbonized product in said reactor at high temperature in a non-oxidizing atmosphere containing nitrogen or a compound which decomposes to form nitrogen at said high temperature in order to form said nitride particles.