Refractory metal ceramics and methods of making thereof

A method comprising:

• providing a precursor mixture of particles of a refractory metal or a refractory metal hydride and an organic compound;
• heating the precursor mixture in an inert atmosphere at a pressure greater than atmospheric pressure and at a temperature that causes decomposition or reaction of the refractory-metal or the refractory metal hydride to form a metal nanoparticle composition comprising refractory-metal nanoparticles;
• and
• heating the metal nanoparticle composition in an inert atmosphere, argon, or nitrogen at a temperature that causes formation of a ceramic comprising nanoparticles of a refractory-metal carbide or a refractory-metal nitride in a carbonaceous matrix;
• wherein the organic compound has a char yield of at least 60% by weight when heated at the pressure greater than atmospheric pressure.

A method comprising:

• combining particles of a refractory metal or a refractory metal hydride with an organic compound having a char yield of at least 60% by weight to form a precursor mixture;
• heating the precursor mixture in an inert atmosphere at a temperature that causes decomposition or reaction of the refractory-metal compound or particles to form refractory-metal nanoparticles to form a metal nanoparticle composition;
• heating the metal nanoparticle composition in an inert atmosphere, argon, or nitrogen at a temperature that causes formation of a ceramic comprising nanoparticles of a refractory-metal carbide or a refractory-metal nitride in a carbonaceous matrix;
• and
• heating the ceramic in an oxygen-containing atmosphere to form an oxide of the refractory metal on the surface of the ceramic.