METHOD FOR FORMING BINDER-FREE REFRACTORY CARBIDE, NITRIDE AND BORIDE COATINGS WITH A CONTROLLED POROSITY

摘要

The present invention is directed to methods for formation of refractory carbide, nitride, and boride coatings without use of a binding agent. The present invention is directed to methods of creating refractory coatings with controlled porosity. Refractory coatings can be formed from refractory metal, metal oxide, or metal/metal oxide composite refractory coating precursor of the 9 refractory metals encompassed by groups 4-6 and periods 4-6 of the periodic table; non-metallic elements (e.g. Si & B) and their oxides (i.e. SiO2 & B2O3) are also pertinent. The conversion of the refractory coating precursor to refractory carbide, nitride or boride is achieved via carburization, nitridization, or boridization in the presence of carbon-containing (e.g. CH4), nitrogen containing (e.g. NH3), and boron-containing (e.g. B2H6) gaseous species. Any known technique of applying the refractory coating precursor can be used. The porosity of resultant refractory coatings is controlled through compositional manipulation of composite refractory coating precursors.