Abstract: Extremely hard, fine grained tungsten/carbon alloys are described which are produced by thermochemical deposition. The alloys consist primarily of a mixture of a substantially pure tungsten phase and at least one carbide phase wherein the carbide phase consists of W.sub.2 C or W.sub.3 C or a mixture of W.sub.2 C and W.sub.3 C. The disclosed tungsten/carbon alloys are free of columnar grains and consist essentially of extremely fine, equiaxial crystals. Also disclosed is a method of producing the disclosed material.

Abstract: A method for producing the disclosed material comprises introducing into a chemical vapor deposition (CVD) reactor a mixture of process gases comprised essentially of (1) tungsten hexafluoride, (2) a volatile oxygen- and hydrogen-containing organic compound, and (3) hydrogen; controlling the ratio of the tungsten hexafluoride to the oxygen- and hydrogen-containing organic compound within the CVD reactor so that the W/C atomic ratio is within the range of about 0.5 to about 15; controlling the reaction temperature so it is within the range of above about 300.degree. to less than about 650.degree. C.; controlling the total pressure within the range of about 1 Torr. to about 1,000 Torr.; and controlling the ratio of H.sub.2 to WF.sub.6 within the range of about 4 to about 20; to produce W and W.sub.2 C, W and W.sub.3 C, or W and W.sub.2 C and W.sub.3 C.

Abstract: The present invention is directed to a method for reducing process performance excursions during feed coal or process solvent changeover in a coal hydroliquefaction process by blending of feedstocks or solvents over time.