The tendency of content gain of tungsten semi carbide (di-tungsten carbide) W2C after rapid sintering of compact ceramic structures on the base of tungsten carbide (monocarbide) WC from nano powders technology-based on electro consolidation under pressure is been considered. The issues of the genesis of W2C expansion in new technologies for producing nanostructured single-phase WC ceramics have been formulated and explained. The mechanisms of W2C carbide formation have been examined. By completely eliminating W2C, a single-phase tungsten monocarbide was obtained, with a fracture toughness of 10 MPa·m1/2 and a hardness of HV10=31GPa.