Interaction and Phase Formation in the WC-Fe.sub.2O.sub.3-NiO-C System Heated in Vacuum and Argon

The interaction and phase formation in the WC-33 wt.% (80% Fe.sub.2O.sub.3 + 20% NiO) system with and without free carbon when heated in vacuum and in an argon atmosphere have been studied. Superfine soot and sucrose were used as free carbon. The powders pressed as pellets were heated by incremental temperature rise. In the absence of free carbon, the carbon contained in tungsten carbide and the oxygen contained in iron and nickel oxides actively interact in the carbide-oxide system, leading to weight loss of the samples. The intermetallic (Fe, Ni).sub.7W.sub.6 phase, (Fe, Ni)WO.sub.4 oxide, and tungsten form as a result. The addition of free carbon allows tungsten carbide to be retained partially or completely and iron and nickel to be reduced from oxides. If there is a lack of free carbon, some part of the carbon contained in tungsten carbide begins to interact with oxygen to form complex Me.sub.6C carbide in the system, the metal phase having fcc and bcc lattices. When heating proceeds in vacuum, more carbon is spent to remove the same amount of oxygen than in heating in an argon atmosphere, but temperature of active interaction between carbon and oxygen decreases.