Features of the Interaction and Phase Formation in the WC–Fe2O3–C System When Heated in Vacuum and in Argon

Abstract

Special features of the interactions and phase formations in carbide-oxide mixture WC 33.5 wt % Fe₂O₃ and in the WC–Fe₂O₃–C system when heated in vacuum and in argon have been studied. To add free carbon into carbide-oxide mixture, the K354 soot and saccharose, which dissociated when heated to high-clean carbon. It is established that at the absence of free carbon in the carbide-oxide system the active interaction between carbon of tungsten carbide and oxygen of iron oxide takes place that shows up in the weight loss of the samples. As a results there form the phase of the intermetallide Fe₇, W₆, the phase with a structure of the FeWO₄ and W. The addition of free carbon allows keeping tungsten carbide partly or completely and reducing iron from oxide. At the lack of free carbon some part of the tungsten carbide carbon starts to interact with oxygen and the Fe₃W₃C complex carbide forms in the system, at the excess of carbon the tungsten carbide retained and the bcc-iron forms. The heating in vacuum differs from the heating in argon by two indications: to remove the same amount of oxygen is spent more carbon than in heating in argon; the temperature of the active interaction of carbon with oxygen decreases. The largest (by 300°C) decrease of the temperature is observed when the saccharose is used as the source of free carbon.