The oxidation of a directionally solidified cobalt-tungsten eutectic alloy

A study of the oxidation of directionally solidified Co-W alloys were performed at 750, 900, and 1050°C. The study involved a comparison of the oxidation behavior of directionally solidified and as-cast alloys along with the oxidation behavior of the pure components. The study incorporated both thermogravimetric kinetic measurements and morphological studies of the oxides as a function of both temperature and time. Differences were noticed in both the oxidation rate and the oxide morphology and were attributed to differences in alloy microstructure. The directionally solidified Co-W alloy was found to be more spall resistant but also oxidized more rapidly than the conventionally as-cast alloy. Both alloys were more oxidation resistant than the pure components.