Effect of Water Vapor on the Oxidation Behavior of the Eutectic High‐Temperature Alloy Mo‐20Si‐52.8Ti

Herein, the effect of water vapor on the oxidation resistance of the alloy Mo‐20Si‐52.8Ti (at%) is investigated. The alloy is oxidized in dry, wet, as well as in in situ changing atmospheres at 1100 °C. The oxidation kinetics changes from nearly parabolic to linear if water vapor is present in oxidizing atmosphere. Under all conditions, the oxide scales consist of an outer TiO₂ and a TiO₂SiO₂ duplex layer underneath. In wet atmosphere, the thicknesses of the two regions substantially increase indicating a severe ingress of water vapor. The inferior oxidation resistance in wet environment is primarily rationalized by the fast diffusion of H₂O through SiO₂.