LAUSR

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 TiO$^{2}$ and a TiO$^{2}$─SiO$^{2}$ 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 H$^{2}$O through SiO$^{2}$.