2017 Volume 31 Pages 1-5
A functionally graded material (FGMs) MoSi2/Mo was adopted for oxidation resistance coating of γ-TiAl. The MoSi2 coating was produced by dipping Mo plates in the molten salt. The obtained MoSi2 coating layer resulted was approximately 60 μm in thickness. The oxidation resistance of MoSi2/Mo was examined at 1323-1423 K for 3-400 h in still air, as a criterion for the lifetime of MoSi2/Mo/γ-TiAl FGMs. The oxidation at 1423 K for 30 h in still air caused Si to diffuse into Mo without cracks or voids at MoSi2/Mo interlayer. The MoSi2 activation energy of volume diffusion was estimated as 523 ± 75 kJ/mol, which was consistent with the available data. The lifetime of the MoSi2 coating was approximately five times larger than that of a NbSi2 coating under the same condition. An oxidation-resistant MoSi2/Mo FGMs coating has a longer lifetime than an NbSi2/Nb coating for γ-TiAl.
