The effect of Al and Cr elements on the oxidation resistance of MoSi2 via first-principles calculation

Publication date: Available online 22 February 2019Source: Progress in Natural Science: Materials InternationalAuthor(s): Liwu Jiang, Meiling Wu, Peng Shi, Chuanhui ZhangAbstractThe properties of structure, energy and oxidation resistance of interstitial and substitutable MoSi2 systems have been investigated using the density functional theory. The calculated lattice constants for pristine MoSi2 confirm the early experimental results. In the interstitial MoSi2, the impurity energy of O atom was computed for the stable interstitial site in the systems. The results reveal that the O atom prefers to occupy the Oct2 site with the lowest impurity energy. In the substitution MoSi2, the Si sites tend to be substituted with Al and Cr atoms, whereas, Mo sites do not behave like the Si sites. The co-substitution of Al/Cr atoms and the direction of the O diffusion in MoSi2 have been analyzed as well. The results from electronic structural analysis indicate that the Si-O bond is the main factor to inhibit the diffusion of O, and the alloying elements of Al and Cr contribute to the oxidation resistance of MoSi2.Graphical abstract
Source: Progress in Natural Science: Materials International - Category: Materials Science Source Type: research