Diffusion Paths for Interstitial Impurities in Different Polymorphic Modifications of Niobium Silicide Nb₅Si₃

Structural models of the α, β, and γ modifications of Nb₅Si₃ silicides, which are used as a reinforcing phase in composites obtained in situ based on the Nb‒Si system, have been constructed by computer simulation methods. A geometric analysis of unit cells is performed using the H-poisk program to estimate the voids existing in the structures. The results of measuring the number of voids and their sizes are reported. A conclusion about possible diffusion paths of interstitial boron, carbon, nitrogen and oxygen atoms is drawn based on the calculation results, and the solubility of these impurities in the structure of each Nb₅Si₃ modification is estimated.