High-pressure x-ray diffraction and ab initio study of Ni2Mo3N, Pd2Mo3N, Pt2Mo3N, Co3Mo3N, and Fe3Mo3N: Two families of ultra-incompressible bimetallic interstitial nitrides

摘要

We have studied by means of high-pressure x-ray diffraction the structuralstability of Ni2Mo3N, Co3Mo3N, and Fe3Mo3N. We also report ab initio computingmodeling of the high-pressure properties of these compounds, Pd2Mo3N, andPt2Mo3N. We have found that the nitrides remain stable in the ambient-pressurecubic structure at least up to 50 GPa and determined their equation of state.All of them have a bulk modulus larger than 300 GPa. Single-crystal elasticconstants have been calculated in order to quantify the stiffness of theinvestigated nitrides. We found that they should have a Vickers hardnesssimilar to that of cubic spinel nitrides like gamma-Si3N4