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

TL;DR

This study combines high-pressure x-ray diffraction and ab initio calculations to investigate the structural stability and elastic properties of two families of ultra-incompressible bimetallic nitrides, revealing their high bulk modulus and potential hardness.

Contribution

It provides the first combined experimental and theoretical analysis of the high-pressure stability and elastic properties of these nitrides, identifying them as ultra-incompressible materials.

Findings

Nitrides remain stable up to 50 GPa

Bulk modulus exceeds 300 GPa

Predicted hardness comparable to gamma-Si3N4

Abstract

We have studied by means of high-pressure x-ray diffraction the structural stability of Ni2Mo3N, Co3Mo3N, and Fe3Mo3N. We also report ab initio computing modeling of the high-pressure properties of these compounds, Pd2Mo3N, and Pt2Mo3N. We have found that the nitrides remain stable in the ambient-pressure cubic 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 elastic constants have been calculated in order to quantify the stiffness of the investigated nitrides. We found that they should have a Vickers hardness similar to that of cubic spinel nitrides like gamma-Si3N4