Thermodynamic Calculation of Fe–N and Fe–Ga Melting Diagrams at Pressures from 0.1 MPa to 7 GPa

Abstract

This paper presents results of melting-diagrams’ calculations for the Fe–N and Fe–Ga systems at atmospheric pressure (0.1 MPa) and at high pressures (3, 5 and 7 GPa). Thermodynamic calculations are performed within the models of phenomenological thermodynamics. As shown, the increase of pressure results in destabilization of high-temperature b.c.c.-Fe modification in Fe–N system and stabilization of Fe4N equilibrium with the liquid phase. In Fe–Ga system, the intermetallic compounds Fe3Ga, Fe6Ga5, Fe3Ga4, and FeGa3 retain their stability up to pressure of 7 GPa. The stabilization of Fe4N equilibrium with the liquid phase at high pressures indicates that the Fe4N can be a competing phase in the gallium-nitride crystallization from the Fe–Ga–N system melt.

Keywords

• fe–n and fe–ga diagrams
• high pressures
• thermodynamic calculations
• thermocalc