The p–T–x-State Diagram of the Mg–Ni System

The analysis of equilibrium in the Mg–Ni system was carried out. Alloys on its basis are promising for use as sorbents and hydrogen storage (START). The conditions for the production and operation of such alloys imply strict control of the pressure of hydrogen. In this regard, phase equilibria in the Mg–Ni system must be considered not only depending on the composition and temperature, but also on the pressure of hydrogen. The most complete graphical representation of the equilibrium in the Mg–Ni system is given by a three-dimensional state diagram: pressure-temperature-composition (p–T–x), the projection of the three-phase equilibrium lines of this diagram on the pressure-temperature plane (p–T-state diagram), isobaric and isothermal sections of the diagram, diagram in pMg–T coordinates. Based on the analysis of experimental data on equilibrium in this system, the article presents the most important options of the listed types of diagrams. The presented diagram variants can be useful in optimizing the technology and operation of sorbents and START alloys of the Mg–Ni system.