Emissivity of the Period V Metallic Elements of the Periodic Table during Melting: Correlation with Thermophysical Properties

Abstract—The emissivity of the period V elements of the periodic system during melting and its relationship with thermophysical characteristics, such as electrical resistivity and thermal expansion coefficient, are studied. Emissivity is an important thermophysical characteristic, which determines the behavior of materials during high-temperature processes. However, systematic data on its values for various metallic elements are lacking, making it difficult to predict the thermal characteristics of new materials. We use our experimental data obtained by the absolute radiation method in an inert gas atmosphere and experimental results from open sources. Calculations are performed using Foote’s approximation, which describes the relationship between emissivity and electrical resistivity. The obtained experimental and calculated data are shown to be in good agreement. The emissivity is found to undergo abrupt changes during phase transitions. Transition metals (Zr, Nb, Mo, Tc, Ru) exhibit relatively stable behavior, and post-transition elements (Ag, Cd, Sb, Te) exhibit significant jumps. An inverse correlation between the emissivity of a liquid phase on melting and the thermal expansion coefficient has been revealed. The results obtained can be used in the design of materials for the aerospace and energy industries, the refinement of thermophysical property databases, and the development of coatings with controlled emissivity. The laws of emissivity changes can be used to predict the thermal characteristics of elements without the need for expensive experiments.