Regularities of formation of lines of monovariant phase equilibria in the binary Cr-Fe system

Abstract

This paper shows the applicability of the Bjerrum-Guggenheim osmotic coefficient for calculating the features of the crystallization fields of the Cr-Fe binary system. To determine the applicability of the Bjerrum-Guggenheim osmotic coefficient, the dissolution heats and activity coefficients of chromium and iron in a Cr-Fe melt with an atomic content of chromium in the range of 0-100% were calculated on the basis of the Cr-Fe system state diagram, in addition to the previously performed calculations, at temperatures from 2103 K to 1780 K (on the chromium side) and from 1812 K to 1780 K (on the iron side). The calculation predicts positive deviations of the Cr-Fe system from Raoul's law, as well as in the case of the osmotic coefficient, which confirms the reliability and adequacy of the approach from the perspective of the Bjerrum-Guggenheim concept when extracting information from state diagrams. It should be noted that calculations based on regular solutions can mainly be used for systems that do not form a series of solid solutions, which is also one of the disadvantages of this method.