Estimation of the Free Energy Changes of Nitride Formation of Rare Earth Metals in Liquid Iron Alloys

Abstract

From a standpoint of the fundamental study of steelmaking, the free energy changes of formation of the rare earth metal nitrides in liquid iron alloys were predicted by the use of the Miedema’s semi-empirical equations and some thermodynamic relations. The results estimated were discussed with some thermodynamic relationships for various nitrides, and the following results were obtained.
(1) It is expected that the rare earth metals form significantly stable nitrides in liquid iron alloys.
(2) For transition elements, the values of Δ\barG₁₈₇₃° change regularly with the group number of the periodic table. The rare earth metals also satisfy this relationship.
(3) The rare earth metals are assumed to have large negative values of ε_N^M and thus to have strong affinity for nitrogen.