Energetics of binary iron nitrides

Abstract

High-temperature solution calorimetry in molten sodium molybdate 3Na2O·4MoO3 was used to determine the energetics of formation of a series of binary iron nitrides: γ'-Fe4N, ε-Fe3N(1+y) (y = 0, 0.10, 0.22, 0.30, 0.33), ζ-Fe2N and γ'-FeN0.91. The linear relation ΔH(f)°(FeN(x))= -65.23x + 13.48 kJ mol-1 was found between the enthalpies of formation from the elements at 298 K of iron nitrides FeN(x) and their nitrogen content x. Using this linear approximation, the enthalpy of formation of α'-Fe16N2 has been estimated to ΔH(f)°(Fe16N2)= 85.2 ± 46.8 kJ mol-1. (C) 2000 Editions scientifiques et medicales Elsevier SAS.