Metastable — Stable Structural Transformation Energies for Nitride and Carbide Phases

1 Metastable -a Stable Structural Transformation Energies for Nitride and Carbide Phases 

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Stolten has developed a semi-empirical estimation method to obtain enthalpies of formation of carbides, nitrides and oxides in metastable crystallographic structures. The calculations involved are based on the classical alloying criteria of atomic size, valence and electronegativity, and incorporate a correction factor obtained 

Fernandez Guillermet and Grimvall have also written a series of papers [11-17] devoted to deriving enthalpies of formation and standard entropies for a range of metastable carbide and nitride phases of the 3d, 4d and 5d transition metals. Thermodynamic values were obtained from an analysis of the cohesive properties and vibmtional entropies of the compounds concerned, whereby a quantity with the dimensions of energy, E, was defined as 

The derived values were found to vary in a regular and related way when studied as a function of the average number of valence electrons per atom in the compound, n.  

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