The role of Si addition on the interfacial interaction in FeAl diffusion layer

Abstract

The formation and growth characteristics of the diffusion layers formed at the aluminum-steel interface depend on several factors, such as the crystal structure, the range of solid solubility, the magnitude and sign of interatomic interaction potentials between the atoms of substrate and coating elements, and also their interdiffusion coefficient. The interfacial interactions either increase or decrease depending on the nature of the matrix (substrate), coat and impurity elements. Therefore, control of the interatomic interaction potentials and the diffusion rates of matrix and coat atoms are of particular research interest, since it would be possible to govern the solubility rate of coating elements in the matrix, and consequently the formation of new phases and their thicknesses at the base metal-coat interface by using right impurities and alloying additions. However, in order to determine interatomic interaction parameters it is necessary to calculate the partial ordering energies, W[sub [alpha][beta]](R[sub i]), and pairwise interatomic interaction potentials in the ternary alloys. The procedure for such calculations based on the electronic theory of alloys in the pseudopotential approximation, was given by Mekhrabov et al. In this present work the role of Si on the interfacial interactions in the Fe-Al system and the formation of an aluminizedmore » diffusion layer are discussed in terms of interfacial interaction potentials.« less