Solid-State displacement reactions between selected metals and sulfides

Displacement reactions between sulfides and metals in the solid state are studied and compared with the resultant morphologies previously observed in oxide-metal displacement reactions. Sufficient thermodynamic and diffusion data were available only for the theoretical prediction of product morphology for the Fe-Ni₃S₂ reaction couple. Experiments substantiated the theoretical prediction of an aggregate morphology for this couple at 600°C. The growth of the product zone for the Fe-Ni₃S₂ reaction couple obeyed parabolic kinetics. The experimentally observed morphologies for Co-Ni₃S₂, Fe-Co₄S₃, Mn-Crs, Nb-Cu.₂S, Cr-Cu₂S, Cr-Ni₃S₂, and Mn-Cu₂S reaction couples are also reported and rationalized.