Disordered surface layers of metal sulfides and their reactivity
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The surface of metal sulfides during reactions of oxidation and corrosion in aqueous solutions is investigated using X-ray photoelectron spectroscopy, X-ray spectroscopy, Mössbauer spectroscopy, scanning electron microscopy, and scanning probe microscopy. Primary attention is focused on the state of the surface layer of the sulfide phase. It is demonstrated that the composition of this layer is changed in such a way that there arises a metal deficiency (as a rule, rather substantial) and the structure becomes disordered. Experimental evidence that the surface layer can be considered a chalcogenide glassy semiconductors is discussed. The role of the localization of electronic states and specific defects in the reactivity of sulfides, particularly in oxidation and acid dissolution, is analyzed.
KeywordsChalcopyrite Galena Arsenopyrite Glass Physic Bornite
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