CHEMICAL STATE OF THE SURFACE OF MECHANICALLY ACTIVATED MnmOn OXIDES

X-ray photoelectron spectroscopy is used to study Mn3O4, Mn2O3, and MnO2 manganese oxide surfaces subjected to mechanical activation by means of high intensity grinding. It is found that Mn2O3 is the most thermodynamically stable of these oxides; mechanical activation converts the surface layers of Mn3O4 and MnO2 into this intermediate oxide. The chemical stability of activated Mn2O3 with respect to actions of the environment was considerably elevated. This result is explained in terms of features of the structural state of the mechanically activated surface.