Galena oxidation was investigated by AFM in acetate buffer under potentiostatic control and by photoelectron spectroscopy on potentiostatically pretreated specimens. At +236 mV (SHE) formation of sulfur protrusions could be observed with AFM. XPS showed the formation of elemental sulfur to start at potentials more anodic than +161 mV (SHE). Elemental sulfur could only be retained on the galena surface if sample cooling was started before the beginning of the evacuation in the spectrometer entry chamber. Sulfur−oxygen species could not be detected on galena samples oxidized in acetate buffer even when investigated with synchrotron-excited X-ray photoelectron spectroscopy. AFM images showed two important features: Oxidation starts with a roughening of the sample surface. At slightly more anodic potentials oxidation products are present on the samples as protrusions of 10−200 nm in height and with mutual distances of several hundred nanometers. Two types of sulfur deposits are formed differing in the emerge...