The paper presents the results of theoretical and experimental investigations of phenomena that accompany the formation of nanometer oxide and hydroxide pellicles by applying electrical discharges in impulse (EDI). The chemical content of processed surface analysis (EDX – Energy Dispersive X-ray analysis) attests the presence of oxygen that reaches up to 60% at. for steel surfaces, 30-35% at. for those made of titanium alloys, up to 20% at. for those made of aluminum alloys, and up to 50% at. for those made of copper alloys. The presence of considerable amounts of nitrogen is found only in titanium and iron alloys (and constitutes about 15% at), while in aluminum and copper alloys its presence is not significant. The superficial phase analysis (XPS - X-ray Photoelectron Spectroscopy) of the oxygen allowed us to state that the oxygen in pellicle forms three base structures: -O-2 (oxide), - OH- (hydroxide), and structures of the type О-С and О-С=О. The chemical analysis showed that the concentration of each of the three components is 0.89:1.00:0.50.