In order to study the mechanism of the electrochemical polarization and active components reduction influence on the mechanical properties of surfaces, a new method has been developed : microscratching of the sample surface under polarization conditions in an electrochemical cell, with continuous monitoring potential in the area adjacent close to the moving indentor. Essential changes in this potential are observed during indentor movement, corresponding with the high activity of the newly formed surface. The very edge of the surface with a groove, where the hard stressed state is combined with accessibility to the medium state, appears to be the most sensitive to this action. This allows one to observe effects of hydrogen embrittlement and active metal cation reduction in the contact zone.