Energy state of a surface of carbon steels as a characteristic of their corrosion resistance

The state of various areas of the surface of a test melt of carbon steel containing 0,2% of carbon and 0,75% of chrome was analyzed by means of methods of energy-dispersive analysis and scanning tunneling micro- and spectroscopy. Without corrosion-active sulfide inclusions, the local corrosion spots are inert chromium carbides and oxides of aluminum. Spots of localized corrosion occur in places where above mentioned carbides and oxides brake the surface due to accelerated etching of the metal/inclusion boundary, where are seen a rapid increase of the tunneling activity.