Electrochemical determination of corrosion protection and phase composition of nitride layers on steels

Abstract

Electrochemical method providing the possibility to check the penetrating porosity, corrosion resistance and phase composition of nitrided surface has been developed and applied for high-speed SW18 steel nitrided from plasma excited H2 +N2 gas mixture and for structural 10A and 45A steels nitrided from NH3 gas dissociated at different parameters. By selection the appropriate electrolytes, the phase composition of nitrided layer in SW18 steel, and the corrosion resistance of e or γ' compact nitride layer on 10A and 45A steels have been evaluated and confirmed by material science and corrosion tests. Electrochemical methods may be applied to control the quality of obtained nitrided layer, and to correct or modify the
program of technological process. Electrochemical method provided the possibility to check the penetrating porosity, corrosion resistance and phase composition of nitrided surface By selection the appropriate electrolytes, the phase composition and the corrosion resistance of nitride layers formed on SW18, 10A and 45A steels were established in accordance with the material investigation and corrosion tests data.