Passive film on 2205 duplex stainless steel studied by photo-electrochemistry and ARXPS methods

摘要

The passive film formed on 2205 duplex stainless steel in pH 8.59 borate buffer solutions was studied by photo-electrochemical techniques and Mott-Schottky analysis. The passive film displays both n-type and p-type semiconductor character in different potential regions of the passive state. The band gap energy of barrier layer of the passive film was 2.4 similar to 2.75 eV. Additionally, the composition of passive film was analyzed by AR-XPS; at -400 similar to 100 mV(SCE) and above 600 mV(SCE) Fe2O3, Fe3O4, FeOOH and CrO3 dominate the passive film, showing n-type semi-conductivity; while at 100 similar to 600 mV(SCE) the passive film comprises FeO, Cr2O3 and Cr(OH)(3), exhibiting p-type semi-conductivity.