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Electrochemical corrosion behavior of modified 9Cr-1Mo alloy

Thesis/Dissertation ·
OSTI ID:5215276

The electrochemical corrosion behavior of modified 9Cr-1Mo alloy was studied in aqueous sulfate solution, with emphasis on the active dissolution, active-passive transition and passive film growth as a function of electrode potential, electrolyte pH and temperature. The primary electrochemical techniques employed were potentiodynamic, potentiostatic and galvanostatic polarization measurements supplemented by ESCA measurements of the anodic oxide film formed at various potentials. Passivation potential and critical current density of modified 9Cr-1Mo alloy were found to be significantly lower than those of pure iron, indicating alloying iron with chromium facilitates passivation. The oxidative dissolution of chromium oxide, the secondary passivation, and oxygen evolution were observed at the relatively higher oxidizing potentials. The anodic current under conditions of controlled constant potential decreased with increasing pH. Evidenced by ESCA, the excellent corrosion resistance of the iron-chromium alloy is strongly believed to be due to the enrichment of chromium on the surface which blocks the dissolution of iron.

Research Organization:
Utah Univ., Salt Lake City, UT (USA)
OSTI ID:
5215276
Country of Publication:
United States
Language:
English