Title of Paper:Electrochemical behavior of passive film on 304 stainless steel and chromaticity inspection method of film quality

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Date of Publication:2012-01-01

Included Journals:CPCI-S

Page Number:161-167

Key Words:Stainless steel; Chromaticity; Passive film

Abstract:The passive film formed on 304 stainless steel during self-passive in air was characterized by a chromaticity inspection technique, and the stainless steel after chemical passive in HNO3 solution was examined for comparison. The a* value measured by the inspection nonlinearly decreases with prolonging self-passive time, while it is close to zero for the chemical passive sample. Electrochemical behavior of passive film in the 3.5 wt. % NaCl solution reveals that the resistance of passive film from EIS examination decreases with increasing a* value, and Mott-Schottky analysis indicated that both donor and acceptor density in passive film is non-linear correspond to a* value. It is considered that the growth of outer Fe-richen oxide and inner Cr-richen oxide in the passive film is responsible for the measured a* value and its relationship with the electrochemical behavior.