A PHOTOELECTROCHEMICAL STUDY OF PASSIVE FILMS ONSTAINLESS STEEL IN SIMULATED COOLING WATER WITHSULFIDE

摘要

The photoelectrochemical measurement of stainless steel in simulated cooling water shows that,the passive film on the stainless steel exhibits n-type photoresponse, and the peak of absorption happensat 310nm. The passive film on stainless steel starts to generate photocurrent at potential about -0.35V. Asthe potential rises, the photocurrent increases, and the bandgap energy Eg of the passive film fall. Theaddition of sulfide in the simulated cooling water can increase the photocurrent, and reduce the Eg valuesof the passive film on stainless steel. The greater the concentration of the sulfide is, the larger will be themeasured photocurrent and the lower will be the Eg. That is attributable to the fall of the film resistance ofthe passive film and the decrease of content of chromium oxides in the passive film.