SEMICONDUCTIVE PROPERTIES OF PASSIVE FILM FORMED ON 304L STAINLESS STEEL
304L不锈钢钝化膜半导体性能研究

The semiconductive properties of passive film formed on 304L stainless steel in 0.5 mol/L NaHCO_3 solution were detected using polarization curve,capacitance measurement and X-ray photoelectron spectroscopy(XPS) measurements.In addition,the factors which affect the semi-conductive characteristic of the passive film was also discussed.The results show that the passive film exhibits p-type semiconductive characters in the potential region lower than -0.4 V,and n-type semiconductive chracters in the potential region of-0.4V to 0.26 V.With the measured frequency decreasing and film formation potential moving to much negative,the slopes of M-S plots decreases,this indicates that the impurity density in the film increases.The addition of chlorine ion in the solution can decrease the slopes of the M-S plots,and enhance the occurrence of pitting corrosion on the 304L SS.The XPS result ravels an inner layer of Cr oxide and an outer layer of Fe oxide,which is in agreement with the previous works.