engleski

Electrochemical study of AISI 316L steel after welding

The subject of investigation was the corrosion behavior of the base and weld metals as dependent on a protective passive film formed on the steel surface following exposure to 3.5 % NaCl (pH=5.0). Cyclic polarization was performed in the potential range from – 1.0 to +2.0 V(Ag/AgCl) at different scan rates (10, 50, and 100 mV/s). Impedance measurements were carried out in the range of potential where hydrogen evolution reaction exists and in the passive region (from – 0.2 to +0.5 V(Ag/AgCl)).The pitting potential (Epit) of the weld metal was more positive (0.586 V) than of the base metal (0.472 V), but repassivation potentials (Erp) were the same. A relatively wide plateau of the potential-independent current indicated that passivity was present over a broad potential region (from – 0.2 to +0.5 V(Ag/AgCl)). The Nyquist plots showed a higher charge transfer resistance for the weld metal than for the base metal suggesting an enhanced thickness of the passive film on the weld metal surface.

stainless steel ; welding ; cyclic polarization ; electrochemical impedance spectroscopy

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