ABSTRACT
The corrosion behaviour of passive materials and particularly stainless steels is strongly dependent on the passive layer properties. When immersed in sea water, these passive layers may alter with the duration of immersion and are a function of several parameters such as temperature, oxygen content, biofilm formation, etc.
This means that the corrosion behaviour of stainless steels may depend on the immersion time. Experimental tests have been performed to investigate this influence of the ageing of stainless steels when they are exposed to sea water. AISI 316 L stainless steel with different surface treatments was tested. Experiments were conducted with synthetic sea water and the biofilm effect was simulated by hydrogen peroxide and acid additions in order to obtain a free corrosion potential of about +300 mV (SCE). Electrochemical and crevice corrosion tests show clearly a better corrosion behaviour of the 316 L specimens which have been previously immersed at least 15 days in synthetic sea water.
