engleski

Investigation of stainless steel crevice corrosion by a new test method in natural and biosynthetic seawaters, and in chloride solutions

Austenitic and duplex steels have been investigated on the crevice corrosion in natural, synthetic biochemical seawaters, and in 3.5% sodium chloride solution using a new test method developed by the Group Crevcorr of the Marine Corrosion Working Party of the European Federation of Corrosion. Crevice corrosion of passive alloys is one of the main risk of corrosion attack in the seawater. The other generally used tests have been shown to be valuable for ranking different alloys related to the environmental parameters.New test takes into account the geometry of the formed crevice, gasket materials, applied torque, finishing surface and the composition of synthetic electrolyte or natural water, potential increase rate and temperature.In this work the natural seawater from the Adriatic Sea in Dubrovnik, Croatia, was used to be compared with biochemical synthetic water, and the chloride solution, with the sodium chloride concentration adequate to the chloride content at the location in Dubrovnik. In the synthetic seawater organic component was replced by glucose and glucose oxidase. To assess the influence of natural bio film, glucose oxidase, and chloride content, on the crevice corrosion initiation, the monitoring of the free corrosion potential and the redox potential was performed at 20, 30, and 40 centigrades respectively, during five days with steel specimens in all three solutions.

revice corrosion; stainless steel; seawater; chloride solutions

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