Pitting Potential of stainless steels in artificial sweat

Abstract The pitting potentials of 12/12, 316 PX, AISI 303, 304, 316F and 316L austenitic stainless steels were determined in artificial sweat (perspiration) at room temperature. Two compositions of sweat were used: the BAM composition which contains two malodorous organic acids and the composition proposed in an ISO standard which does not contain them. The quasi‐potentiostatic method (10 mV potential steps per min), potentiodynamic technique (1 V/min linear sweep) and scratch test were used on mechanically polished and HNO 3 ‐passivated surfaces. The aggressivity of the two artificial sweats with respect to stainless steels was found to be practically the same. The pitting potentials and the classification of the stainless steels according to their pitting potential values were found to depend on the surface preparation and, to a lesser extent, on the test method. The experimental techniques were often complementary and a combination of two or three methods in conjunction may increase the confidence with which the conclusions can be applied. The lowest pitting corrosion resistance was found for AISI 303 and the highest for AISI 316L. As expected stainless steels with the lowest concentration of nonmetallic inclusions (sulfides and oxides) exhibited the best pitting corrosion resistance.