Development of a two-dimensional bipolar electrochemistry technique for high throughput corrosion screening

Bipolar electrochemistry allows testing and analysing the crevice corrosion, pitting corrosion, passivation, general corrosion, and cathodic deposition reactions on one sample after a single experiment. A novel two-dimensional bipolar electrochemistry setup is designed by using two orthogonal feeder electrode arrangements, allowing corrosion screening tests across a far wider potential range with a smooth potential gradient to be assessed. The application of this two-dimensional bipolar electrochemistry set-up was applied here for the simultaneous measurement of the nucleation and propagation of pitting and crevice corrosion under a broad range of applied potentials on type 420 stainless steel, which has a very short localised corrosion induction time, reducing the error from corrosion induction to corrosion competition, and all pits and crevice corrosion has no lacy cover on it. Results show that crevice corrosion can grain current density easier to support its nucleation and propagation at different potential regions than pitting corrosion.