Experimental investigation of pitting corrosion at channel electrodes

2 Experimental investigation of pitting corrosion at channel electrodes 

Beck and Chan [112] employed a pulged-flow technique to study the effect of convection on the pitting corrosion of iron, in which the effect of a flow 

The effect of convection on the pitting behaviour of stainless steel 304 is in total contrast to that of pure iron, in that removal of the metal salt film leads to the repassivation of the metal surface. Harb [113] has recently investigated the pitting-convection behaviour of single pits in a pH 3.5 solution of 0.1 M Na2S04 and 0.2 M NaCl. Basing his analysis on the concept of a critical Peclet number [113], he showed that high Peclet numbers (Pe 10) favour removal of the dissolution products from the pit surface and subsequent repassivation, whilst for flow rates and/or pit radii for which 

The same phenomenon was also observed by Beck and Chan [112] in their investigation of the pitting of stainless steel in a chloride aqueous medium. Analysis in terms of the theory outlined in Sect. 6.3.1.(b) predicted that the critical velocity for repassivation varied as r 4/3. 

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