Corrosion problems in electrolytic processing

Special mention may be made of cases of corrosion damage associated with processes utilizing electrolytic cells or reactors. Possible effects include the following  

Current on dissolution of inert anodes or unwanted attack on electrode feeders due to aggressive species in the electrolyte, a.c. ripple from the power supply, or poor electrode/feeder design. 

Current on cathode dissolution, particularly due to combination of electroreduction of protective surface films and active generation of hydrogen. This may be especially marked in the case of titanium, due to facile hydride formation. The result may be pitting, embrittlement or exfoliation of the electrode surface. Electrode corrosion may significantly alter electrocatalytic properties (resulting in a reduced selectivity) contaminate electrolytes (and, hence, products) block cells, dividers or manifolds cause electrical shorting, or provide parasitic redox couples (e.g. Fe /Fe ) which decrease current efficiency or promote deposit or bimetallic corrosion efficiency elsewhere. 

A number of the above comments also apply to, for example, electroplating cells, which may have other specific corrosion problems (Fig. 10.37). 

Oxide film formah on provides high resisfance of fhe busbar-feeder join and may cause overheating or intermittent contact 

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