Electrolytic Etching and Polishing

There is evidence (8)(21 -24)(71 -75) that during eiectrodissoiution, a passivation fiim is formed on the anode. The film is gradually eliminated by diffusion when the current is switched off. The etching and polishing behavior of an anode are perhaps associated with the chemical stability of this passive film whose composition is usually speculative (21 -23)(72)(74). 

Obviously, in mild etching systems the dissolution kinetics are controlled by surface reactions. 

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