Abstract
The anodic behaviour of the lead amalgam electrode has been investigated in aqueous hydrochloric acid solutions. Both voltammetric and potential pulse results are described. The mechanism of passivation is shown to be the nucleation and growth of three-dimensional nuclei of PbCl 2 which progressively block the electrode. The nuclei are considered to be right circular cones, distributed at random on the electrode surface. As in the case of solid lead electrodes, a simultaneous dissolution of PbCl n 2− n complexes is observed, which diffuse away from the electrode under mass transport control. Evidence is also presented that the first stage in the growth of the anodic film is the two-dimensional nucleation and growth of a monolayer of PhCl 2. Unfortunately, this process is partially obscured by the dissolution reaction. A reaction scheme is proposed.
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