How Lead and Lead Alloy Anode is Used in The Electrochemical Process?

How Lead and Lead Alloy Anode is Used in The Electrochemical Process?

Lead has complex electrochemistry when used as an anode material. Pure lead at low current densities dissolves into Pb2+ ions. The measured dissolution rate for pure lead under these conditions is 5 kg / kiloamp-hour. At higher current densities in seawater, lead chloride (PbCl2) forms at the surface. Lead chloride is an insulator that drops power efficiency radically as it thickens due to the IR voltage drop that occurs across the PbCl2 film. Under special conditions however a thin film layer of lead oxide (PbO2) can be formed over the surface of the anode. PbO2 is an electrical conductor that can passivate the surface against both dissolution and lead chloride formation. A lead oxide covered lead anode can have a dissolution rate as low as 0.001 kg / kiloamp-hour.

Lead can be conditioned to form oxide films by alloying and by embedded surface microelectrode arrays. Alloying with silver and antimony produces a surface with localized silver grains that form nucleation sites for PbO2 to form and spread over the entire surface. A similar effect has been observed with lead anodes with platinum microelectrodes (0.5 mm diameter) inserted into the surface. A lower cost method of embedding microelectrodes was accomplished by embedding particles of magnetite in lead.