Process for converting lead and lead oxides to barium metaplumbate

Abstract

The present invention provides improved processes for forming anti-corrosion layers, particularly barium metaplumbate, on lead, lead alloy-, and lead oxide-containing substrates. The processes of the invention are used to form corrosion-resistant current collectors which are assembled into lead-acid batteries. The inventive methods used to form barium metaplumbate employ a salt solution which includes a barium compound and a solvent salt. In a first embodiment, a substrate material having at least a surface comprising elemental lead reacts with a salt solution to form barium metaplumbate. The salt solution includes a barium compound and an oxidizing agent. The solvent salt or barium compound may themselves be oxidizing agents, or an additional oxidant may be added to the solution. The molten salt solution is applied to the substrate in any known manner such as dipping, spraying, and brushing. Advantageously, a lead or lead alloy-containing substrate is dipped into a molten salt solution heated to a temperature at which a portion of the lead-containing substrate is directly converted to barium metaplumbate. In a further embodiment of the invention, barium metaplumbate is formed on a lead oxide-containing substrate. This process employs a salt solution comprising a barium compound and a solvent salt to convert lead oxide to barium metaplumbate.