THE USE OF SYNTHETIC HYDROTALCITE AS A CHLORIDE-ION GETTER FOR A BARRIER ALUMINUM ANODIZATION PROCESS

Chloride ion contamination at parts per billion concentrations slows b arrier anodic aluminum oxide film growth rate and detracts from film q uality. It has been determined that synthetic hydrotalcite can be used to substantially reduce the detrimental effects of chloride ion conta mination in an aqueous-based electrolyte used to grow barrier anodic a luminum oxide. Precautions must be taken so that this material does no t come into contact with the aluminum substrate during anodization.