Volatile anodizing electrolytes for tantalum

摘要

A dielectric film is formed on tantalum pellets by anodization up to 350 V in an electrolyte of an aqueous solution of an organic carboxylic acid with an ionization constant between 10-2 and 10-5. The tantalum pellets are suspended from aluminum-magnesium alloy bars into the electrolytic solution with the bar itself being suspended in the electrolyte. The organic carboxylic acid solute residue from anodization is readily volatile at 200 DEG C. The acid is sometimes combined in the electrolyte with ammonia or an amine having a boiling point less than 200 DEG C.; the electrolyte residues from anodization in these systems are also volatile at 200 DEG C. After anodization, tantalum pellet and aluminum-magnesium bar cleanup is thus accomplished by a brief heat treatment at 200 DEG C., eliminating the need for an extended rinse procedure.