Abstract
Investigations were made concerning the electroplating of copper on pure (2S) and impure (61S) aluminum anodized in H3PO4 or H2SO4 and the anodic oxide films were studied with respect to the deposition mechanism of metals on anodized aluminum.
(1) When aluminum bases were anodized in H3PO4 baths, smooth copper deposits of 100% coverage were obtained for 61S-Al, but never for 2S-Al.
(2) In H2SO4 anodizing, 100% coverage was achieved for both of 61S-Al and 2S-Al only when the oxide films were relatively thin (<3μ).
(3) The X-ray diffraction and infrared absorption spectrum of the oxide films revealed no differences in crystallographic and mechanical structures between H3PO4 and H2SO4 anodizing for each of 2S and 61S oxide films.
(4) The current-time curves during the potentiostatic cathodic polarization of anodized aluminum specimens suggested that the oxide film formed in H3PO4 was stronger and more adhesive than that formed in H2SO4, and electric conductivity of films was believed to be constant.
(5) It was also suggested that some impurities in aluminum base remained in the oxide film formed in H3PO4 and acted to form nuclei in the subsequent plating process.
