Nano-anchor effect by anodic oxidation of aluminum sheets in joining by electrodeposition

Abstract

Two anodized and stacked aluminum sheets were adhered by electrodeposition of copper. The anodizing conditions were varied and the adhesion strength (interface shear strength) was investigated by lap shear tests. The interfacial shear strength depended on the conditions of the anodic oxidation and reached >60 MPa when the aluminum sheets was anodized in H₃PO₄ before electrodeposition of copper. An anodic aluminum oxide film was formed by anodic oxidation (anodization) of the aluminum sheets and had porous structure with straight nanopores perpendicular to the surface. Hence, anodized Al sheets were strongly adhered by Cu electrodeposition because of nano-anchor or interlocking effect between the porous structure and electrodeposited copper. The proposed joining technique through electrodeposition may be useful because it can provide electrically conductive joints at room temperature and ambient pressure.