Surface physics and chemistry of carbon fibers enhance dissimilar sheet joining of carbon fiber-reinforced plastic by copper electrodeposition

Abstract

Carbon fiber-reinforced plastic (CFRP) sheets were dissimilarly edge-joined with anodized A6061 Al alloy sheets by copper electrodeposition. A high bonding strength of 137 MPa was attained following a series of pretreatments including etching in KMnO₄ + NaOH hot aqueous solution, anodization at 2 V vs. SUS316 cathode in 1 mol L^˗1 H₂SO₄, and sulfonation in hot concentrated H₂SO₄. The anodization physically cleaned the carbon fiber (CF) surface in CFRP. The chemical surface properties of the CFs were modified by the anodization, introducing crystallographic defects and CO groups. This physical and chemical modification of CFs in CFRP resulted in good adhesion of the electrodeposited copper.