Potentiostatic Cu-Zn Alloying for Polymer Metallization Using Medium-Low Temperature Ionic Liquid Baths

Abstract

Cu-Zn alloy formation on a non-conductive epoxy substrate was demonstrated through successive electrochemical processes: (i) conventional electroless Cu deposition on the substrate using an aqueous bath, and (ii) electrochemical alloying of the resulting Cu layer with Zn using a reduction-diffusion (RD) method in a Zn2+-containing ionic liquid bath at 150°C. The obtained Cu-Zn alloy layers were adhesive and were uniformly grown with maintaining the surface morphology of the initial electroless Cu. The Cu-Zn phases, i.e. γ-Cu5Zn8, β′-CuZn, and/or α-Cu(Zn), which define the color of the layers were dependent on applied potential during the RD alloying. Thermodynamics of the alloy formation was also discussed. © 2013 The Electrochemical Society. All rights reserved.