Enhancement of electrical conductivity and corrosion resistance by silver shell‑copper core coating of additively manufactured AlSi10Mg alloy

Abstract

A silver shell‑copper core coating was applied on additively manufactured (AM) AlSi10Mg alloy to improve the electrical conductivity, corrosion resistance, surface roughness and indentation hardness. Surface microstructure evolution and roughness of the AM alloy, i.e. as-built, during the subsequent processes, such as heat treatment, shot peening and AgCu coating, were comprehensively characterized using secondary electron imaging in a scanning electron microscope and a scanning laser microscope, respectively. Also, the surface indentation hardness of the coated alloy was evaluated to study the mechanical response. The corrosion behavior and electrical conductivity of the AgCu coated AM alloy were evaluated and compared with the as-built and shot peened AM alloy using the electrochemical and the electrical resistivity measurements, respectively. The results showed that the AgCu coating could significantly increase the surface hardness of the AM AlSi10Mg four times along with an average of 60% improvement in roughness. The electrochemical characterization shows a significant increase in the corrosion resistance for the AgCu coated AM AlSi10Mg with a low corrosion current density of 4 μmA/cm2 in a chloride solution compared to the uncoated alloy. Finally, it was observed that the AgCu coating leads to reduction of the electrical resistance of the studied AM alloy by 40%. Consequently, the electrical conductivity property of the coated AM AlSi10Mg increases.