Effect of the Pulse Duty Cycle on the Microstructure and Properties of a Jet Electrodeposited Nanocrystalline Copper Coating

Abstract

Nanocrystalline copper coatings were jet electrodeposited using a square-wave pulse current with three duty cycles (30%, 50% and 70%) and a direct current condition. The effect of the duty cycle on the surface morphology, microstructure, grain growth and mechanical performance of the copper coatings was examined. The experimental results revealed that a decrease in the duty cycle significantly improved the coating surface morphology and microstructure. It was shown that a pulse current at a low duty cycle during jet electrodeposition effectively generated a nanocrystalline structure in the coating and improved the mechanical properties. At a low (30%) duty cycle during pulse current electrodeposition, coatings with a fine and smooth surface and dense microstructure were produced with a minimum grain size of 25 nm, microhardness of 2.37 GPa and tensile strength of 712 MPa.