Electrochemical and Physical Properties of Nanocrystalline Copper Deposits Produced by Pulse Electrodeposition

Abstract

This paper reports our recent studies on nanocrystalline layer of copper produced using pulse plating method. The grain size of the copper layer was about 60 nm. Electrochemical and physical Properties of the nanocrystalline surface were investigated using Potentiostatic scanning and Impedance measurements. Microcrystalline copper deposits were also produced by direct current electrodeposition processes and compared with pulse plated ones. Effects of deposition parameters, such as the peak Density, frequency, current-on time and current-off time of the pulse current (PC), on the grain size were investigated for the purpose of process optimization. It was demonstrated that the nanocrystalline film was markedly superior to regularly grained film made by direct current (DC) plating; the nanocrystalline deposit shows higher electrochemical stability and lower electrical resistance.

Oxidation and Corrosion Resistance of Nanocrystalline Copper Deposit Produced by Pulse Electrodeposition

“…Since these boundaries have high activity, they react with oxygen rapidly and form a compact oxide layer on their surface. This protective layer acts like a barrier and inhibits easy diffusion of copper atoms to the interface of oxide-oxygen and therefore slows down the oxidation progress [14][15][16][17]. However in copper sheet, because of low grain boundaries density, the adhesion of oxide layers to the sheet was poor.…”

Friction-assisted pulse electrodeposition of high-performance ultrafine-grained Cu deposits

“…To avoid the potential deterioration of deposit quality in the process of grain refinement, pulsing is an effective method, and previous studies [1,14,17] have shown that pulse electrodeposition can be used to obtain a more uniform and dense coating while refining the grain size. Shen et al [18] maximised the control of the concentration polarisation by flushing the cathode surface with a strong electrolyte, leading to a better combination of tensile strength and ductility for NC Cu in an ultra-low sulphate concentration bath.…”

“…An effective method for obtaining strong cathodic polarisation and thus achieving grain refinement is to control the ratio of the working current density to the bulk concentration of the metallic ions ( J / c ) [2]. Many studies [10,13] have shown that the grain size can be reduced using a higher nucleation rate and the grain density can be saturated by increasing the current density, with nanoscale grains possible with a sufficiently high current density [14]. However, at high current densities, constrained mass transfer can result in a powdery surface.…”