Experimental Study of Localized Electrochemical Deposition of Ni-Cu Alloy Using a Moving Anode

Nickel-Copper alloys have desirable properties such as resistance to corrosion, resistance to biofouling, and high thermal and electrical conductivity. Due to these properties, these alloys are widely used in offshore applications, oil and gas industry, HVAC systems, as catalysts, and as heat sinks in microelectronics applications. Localized electrochemical deposition of the Ni-Cu alloy would make way for direct 3D microfabrication of parts with this alloy. In this study, Ni-Cu alloy was deposited under different process conditions to establish the feasibility of alloy deposition in the electrochemical additive manufacturing process. Designed 2-factor experiments were performed to study the effects of electrolyte additives, voltage, and pulse frequency on the rate of deposition, and alloy composition. High current density deposition with diffusion limited copper deposition was used to achieve alloy deposition.100 nano second rectangular pulse voltage (10 MHz frequency) conditions resulted in better localization of the deposit when compared to millisecond range pulses. Scanning electron microscope (SEM) with Energy-dispersive X-ray spectroscopy (EDS) quantified the percentage composition of the alloy. The rate of deposition varied from 0.5 μm/s to 3 μm/s. The pillars were thicker under 5 V and millisecond pulse conditions. The nano second pulses localized the deposition to even smaller than the thickness of the micro tool electrode. The ratio of Ni:Cu in the alloy varied between 2 and 14. Citrate electrolyte caused higher deposition of nickel. Higher current density also resulted in more percentage of nickel deposition. Higher frequency of deposition resulted in a reduction of nickel percentage in the deposit.