Electrodeposition of Co-Ni-Fe thin film using hull cell

Abstract

Corrosion of copper occurs when it is exposed to the atmosphere and oxidizes, causing bright copper surfaces to become dull and discolour. After a few years, it slowly changes to dark brown and finally green. In this study, the copper plate was coated with cobalt-nickel-iron (Co-Ni-Fe) alloy using electrodeposition in a hull. The process was done for 15 min using platinized titanium as the anode and the copper plate as cathode. The electrolyte was sulphate solution and the working temperature was 50 °C. This method allows a variation of thickness, microhardness, morphology and composition of the coating which were influenced by different local current density. Multiple tests were conducted to obtain the desired properties of the coating using 3D surface metrology system, Vickers microhardness tester, and scanning electron microscope (SEM). The copper plates had uniform coating of Co-Ni-Fe at the surface under the examination of SEM. In conclusion, the thickness and microhardness of coating increase when the current density increases. Furthermore, this method improved the mechanical properties of the copper plate because the microhardness of the coating was 285.3 HV compared to 126.4 HV of the copper plate. Some voids and agglomerates were found on the surface of the coating when deposited at low and high current density. The desirable surface morphology was obtained at 32.29 mA/cm2 but with a trade-off having moderate microhardness.