Electrical Properties and Morphology of Electrodeposited Cobalt-Nickel-Iron on Flexible Printed Circuits

Abstract

Electrodeposition is a method to electrochemically deposit alloy on various types of metal. This method has ability to produce protective coating and thin films on the metal. In this research, one of the electrodeposition methods, Cyclic Voltammetry (CV) with 10 and 20 cycles was applied to deposit Cobalt-Nickel-Iron (Co-Ni-Fe) on Electroless Nickel Immersion Gold (ENIG) Flexible Printed Circuits (FPCs). The main purpose of this paper is to investigate the electrical properties, morphology and crystallographic structure of the electrodeposited coating. Curve Trace test was conducted to identify the contact resistance of the coating. In this case, the allowable contact resistance should be less or the same as ENIG FPCs which is 1.6 Ω. Morphology of the coated circuit was observed by using FESEM while crystallographic phase of the coating was identified by XRD. Morphology study on Co-Ni-Fe coated FPCs exhibited Cauliflower like shape with average grain size of 1.49 μm and 1.88 μm for 10 and 20 cycles, respectively. CoFe, FeNi and CoO.NiO phases was noticed in the electrodeposited coating. The obtained result showed that the electrodeposited Co-Ni-Fe produced with 10 cycles has the same contact resistance as ENIG which is 1.6 Ω. 20 cycles of CV produced 1.4 Ω of contact resistance, slightly smaller than the other FPCs. This research revealed that electrodeposited Co-Ni-Fe is suitable to be applied as a protective coating while still maintaining the electrical properties of FPCs.