Studies on nickel electrodeposits on dc magnetron sputtered copper substrates

Abstract

Investigations into nickel electrodeposits on dc magnetron sputtered copper substrates are reported. Thin layers of copper were deposited by dc magnetron sputtering on mild steel substrates. Onto these sputtered copper surface, layers of nickel were electrodeposited using a Watt's bath. The coatings were vacuum annealed at 200°C for 120 min. The growth of the deposit is discussed in terms of structural and microstructural analysis by X-ray diffraction (XRD), SEM and atomic force microscopy (AFM). The orientation along (111), (200) and (220) was observed for the vacuum annealed Cu_3·8Ni alloy deposits. Uniform and pinhole free morphology was observed from SEM. AFM images reveal that these coatings have a granular morphology. The corrosion behaviour of these samples in a 3·5 wt-%NaCl solution was examined. A decrease in I_corr and high charge transfer resistance indicated the improved corrosion resistant behaviour of the nickel sample plated over a sputtered copper base.