Selective area deposition of Tin-Nickel alloy coating - an alternative for decorative chromium plating

Sn-Ni alloy coatings on mild steel substrates produced by selective area deposition process with layer thickness of about 14 mu m were investigated with regard to the structural and corrosion properties. X-ray diffraction analysis revealed that the selective area plated Sn-Ni alloy was heterogeneous and composed of NiSn, Ni3Sn2 and Ni3Sn4 phases. Uniform surface coverage of the substrate by granular morphology was observed from SEM and AFM. The alloy composition was determined by X-ray fluorescence (XRF). The corrosion protection performance of Sn-Ni alloy on mild steel was assessed using salt-water immersion and electrochemical corrosion tests. A sharp decrease in I-corr and high charge transfer resistance indicated improved corrosion resistant behavior of the selective area deposited Sn-Ni alloy.