Effects Of Pulse And Pulsed Reverse Electroplating Parameters On SN And SN-NI Alloy Coatings Of Steel Sheet Properties

Sn and Sn-Ni coatings with excellent corrosion resistance, weldability and otherapplication performance, are widely used in the packaging and decoration industries.However, with the rising price of Tin and Nickel in the whole world, reducing thethickness of Sn and Ni coatings has become a major research project. Due to the effect oflessening the concentration polarization and increasing the electrochemical polarization,the Sn and Ni coatings can be improved effectively by pulse plating power. Therefore,remaining the better corrosion resistance of coatings, the use of pulse plating power toreduce the coatings thickness will be a new idea.In this paper, the Sn and Sn-Ni coatings with better corrosion resistance were obtainedusing electroplating method by optimizing the plating process and replacing the traditionalDC power with pulse plating power. Single factor test and orthogonal test were applied todetermine the optimum operating parameters of pulse power. The self-corrosion currentdensity of the coatings was used as a reference standard. The compositions andmorphologies of the Sn and Sn-Ni coatings plated at different pulse power parameterswere investigated by X-ray diffraction technique and scanning electronic microscope. Thecorrosion weightlessness test and the electrochemical test were applied to research theanti-corrosion property of Sn and Sn-Ni alloy coatings. Contrast tests were conductedbetween the DC plating coatings, the pulse plating coatings and the pulse reverse platingcoatings. The conclusions are as follows:The deposition rate of pulse plating power is larger than DC power. As additivecontent of tin plating solution in30ml/L, tin coating surface morphology is best. In theSn-Ni plating solution, the best coating surface morphology were obtained with5g/Ladditive content. The mass fraction of tin in the alloy coatings is65%, and nickel is31%.Scanning electron microscopy showed either tin or tin-nickel alloy pulse plating coatingsis more dense and smooth than DC plating, and the pulse reverse plating coatings showeda better surface performance than the pulse plating coatings. The conclusions of corrosionweightlessness test and the electrochemical test showed that the corrosion resistance of thepulse plating coatings of the tin and tin-nickel alloys was better than that of the DC plating coatings, and the pulse reverse plating coatings showed a better performance in theanti-corrosion property than the pulse plating coatings. In the same anti-corrosion property,the thickness of pulse reverse plating tin coatings20%thinner than pulse plating tincoating’s, and35%thinner than DC plating tin coating. And the thickness of pulse reverseplating tin-nickel alloy coating thinner20%than pulse plating coating’s, and40%thinnerthan DC plating coating’s.