Electroless deposition of Ni-Sn-P coatings and study of their corrosion behavior

The aims of this study are to develop electroless Ni-Sn-P coatings and study their properties such as surface morphology, composition of the coatings and,corrosion behavior in sulfuric medium. The main mechanism of electroless alloy deposition in this work is based on the hypophosphite oxidation as a source of electrons for metals and phosphorous reduction. The surface morphology of the coatings were studied by Scanning electron microscopy, The effect of different percentages of P and Sn on the surface morphology of the coatings were investigated. Elemental analysis with energy dispersive X-ray Spectroscopy technique demonstrated that composition of the coatings are uniform and Varying the sodium hypophosphite concentration in the plating bath varies the percentages of P and Sn in the coatings. Electrochemical analysis in the 10%wt H2SO4 proved that Ni-Sn-P coating with 86.32 %wt Ni- 5.54%wt Sn-8.14%wt P in comparison with other coatings in our study has the best corrosion resistance.