Electroless Plating Ni-sn-p Alloy

This paper described a novel method for preparing amorphous Ni-Sn-P alloy coating by electroless plating. The effects of contents of nickel chloride, tin tetrachloride, lactic acid, sodium citrate and reducing agent on the properties of alloy were studied. In addition, the pH value, plating time and temperature which affect the plating rate, surface topography, composition and structure of the coating were also discussed in this paper. The alloy was characterized with SEM, EDS, ASS, XRD and electrochemical analyzer. Based on single-factor research, optimal technology conditions were obtained as following:the pH value is 5.5, the contents of reducing agent, nickel salt, tin salt and complexing agent are 40 g/L,20 g/L,20 g/L and 140 g/L, respectively, and the temperature is 90℃. Using this technology, we had prepared a amorphous Ni-Sn-P alloy coating which consists 28.3% tin. The results indicated that alloy has fast plating rate in the plating solution developed by this experiment and the coating obtained has better corrosion resistant ability, high welding capacity and excellent oxidation resistance, which may effectively prevent the phenomena of "grain boundary attack" and "black pad" under the immersion gold process. It could be applied in PCB industry and decoration coating field.