A Study On Stability Of Electroless Ni-P Solution

At present, the stability of electroless Nickel plating soln. is not only the focus of the electroless Nickel industry in the world, but also a study problem, because it was relation to the cost of electroless Nickel and environmental protection directly. The present situation and development are reviewed on the base of studying a host of paper and books. As for the problem of soln. stability of electroless Nickel-Phosphorus alloy, all of the factors that influence the stability are studied and the long service life electroless Nickel technology are quested in detail with methods of palladium chloride testing of electroless Nickel soln., stability constant and the Service life. Moreover, the effect measure for improving the stability and the stability mechanism of electroless Nickel soln. are also researched preliminary.The research results show that all of effect composition in the electroless Nickel solution may influence the stability, of which complexing agent and stabilizer are the most important factors. In the process of operation, temperature and pH value are the main factors. In the process of continual operation, the supplement method will decide the service life of soln.The questing for long service electroless Nickel technology leads to the preferable formula and operation conditions as follows:Nickel Sulphate 25g/L, Sodium Hypophosphate 30g/L, Lactic Acid 20~ 25ml/L, Citric Acid 5g/L, Sodium Acetate 15g/L, Thiourea l~3mg/L, Stabilizer E Img/L. pH value 5.0~5.1, Temperature 90+2C, Loading Capacity ldm2/L, Testing the consumed effect ingredients of solution and supplement inspissation's solution every 60min.With this technology, the solution service life will be up to 15MTO or more on the condition of small experiment which the solution volume is 500ml, if enlarge the solution volume to 40L or more for the industry application, the service life will be up to 10MTO around, the coating's appearance is brightness and smooth, surface structure is compact and even, has low porosity, a good hardness (HVioo 420~520, the coating's deepness is 50~78 u m), excellent wearability and corrosion resistance. All the properties meet the requirements of industry application...