Temperature Acidic Electroless Nickel Plating - P Alloy

The present situation and development of the technology for electroless Nickel are reviewed on the base of studying a host of paper and books, then the advantage and disadvantage of middle-temperature and high- temperature electroless Nickel plating are analyzed and compared, thus the great significance of theory and practice are realize.All of the factors, such as the primary composition of electroless Nickel soln.,the condition of operation and the supplement method, that influence the technology of acidic middle-temperature electroless Nickel-Phosphorus alloy are systemically studied with methods of conditional experiment and the continual experiment in this article. Moreover, from the point of view of kinetics, this article preliminarily researches the mechanism of acidic middle-temperature electroless Nickel plating.The research results show that all of primary composition in the electroless Nickel solution may influence the technology, of which complexing agent and accelerator are the most important factors. In the process of operation, temperature and pH value may influence the technology greatly. In the process of continual operation, the supplement methods will largely affect the service life, the stability and plating rate of soln, and the performances of Nickel-Phosphorus alloy.The questing for acidic middle-temperature electroless Nickel technology leads to the preferable prescription as follows:Proportion of Nickel Sulphate and Sodium Hypophosphate 0.36; Sodium Acetate 15g/L; Stabilizer A lmg/L(Stabilizer B Img/L for continual experiment); Composite complexing agent Lactic Acid 10ml/L and acetic acid 10 ml/L; Accelerator organic acid G 6g/L; pH value 5.0; Loading Capacity ldm2/L; Temperature 70C (Temperature 75C for continual experiment); Proportion of supplement for Nickel Sulphate and Sodium Hypophosphate 1:1.2; Testing the consumed ion of Nickel solution and supplement inspissation's solution every 60min by the proportion of 15% fresh solution.Using the preferable prescription of acidic middle-temperature electrolessNickel technology, acidic electroless Ni soln., of which the service life is more than 10 MTO, with deposition rate 20.40um/h and 12.10um/h at the first MTO and the last MTO, respectively, is developed, and excellent electroless Nickel alloy with a good hardness of 480HV and good corrosion resistance of more than 70s, the highest time 221s is obtained. Moreover, the adhesive strength of electroless Nickel alloy is very favorable and phosphorus content of EN alloy is very steady(continually keep 11-12%). In sum, the integrate properties of coating is very excellent and all the properties meet the requirements of industry application.