The Optimization Of The Process Of Electroplating Amorphous Ni-W-P Alloy

An interest has been taken in developing electroplating ternary Ni-W-P alloy for itsexcellent properties in the scientific community, such as high hardness, wear andcorrosion resistance and thermal stability, good pHysical and chemical properties andsome special functions, such as magnetism, catalysis, etc.. But there are some problemsand deficiencies, for example, the high cost and the poor stability of plating solution, andthe poor quality of the deposit, etc. In view of these weaknesses, the paper aims tooptimize the process of electroplating Ni-W-P alloy on the basis of predecessors. Finally,the coating with superior quality and performance is prepared successfully, and at thesame time the solution has longer service cycle and higher stability.In this paper, nickel sulfate, sodium tungstate and sodium hypophosphite are mainsalt of the solution; boric acid is buffer agent and sodium citrate is complexing agent ofthe solution. Moreover, in order to acpuire superior quality, it is necessary to add somesaccharin and lauryl sodium sulfate to wipe off the stress and make the surface active. Theoptimum formula determined through the orthogonal experiment is NiSO4·6H2O16g/L,Na2WO4·2H2O60g/L, NaH2PO2·H2O4g/L, C6H5Na3O7·2H2O90g/L, H3BO318g/L andmoderate saccharin and lauryl sodium sulfate. And then test the performance of thesolution: the cathode efficiency is32.52%; the deep plating ability is100%and thehomogeneous plating ability is47.68%, which shows the excellent property of thesolution.On this basis, the optimum technology parameter determined through single factorexperiment is that the pH value is6±0.3, the temperature is50±5℃and the currentdensity is4±0.2A/dm2.Then observe the appearance of the coating which is smooth andbright and where there are no obvious defects; and the substrate and the coating have goodadhesion. The paper presents a study of consumption of the main salts ions by inductivelycoupled plasma (ICP) then determine the scheme of adding ions and adjust the pH valueon time by the calculationshou, which lengthen the service cycle of the solution. The effect of the introduction of tungsten in the coating was analyzed by comparingNi-P plating and Ni-W-P plating. The introduction of tungsten changes the coatingcomposition and gets the grains refined and more uniform. At the same time, the coatingbecomes more bright and smooth. Which is more important is that the rate ofelectrodeposition is significantly accelerated and the thermal stability、the corrosionresistance and the hardness of the coating have been increased dramatically.