Study On Obtaining Amorphous Ni-P Alloy Coatings By Pulse Reverse Plating And Factors Influencing Electroplating

Along with the development of scientific and advancing of technology, the capabilities of materials such as corrosion resistance or abrasion resistance are required more higher. At the present, it is the most prevalent that utilizing electroless plating and electroplating amorphous Ni-P alloy coatings, and it has not been reported that utilizing pulse reverse plating amorphous Ni-P alloy coatings. As a new technology, pulse reverse plating are mainly applied to plating noble metal and scarce metal, as it can not only enhance the fine and high temperature resistance, but also improve the coatings quality of complex hardwares. As the model of amorphous alloys, amorphous Ni-P alloy coatings are applied extensively. In order to enhance the capability of amorphous Ni-P alloy coatings and try to find out stable technics of plating amorphous Ni-P alloy coatings, our experiment is unfolded.The experiment regards phosphorous acid-nickel salts bath as basic bath of plating amorphous Ni-P alloy coatings, pulse reverse plating as technique support, and adopt orthogonal experiment and single factor experiment combined as the way and mean of the whole experiment, and manage mature technique to test and figure amorphous Ni-P alloy coatings, accordingly, a series of productions and techniques are educed.For one thing, by way of analyzing a great lot literature and primary trials, twelve fixed technics parameters and six variational parameters are confirmed. The six variational parameters are seen as the investigated parameters of the orthogonal experiment, and being H3PO3, 20~40g/L; the duty cycle R, 30%~70%; average current density Dk, 2~8A/dm2; the reverse duty cycle R,10%~30%; temperature T, 50℃~70℃; pH, 1.0~2.0.Viewing the structure, corrosion potential and depositing rate as the targets of the orthogonal experiment, the result shows that the diffraction apex shape of 24# trial coating is the most smoothest and broadest , and its amorphous characters are the most outstanding. Its experiment conditions are average current density 8A/dm2, the duty cycle 50%, the reverse duty cycle 30%, H3PO330g/L, temperature 50℃, pH 1.0. when the average current density is 8A/dm2, the probability of appearing amorphous Ni-P alloy is the highest. It is attested that utilizing pulse reverse plating to plate amorphous Ni-P alloy coatings can allow to use bigger current than that of direct current plating. By way of analyzing the orthogonal experiment results of corrosion potential and depositing rate, various factors are ranked according to the effect sequence. And the coatings'qualities of pulse reverse plating, pulse plating and direct current plating are compared.In single factor experiment, it is studied that average current density, duty cycle, H3PO3, temperature and C6H5Na3O7·2H2O impact on coatings'qualities, and a series of productions are educed. At the same time, it is studied that the additives impact on surface appearance. the experiment shows that the coating can achieve to optimal effect, smooth, fine and bright when 0.05 g?L-1 sodium dodecyl sulphonate and 0.125 g?L-1 saccharin and 0.1 g?L-1 coumarin are added in the basic bath.