Pulse Electrodeposited Nickel Alloy

The principle and advantage of pulse electrodeposition were introduced in this paper. The application status of pulse current electrodeposition in Ni and Ni-P, Ni-Fe, Ni-Zn, Ni-Co, Ni-Cu were summarized in this paper. In addition, the developing trend of pulse electrodeposition was previewed.Nickel-based alloys are used in a wide variety of applications for aerospace, energy generation and corrosion protection, especially in an environment where materials have to withstand high temperature and oxidizating conditions. Among these materials, Ni-Co alloys find applications in a variety of high technology applications because of their unique properties:magnetic, wear resistance, heat conductivity, and electrocatalytic properties. These properties are directly related to alloy composition and structure. Especially Ni-Cu alloys containing approximately 30 wt% copper are highly corrosion-resistant in sea water, acidic and alkaline media and in many oxidizing and reducing gas environments.Pulse electrodeposition is a modern electrochemical method that improves/modifies the quality of the deposits better than that of direct current. In the case of pulse plating, as in any electrodeposition process, the microstructure of the layer is dependent on crystallization and growth. The influence of pulse parameters on electrodeposited layers which were plated on aluminium alloy using pulse current were studied in this paper. The details are as follows:The polarization curves and the effect of every additive in electrolyte were measured by electrochemistry experiments. The results indicated that the deposition of Ni-Co alloys were effected on the reductive deposition of Co. And the Ni-Co is an anomalous type of deposition.The electrodeposition of the Ni-Co alloys were carried out in these baths using analytical reagent grade chemicals as follows:NiSO4·6H2O 240g/L,CoSO4·7H2O 8g/L,H3BO3 45g/L,NaCl 20g/L. The temperature of the bath was kept at 55±2℃. The pH value of the electrolyte systems was kept at 4.3 and the average current density ranged between 2.8 and 3.2A/dm2. The influence of the frequency, pulse duty cycles on inner stress, electrodepositing speed, Co content, surface micro-topography and corrosion resistance were studied.A new process was determined based on the selection of EDTA, pyrophosphate, citrate in sulfate solution with hull cell tests. The appearance and the distribution of electric current density on the Ni-Cu samples were researched. Then, we used C6H5Na3O7·2H2O for pulse electrodeposited.The electrodeposition of the Ni-Cu alloys was carried out in these baths as follows: NiSO4·6H2O 120g/L,CuSO4·5H2O 10g/L,C6H5Na3O7·2H2O 70g/L,H3BO3 20g/L,NaCl 12g/L. The temperature of the bath was kept at 40±2℃, and pH was 5.1. The influence of the frequency, pulse duty cycles on inner stress were studied primarily.