High plasticity and anodic behavior of electroformed nickel without chloride ion

• The elongation of the electroformed nickel prepared without chloride ion can be as high as 20%.
• In order to choose the suitable anode, the anodic passivation curves were measured for researching the anodic behavior.
• The concentration of nickel sulfamate, boric acid and pH value in the solution keep stable during the experiment.

A new process to prepare the electroformed nickel without chloride ion activating the anode in the solution is employed in this study, where the sulfur nickel is used as anode. The concentration of nickel sulfamate and boric acid and the pH value were measured during the electroforming process, as well as the anodic passivation curve. The microstructure was observed by means of optical microscope (OM), transmission electron microscope (TEM), and the mechanical property was investigated by tensile experiment. The results show that the concentration of nickel sulfamate and boric acid remains stable with the values of 425 g/L and 35 g/L respectively during the process of electroforming while the pH value keeps stable. The electroforming process could continue without chloride ion as the activator of the anode. The grains of electroformed nickel are very fine and their average size is 5 μm. The elongation of electroformed nickel without annealing treatment reached up to 20%, and the tensile strength was 460 MPa. In this case, electroforming without chloride ion as the activator of the anode is an outstanding method for the electroformed nickel with the excellent mechanical property.

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