| 摘要 |
PURPOSE:To prevent the deterioration of the corrosion resistance of the Ni layer of an Ni plated high-carbon steel wire due to pinholes when the surface of a steel wire is plated with Ni to produce the Ni plates steel wire as stock for a precise spring, by plating the surface of the steel wire with Cu to form an underlayer before the Ni plating. CONSTITUTION:A Cu underlayer 5 of 1-5mum thickness is formed by plating on the surface of a high-carbon steel wire 1 as stock for producing a precise spring, an Ni layer 2 of 1-5mum thickness is formed thereon by plating on the underlayer 5 and the steel wire 1 is cold drawn to a prescribed diameter. Even when pinholes 3 are present in the Ni layer 2, Ni positioned above Cu in a aglvanic series acts as the anode, electric current flows from Ni to Cu at the parts of local cells 4 and a significant anticorrosive effect is electrochemically produced to prevent the corrosion of the Ni layer 2 due to the pinholes 3.
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