| 摘要 |
PURPOSE:To prevent the diffusion of the copper component of the core to the surface and to obviate the surface discoloration and deterioration of corrosion resistance by increasing the diameter of the copper crystal grain in the core and coarsening the diameter of the crystal grain in the nickel plating layer. CONSTITUTION:The Ni-plated copper wire consists of copper or a copper alloy, and an Ni plating layer having 0.1 - 5.0mu thickness is formed by electroplating on the surface of the core with the copper crystal grain diameter controlled to >=5.0mu. The core obtained by wire-drawing copper or a copper alloy is annealed to adjust the copper crystal grain diameter to >=5.0mu, and the Ni electroplating layer having 0.1-5.0mu thickness is formed on the core surface to produce the Ni-plated copper wire. In this case, the magnitude of the Ni crystal grain diameter is specified by that of the core copper crystal grain diameter, and an Ni plating layer with less pinholes ad grain boundaries and having a large crystal grain diameter is obtained. Even if the wire is exposed to a high-temp. environment in soldering, etc., ad the copper component in the core tends to diffuse to the surface, the diffusion is suppressed by the Ni plating layer. |
