| 摘要 |
Disclosed is a tinned bar with excellent abrasion resistance, insertion properties and heat resistance that is suitable for use as conductive spring material. In an electroplating process, the surface of a copper alloy bar is base-plated and then Sn-plated. This is followed by a reflow process. The height difference between the outermost surface of the Sn plating and the outermost point of the Cu-Sn alloy phase of the copper alloy tinned bar is 0.1-0.5 mm, the maximum height of the roughness curve of the Cu-Sn alloy phase is 0.6-1.2 mm, the average length of the roughness curve of the Cu-Sn alloy phase is 2.0-5.0 mm, and preferably 2.0 = Rsm/(y + Rz) = 4.0. From its surface to the base material, the plating film consists of a Sn layer 0.5-1.5 mm thick, a Cu-Sn alloy layer 0.6-2.0 mm thick, and a Cu layer 0-0.8 mm thick, of a Sn layer 0.5-1.5 mm thick, a Cu-Sn layer 0.4-2.0 mm thick, and a Ni layer 0.1-0.8 mm thick. |
