| 摘要 |
PROBLEM TO BE SOLVED: To enhance the solderability of a lead material and to make it possible to increase the welding strength of the welding part of the lead material with an aluminium wire or the like, by a method wherein the melting temperature of a second plated layer is made lower than that of a first plated layer. SOLUTION: A plated layer of two-layer structure, wherein a first plated layer 2 and a second plated layer 3 are laminated in this order of the layer 2 and the layer 3 on the surface of a conductive substrate 1, is formed. In this lead material A, the melting temperature of the layer 3, which is the uppermost layer, is set lower than that of the layer 2, which is positioned under the layer 3. Therefore, even if the layer 3, which is the uppermost layer, is molten when soldering to the uppermost layer is performed, melting of the layer 2, which is positioned under the layer 3, is not caused. As a result, this layer 2 results in functioning as a barrier to Cu or the like diffusing thermally from the conductive base body 1 by heat at the time when the layer 2 is soldered. Accordingly, the deterioration of the solderability of the material A is inhibited and a good bonding strength between a solder on the layer 2 and a solder on the layer 3 is obtained. |
