| 摘要 |
PROBLEM TO BE SOLVED: To provide a copper alloy capable of stably obtaining good solder weldability. SOLUTION: This copper alloy has a composition containing, by weight, 3.0 to 9.0% Sn and Fe, Ni and P by 0.05 to 1.0% in total, in which the atomic weight ratio of Fe, Ni and P shown by the formula of [(Fe+Ni)/P] is 0.2 to 3.0, and the balance Cu with inevitable impurities, and the number of P compounds with a diameter of 0.001 to 1μm is >=100 pieces/mm. Since Sn, Fe, Ni and P are contained by suitable amounts, mechanism properties required for the material for electronic parts are satisfied, since the atomic weight ratio of Fe, Ni and P shown by the formula of [(Fe+Ni)/P] is prescribed to 0.2 to 3.0, and further, the number of P compounds with a diameter of 0.001 to 1μm is prescribed to >=100 pieces/mm, most P is present as compounds and does not diffuse into the boundary of the solder joint, so that secular deterioration in the solder joinability can be suppressed.
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