Cu-Ni-Si ALLOY HAVING EXCELLENT FATIGUE CHARACTERISTICS SUITABLY USED AS COPPER ALLOY FOR ELECTRONIC MATERIALS SUCH AS TERMINALS AND CONNECTORS

摘要

PURPOSE: To improve fatigue characteristics of a Cu-Ni-Si alloy used in electronic materials including connectors. CONSTITUTION: Cu-Ni-Si alloy is characterized in that compression residual stress of 20 to 200 MPa exists on the surface of the alloy as a copper alloy containing 1.0 to 4.5 mass% of Ni, 0.2 to 1.2 mass% of Si, and the balance being Cu and inevitable impurities, wherein the maximum valley depth(Rv) on the surface of the alloy is 1 μm or less, wherein the alloy has 100 or less of inclusions/mm¬2, the inclusions having diameter of 4 μm or more, and wherein the alloy contains 0.05 to 0.3 mass% of Mg, 0.01 to 0.5 mass% of P, 0.01 to 1.5 mass% of Sn, 0.01 to 1.5 mass% of Zn, and 1 mass% or less of one or more elements selected from Fe, Co, Cr, Zr, Ti, Ag, Mn and Al.