Abstract: A Cu—Co—Si alloy having an improved balance between electrical conductivity and strength is provided. Disclosed is a copper alloy for electronic materials, which contains 0.5% to 4.0% by mass of Co and 0.1% to 1.2% by mass of Si, with the balance being Cu and unavoidable impurities, and in which the mass % ratio of Co and Si (Co/Si) is 3.5?Co/Si?5.5, an area ratio of discontinuous precipitation (DP) cells is 5% or less, and an average value of a maximum width of discontinuous precipitation (DP) cells is 2 ?m or less.

Abstract: A Cu—Co—Si-based alloy that has even mechanical properties and that is provided with favorable mechanical and electrical properties as a copper alloy for an electronic material is provided. The copper alloy for an electronic material comprises 0.5% by mass to 3.0% by mass of Co, 0.1% by mass to 1.0% by mass of Si, and the balance Cu with inevitable impurities. An average grain size is in the range of 3 ?m to 15 ?m and an average difference between a maximum grain size and a minimum grain size in every observation field of 0.05 mm2 is 5 ?m or less.

Abstract: A Cu—Co—Si alloy having an improved balance between electrical conductivity and strength is provided. Disclosed is a copper alloy for electronic materials, which contains 0.5% to 4.0% by mass of Co and 0.1% to 1.2% by mass of Si, with the balance being Cu and unavoidable impurities, and in which the mass % ratio of Co and Si (Co/Si) is 3.5?Co/Si?5.5, an area ratio of discontinuous precipitation (DP) cells is 5% or less, and an average value of a maximum width of discontinuous precipitation (DP) cells is 2 ?m or less.

Abstract: The present invention provides Cu—Co—Si system alloys that have desirable mechanical and electrical characteristics as a copper alloy for electronic materials, and have uniform mechanical characteristics. The copper alloys for electronic materials contain 0.5 to 4.0 mass % Co, 0.1 to 1.2 mass % Si, and the balance being Cu and unavoidable impurities. An average grain size is 15 to 30 ?m and an average difference between maximum grain size and minimum grain size in every observation field of 0.5 mm2 is not more than 10 ?m.