Abstract: To obtain a copper alloy having a tensile strength of 700 N/mm2 or more and a conductivity of 60% IACS or more, a copper alloy of the present invention comprises from 0.8 mass % to 1.8 mass % of Co, from 0.16 mass % to 0.6 mass % of Si, and the balance of Cu and unavoidable impurities, in which a mass ratio of Co to Si (Co/Si) is between 3.0 and 5.0; a size of inclusions to be precipitated in the copper alloy is 2 ?m or less; and a total volume of the inclusions having a size of between 0.05 ?m and 2 ?m in the copper alloy is 0.5 vol % or less.

Abstract: Raw materials for a copper alloy are melted in a high frequency smelter and cast, and milling, rolling, and annealing are carried out. Then, rolling is again carried out. Thereafter, the materials are heated at a temperature of 900° C. for one minute and are quenched in water, to be solution treated. Subsequently, the materials are heated at a temperature of 500° C. for five hours for aging, and then are cooled at a cooling rate in a range of 10 to 50° C. per hour until the materials are cooled to a temperature of 380° C.

Abstract: Raw materials for a copper alloy are melted in a high frequency smelter and cast, and milling, rolling, and annealing are carried out. Then, rolling is again carried out. Thereafter, the materials are heated at a temperature of 900° C. for one minute and are quenched in water, to be solution treated. Subsequently, the materials are heated at a temperature of 500° C. for five hours for aging, and then are cooled at a cooling rate in a range of 10 to 50° C. per hour until the materials are cooled to a temperature of 380° C.

Abstract: Raw materials for a copper alloy are melted in a high frequency smelter and cast, and milling, rolling, and annealing are carried out. Then, rolling is again carried out. Thereafter, the materials are heated at a temperature of 900° C. for one minute and are quenched in water, to be solution treated. Subsequently, the materials are heated at a temperature of 500° C. for five hours for aging, and then are cooled at a cooling rate in a range of 10 to 50° C. per hour until the materials are cooled to a temperature of 380° C.

Abstract: To obtain a copper alloy having a tensile strength of 700 N/mm2 or more and a conductivity of 60% IACS or more, a copper alloy of the present invention comprises from 0.8 mass % to 1.8 mass % of Co, from 0.16 mass % to 0.6 mass % of Si, and the balance of Cu and unavoidable impurities, in which a mass ratio of Co to Si (Co/Si) is between 3.0 and 5.0; a size of inclusions to be precipitated in the copper alloy is 2 ?m or less; and a total volume of the inclusions having a size of between 0.05 ?m and 2 ?m in the copper alloy is 0.5 vol % or less.

Abstract: Raw materials for a copper alloy are melted in a high frequency smelter and cast, and milling, rolling, and annealing are carried out. Then, rolling is again carried out. Thereafter, the materials are heated at a temperature of 900° C. for one minute and are quenched in water, to be solution treated. Subsequently, the materials are heated at a temperature of 500° C. for five hours for aging, and then are cooled at a cooling rate in a range of 10 to 50° C. per hour until the materials are cooled to a temperature of 380° C.

Abstract: The present invention provides a copper alloy for electronic part which is excellent in adhesion of silver(Ag) and reliability of solderability and adhesion of plating without impairing excellent strength and electrical conductivity of a copper-nickel-silicon alloy. The copper alloy for electronic parts in the present invention consist essentially of 1.7 to 4.0% by weight of nickel, 0.3 to 0.8% by weight of silicon, 0.002 to 0.3% by weight of silver, 0.5 to 2.0% by weight of zinc, and a residual of copper.