Cu-Ni-Si-Co-Cr System Alloy for Electronic Materials

Abstract

The problem to be solved by the present invention is to provide a significant improvement in the properties in Cu—Ni—Co—Si alloy by adding Cr, i.e., to provide Corson alloys having high strength and high electrical conductivity. There is provided a copper alloy for electronic materials comprising 1.0 to 4.5 mass % of Ni, 0.50 to 1.2 mass % of Si, 0.1 to 2.5 mass % of Co, 0.003 to 0.3 mass % of Cr, with the balance being Cu and unavoidable impurities, the mass concentration ratio of the total mass of Ni and Co to Si ([Ni+Co] / Si ratio) satisfies the formula: 4≦[Ni+Co] / Si≦5, and with regard to Cr—Si compound whose size is 0.1 to 5 μm dispersed in the material, atomic concentration ratio of Cr to Si in the dispersed particle is 1-5, and area dispersion density thereof is more than 1×104 / mm2, and not more than 1×106 / mm2.

Description

TECHNICAL FIELD

[0001] The present invention relates to precipitation hardening copper alloys, in particular, to Cu—Ni—Si—Co—Cr system alloys suitable for use in a variety of electronic components.BACKGROUND ART

[0002] A copper alloy for electronic materials that are used in a lead frame, connector, pin, terminal, relay, switch, and various other electronic components is required to satisfy both high strength and high electrical conductivity (or thermal conductivity) as basic characteristics. In recent years, as high integration and reduction in size and thickness of an electronic component have been rapidly advancing, requirements for copper alloys used in these electronic components have been increasingly becoming severe.

[0003] Recently, because of considerations related to high strength and high electrical conductivity, the amount in which precipitation-hardened copper alloys are used has been increasing, replacing conventional solid-solution strengthened copper alloys typified by pho...