Copper alloy for electrical and electronic equipment, copper alloy thin sheet for electrical and electronic equipment, and conductive component and terminal for electrical and electronic equipment

Abstract

Provided is a copper alloy for electrical and electronic equipment, having reliable and sufficiently excellent copper alloy stress relaxation properties and having excellent strength and bending workability. Also provided are a copper alloy thin sheet for electrical and electronic equipment and a conductive component and a terminal for electrical and electronic equipment. The copper alloy for electrical and electronic equipment contains more than 2 mass% but less than 23 mass% Zn, 0.1-0.9 mass% Sn, at least 0.05 mass% but less than 1.0 mass% Ni, at least 0.001 mass% but less than 0.10 mass% Fe, and 0.005-0.1 mass% P, with the remainder being Cu and unavoidable impurities. The copper alloy for electrical and electronic equipment fulfills, by atomic rate, 0.002<=Fe/Ni<1.5, 3<(Ni+Fe)/P<15, and 0.3<Sn/(Ni+Fe)<5. The special grain boundary length ratio (L<sigma>/L), being the ratio between the sum (L<sigma>) of each grain boundary length for [Sigma]3, [Sigma]9, [Sigma]27a, and [Sigma]27b and length (L) of all crystal grain boundaries is at least 10%.

Description

technical field [0001] The present invention relates to a Cu-Zn-Sn series copper alloy for electrical and electronic equipment used as a connector of a semiconductor device, other terminals, a movable conductive sheet of an electromagnetic relay, or a conductive element for an electrical and electronic equipment such as a lead frame, and its use The copper alloy thin plate for electronic and electrical equipment of the copper alloy for electronic and electrical equipment, a conductive element and a terminal for electronic and electrical equipment. [0002] This application claims priority based on Patent Application No. 2013-055076 for which it applied in Japan on March 18, 2013, and uses the content here. Background technique [0003] Cu—Zn alloys have conventionally been widely used as the above-mentioned conductive elements for electronic and electrical equipment from the viewpoints of strength, workability, cost balance, and the like. [0004] In addition, in the case o...

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Problems solved by technology

[0016] However, in Patent Documents 1 and 2, only the individual contents of Ni, Fe, and P are considered, and it is not always possible to reliably and sufficiently improve the stress relaxation resistance of copper alloys only by adjusting these individual contents.

[0017] In addition, although Patent Document 3 discloses adjusting the Ni / Sn ratio, the relationship between the P compound and the stress relaxation resistance is not considered at all, and it is impossible to achieve a sufficient and reliable improvement of the stress relaxation resistance of the copper alloy.

[0018] Furthermore, in Patent Document 4, the stress relaxation resistance of the copper alloy cannot be sufficiently improved only by adjusting the total amount of Fe, Ni, and P and the atomic ratio of (Fe+Ni) / P.

[0019] As described above, conventionally proposed methods cannot sufficiently improve the stress relaxation resistance of Cu-Zn-Sn-based alloys and copper alloys.

Therefore, in the connector of the above-mentioned structure, the residual stress relaxes over time or in a high-temperature environment, and the contact pressure with the conductive member on the opposite side cannot be maintained, so that there is a problem that defects such as poor contact are likely to occur at an early stage.

In order to avoid this problem, in the past, the wall thickness of the material had to be increased, resulting in an increase in material cost and weight

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