COPPER ALLOY HAVING EXCELLENT STRESS RELAXATION PROPERTY

Abstract

A Cu—Ni—Sn—P alloy is provided, which is excellent in stress relaxation property in a direction perpendicular to a rolling direction, and has any of high strength, high conductivity, and excellent bendability. A copper alloy contains 0.1 to 3.0% of Ni, 0.1 to 3.0% of Sn, and 0.01 to 0.3% of P in mass percent respectively, and includes copper and inevitable impurities as the remainder; wherein in a radial distribution function around a Ni atom according to a XAFS analysis method, a first peak position is within a range of 2.16 to 2.35 Å, the position indicating a distance between a Ni atom in Cu and an atom nearest to the Ni atom. Thus, distances to atoms around the Ni atom in Cu are comparatively increased, so that the stress relaxation property in a direction perpendicular to the rolling direction of the copper alloy is improved.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an explanatory view showing a radial distribution function around a Ni atom measured by the XAFS analysis method of a copper alloy;

FIG. 2 is a schematic view showing an atomic arrangement condition assuming that only one Ni atom exists in copper;

FIGS. 3A to 3B are cross sectional views illustrating a stress-relaxation resistance test of a copper alloy sheet; and

FIGS. 4A to 4B show a structure of a box-like connector, wherein FIG. 4A is a side view, and FIG. 4B is a cross sectional view.

Claims

1. A copper alloy having excellent stress relaxation property comprising 0.1 to 3.0% of Ni, 0.1 to 3.0% of Sn, and 0.01 to 0.3% of P in mass percent respectively, and the remainder being copper and inevitable impurities, wherein in a radial distribution function around a Ni atom according to a XAFS analysis method, a first peak position is within a range of 2.16 to 2.35 Å, the position indicating a distance between a Ni atom in Cu and an atom nearest to the Ni atom.

2. The copper alloy having excellent stress relaxation property according to claim 1, wherein the copper alloy further comprises 0.5% or less of Fe, 1% or less of Zn, 0.1% or less of Mn, 0.1% or less of Si, and 0.3% or less of Mg in mass percent.

3. The copper alloy having excellent stress relaxation property according to claim 1, wherein the copper alloy further comprises at least one element selected from the group consisting of Ca, Zr, Ag, Cr, Cd, Be, Ti, Co, Au and Pt, and a total content of the element is 1.0% or less in mass percent.

4. The copper alloy having excellent stress relaxation property according to claim 2, wherein the copper alloy further comprises at least one element selected from the group consisting of Ca, Zr, Ag, Cr, Cd, Be, Ti, Co, Au and Pt, and a total content of the element is 1.0% or less in mass percent.

5. The copper alloy having excellent stress relaxation property according to claim 1, wherein the copper alloy further comprises at least one element selected from the group consisting of Hf, Th, Li, Na, K, Sr, Pd, W, S, C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As, Sb, Bi, Te, B and mish metals, and a total content of the elements is 0.1% or less in mass percent.

6. The copper alloy having excellent stress relaxation property according to claim 2, wherein the copper alloy further comprises at least one element selected from the group consisting of Hf, Th, Li, Na, K, Sr, Pd, W, S, C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As, Sb, Bi, Te, B and mish metals, and a total content of the elements is 0.1% or less in mass percent.

7. The copper alloy having excellent stress relaxation property according to claim 3, wherein the copper alloy further comprises at least one element selected from the group consisting of Hf, Th, Li, Na, K, Sr, Pd, W, S, C, Nb, Al, V, Y, Mo, Pb, In, Ga, Ge, As, Sb, Bi, Te, B and mish metals, and a total content of the elements is 0.1% or less in mass percent.