| 摘要 |
Provided is a copper alloy sheet having both high strength property and highly reduced flexural bending coefficient property at high level. The second phase particles existed in the parent phase of the Cu-Ni-Co-Si based copper alloy sheet according to the present invention comprises ultra fine second phase particles having particle diameter equal to 2 nm or smaller than 10 nm and density equal to or more than 1.0x10^9 particles/mm^2, fine second phase particles having particle diameter equal to 10 nm or smaller than 100 nm and density equal to or more than 5.0x10^7 particles/mm^2, and coarse second phase particles having particle diameter equal to or bigger than 100 nm and equal to or smaller than 30 μm and density equal to or more than 1.0x10^5 particles/mm^2 and equal to or less than 1.0x10^6 particles/mm^2. The ratio I{200}/I_o{200} of an integral intensity I{200} of X-ray diffraction peak at {200} crystal plane of a surface of the relevant copper alloy sheet to an integral intensity I_o{200} of X-ray diffraction peak at {200} crystal plane of a standard pure copper powder specimen is equal to or more than 3.0. |
