Cu-Ni-Si-based copper alloy plate, Cu-Ni-Si-based copper alloy plate with plating film, and manufacturing method thereof

摘要

PROBLEM TO BE SOLVED: To improve electrical connection reliability in a high temperature environment in a Cu-Ni-Si-based copper alloy plate containing Ni and Si, and to obtain a Cu-Ni-Si-based copper alloy plate with a plating film such as Sn. Even in this case, it enhances electrical connection reliability, solder wettability and adhesion of the plating film in a high temperature environment. SOLUTION: In the central portion in the plate thickness direction, Ni of 0.4% by mass or more and 5.0% by mass or less and Si of 0.05% by mass or more and 1.5% by mass or less are contained, and the balance is Cu and unavoidable. A copper alloy plate made of target impurities, the Ni concentration on the plate surface is 70% or less of the bulk Ni concentration at the center of the thickness, and the plate surface has a depth of 90% of the bulk Ni concentration. It has a surface layer portion, and the Ni concentration increases in the surface layer portion from the plate surface toward the center of the thickness with a concentration gradient of 5.0% by mass / μm or more and 100% by mass / μm or less. [Selection diagram] Fig. 2