Patent ID: 8524376

Claim:
A Sn-plated Cu-Zn alloy strip in which generation of whiskers is suppressed, wherein a copper alloy containing 15 to 40 mass % of Zn in terms of an average concentration is used as an alloy strip, layers of an Sn phase, an Sn—Cu alloy phase and an Ni phase constitute a plating film in that order from an outer surface of the plating film to the alloy strip, and the Zn concentration of the outer surface of the Sn phase is in a range of 0.1 to 5.0 mass % and wherein the layers are formed by: Ni plating in a thickness of 0.1 μm or more, and then performing Cu plating in a thickness of 0.1 μm or more (provided that the total of the Ni plating thickness and the Cu slating thickness is in a range of 0.3 to 1.0 μm); Sn plating in a thickness of 0.3 to 1.0 μm; and a reflow treatment for heating time t (seconds) and at a heating temperature T (°C.) represented by the following three equations: 5≦t≦23, 350≦T≦600, and 500≦( T +14 t )≦670.