To obtain a surface-treated metal plate which shows good corrosion resistance and good electromagnetic wave-shielding property in a frequency range of 30-1,000 MHz, and a package for an electronic device.
The surface-treated metal plate excellent in electromagnetic wave-shielding property includes: a Zn lower plating layer which has Zn content of 92-100 mass% and is deposited in an amount of 0.5-50 g/m2 per surface; a Zn-Ni upper plating layer which has a value obtained by dividing the X ray diffraction intensity of a peak at a position corresponding to d/n value (wherein d is a crystal lattice spacing; and n is a natural number) of 0.1125 nm but 0.1145 nm by the X ray diffraction intensity of a peak at a position corresponding to d/n value of 0.1120 nm but 0.1125 nm of 0.5 and is deposited in an amount of 0.5-50 g/m2 per surface; and a chemical conversion coating film having average film thickness of 0.4-4.0 m on at least a portion of the upper plating layer.
NAKAZAWA MASATO
Takashi Ishida
Tetsuji Koga
Hiroshi Kamematsu
Nakamura Asayuki
Nagasaka Tomoyasu
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