| 摘要 |
PROBLEM TO BE SOLVED: To provide a surface treated metal sheet which can be suitably used for the enclosure of an electronic device, and is excellent in electromagnetic wave shieldability in the joint part. SOLUTION: The surface treated metal sheet has on one or both surfaces thereof a film containing granular nickel. When the average film thickness of the film is defined as t (μm), the grain size of the nickel is defined as R<SB>Ni</SB>and the distribution width of a 20% frequency level when the height of the peaks of the number-size distribution of the nickel is 100% is defined as W<SB>20</SB>(μm), the surface treated metal sheet satisfies conditions wherein: the peaks of the number-size distribution are present at least in the range of 1<[R<SB>Ni</SB>/t]≤2; the W<SB>20</SB>of the peaks of the number-size distribution is≤5; the peaks of the number-size distribution are not present in the range of 2<[R<SB>Ni</SB>/t]; and the number of the nickel present in the range of 2<[R<SB>Ni</SB>/t] is <5×10<SP>9</SP>per m<SP>2</SP>. By this constitution, the surface treated metal sheet has excellent electromagnetic wave shieldability in the joint part. COPYRIGHT: (C)2010,JPO&INPIT |
