BLACK STEEL SHEET EXCELLENT IN ELECTROMAGNETIC WAVE SHIELDING PROPERTY, ELECTROMAGNETIC WAVE SHIELDING MEMBER AND ELECTROMAGNETIC WAVE SHIELDING CASE

摘要

A black steel sheet which has a Zn-Ni plated steel sheet having a blackening treatment layer and a coating layer formed on the surface thereof, characterized in that said blackening treatment layer has a thickness of 0.01 to 1.0 μm, and said Zn-Ni plated steel sheet having a blackening treatment layer has a surface roughness wherein the arithmetic average roughness (Ra) is 0.7 to 20 μm and the number of peaks per inch (PPI) is 180 or more.