| 摘要 |
<p>A plated steel sheet having improved corrosion and heat resistances is produced by supplying chromium to an Al-Si plating layer formed on the surface of a steel sheet by hot dipping. The chromium source to be used comprises a chromium coating layer formed on the surface of a nonplated sheet by electroplating, vacuum deposition, etc. The wettability of the chromium coating layer with a plating metal can be improved by activating the surface of the layer by plasma etching, ion beam etching, etc., before dipping a chromium-coated steel sheet in a hot dipping bath. The plating layer L formed on the steel substrate S has a layered structure composed of the first layer L1 based on chromium, the second layer L2 based on Cr-Al-Si system and the third layer L3 based on Al-Si-Cr system, when plating is conducted under the conditions of a thick chromium coating layer and a relatively suppressed diffusion of chromium. Since the plating layer L contains chromium, the resultant plated steel sheet is far more excellent in corrosion and heat resistances than the conventional Al-Si-plated steel sheets.</p> |
