| 摘要 |
<p>A ferrous metal sheet has, on its surface, a Zn-Al alloy continuous hot-dip coating comprising, by wt., 0.2-17% Al, 0.02-0.15% Sb, max. 0.02% Pb, bal. Zn. The coating is applied by continuously passing the sheet through a hop-dip coating bath contg. the alloy compsn.. The metal sheet is pref. clean and free of surface oxides when immersed in the bath and is passed between jets of blowing gas as it is continuously withdrawn from the bath. The Sb addn. in the bath reduces the surface tension of the molten alloy compsn. so that a smooth, bright, ripple-free coating is formed. The coating is resistant to intergranular corrosion and blistering along grain boundaries when exposed for prolonged periods to a high humidity atmos., and the coating is formable without having to be separate from the sheet.</p> |
