| 摘要 |
<p>A chromium-free water-based surface treatment liquid which contains from 0.01 to 50 g/l of a total of dissolved manganic acid, permanganic acid, and salt(s) thereof and from 0.01 to 20 g/l of a total of dissolved titanium compounds and has a pH of from 1.0 to 6.0 reacts rapidly with aluminum and aluminum alloy surfaces to deposit thereon a protective coating that does not contain hexavalent chromium and has excellent corrosion resistance and paint film holding properties.</p> |
