| 摘要 |
(A) An iron phosphate conversion coating is formed on a metal surface by spraying the surface for 0.5-3 mins. with an aqueous solution containing 5-20 g/l sodium acid phosphate(I), 3-12 g/l NaClO3 (II) and 0.75-3 g/l hydroxylamine sulphate (III) at 32.2-54.4 ≦̸C. (B) An iron phosphate coating is formed on a ferrous metal surface by treating it with an aqueous solution containing 7.5-15 g/l (I), 5-10 g/l oxidising agent, pref. (II) and 1.5-2 g/l (III). The solution is kept at pH 4. 5-5.5. The method is suitable for five-stage phosphating of steel, using strong alkaline precleaning of the surface and a final rinse using partially reduced chrome.
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