METHOD OF MANUFACTURE OF PHOSPHATE COATING Russian patent published in 2009 - IPC C23C22/22 

FIELD: metallurgy.

SUBSTANCE: invention relates to protection of metals against corrosion and is designed for a preliminary treatment of the metal surface for the follow-up paint application. The method involves phosphatisation of the metal surface in the aqueous solution and this is performed by spraying the aqueous solution on the metal surface for 40-60 sec at the point of entry into the phosphatisation tank by immersing the metal into the phosphatisation tank for 2.5 min and spraying the aqueous solution on the metal surface for 40-60 sec at the output of the phosphatisation tank with temperature of the aqueous solution being 35 - 40°C and the aqueous solution containing, g/l: Zn²⁺ 1.90 - 4.32, P₂O₅ 4.82 - 10.48, NO₃ ^- 0.64 - 1.64, ClO₃ ^- 0.16 - 0.44, Ca²⁺ 1.14 - 1.73, Mn²⁺ 0.06 - 0.16, F^- 0.19 - 0.38, hydroxylamine hydrosulphate 0.02 - 0.08, and correlation of the cation sum (Zn²⁺+Ca²⁺+Mn²⁺) to P₂O₅ is (0.666 - 1.334): (1.035 - 2.251).

EFFECT: method enables to produce microcrystalline corossion-resistant phosphate coating by a combined method of the phosphatisation nickel-free aqueous solution with reduced phosphatisation time.

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