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US 4,474,626 AGranted
Solution and process for the chemical conversion of metal substrates
AssigneeRoquette Freres
InventorsJean-Claude Lumaret, Serge Gossett, Didier Boulinguiez
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Abstract
Acid solution for the chemical conversion of metallic substrates, comprising: a polyphosphate, soluble in water and of the formula (X PO.sub.3).sub.n in which n.gtoreq.3 and in which X is an alkali, alkaline earth metal or ammonium, an organic chelating agent and the zinc ion, the pH being brought to the desired value by means of an inorganic acid selected from the group comprising sulphuric hydrochloric and nitric acid.
Claims21
Acid solution for the chemical conversion of metallic substrates, comprising:
- at least 0.2 m moles per liter of a polyphosphate, soluble in water and of the formula (X PO.sub.3).sub.n in which n.gtoreq.3 and in which X is an alkali, alkaline earth metal or ammonium,
- at least 0.3 m moles per liter of an organic chelating agent and
- at least 0.15 of qt.-g the zinc ion, the pH being brought to the desired value by means of an inorganic acid selected from the group comprising sulphuric hydrochloric and nitric acid.
Dependencies are inferred from the claim text.