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US 2009/0071573 A1Published application
Phosphating solution with hydrogen peroxide and chelating carboxylic acids
OwnerJan-Willem Brouwer, Jerzy-Tadeusz Wawrzyniak +2inventors
InventorsJan-Willem Brouwer, Jerzy-Tadeusz Wawrzyniak, Jens Kroemer, Maximilian Schoenherr
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Abstract
The invention relates to a phosphating solution and a process for the phosphating of metallic surfaces with aqueous, acidic phosphating solutions that comprise zinc and phosphate ions, at least one source of peroxide and one or more aliphatic chelating carboxylic acids containing 2 to 7 carbon atoms; the phosphating solution having a free acid content of one point or less.
Claims20
An acidic, aqueous phosphating solution comprising:
- a.) 0.2 to 3 g/l zinc(II) ions;
- b.) 3 to 50 g/l phosphate ions, calculated as PO4−3;
- c.) a source of hydrogen peroxide present in an amount sufficient to provide 15 to 50 g/l hydrogen peroxide in said solution;
- and
- d.) 0.3 to 1.5 g/l of one or more aliphatic chelating carboxylic acids containing 2 to 7 carbon atoms;
- said phosphating solution having a free acid content of one point or less.
3 more elements
Dependencies are inferred from the claim text.