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What Fluoride Concentration is used in Zinc Phosphate solutions for steel?

Do zinc phosphate solutions for finishing steel parts typically contain fluoride? If so what is the approximate concentrations?

Tom Mort
- Grand Rapids, Michigan
2002

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2002

Hi,

Fluoride is not normally required for steel phosphates, but may well be present to allow processing of non-ferrous metals and make the process "more aggressive" on some steels. If fluoride is present it would be typically in the range 0.5-1.5 g/l. It could be present as F only or as SiF6, BF4 or a combination of these.

Hope this helps,

Roger Bridger
- Croydon, UK

To my knowledge, no, the phosphating bath as such does not include fluorides. But some phosphating systems use a [potassium-Titanium Fluoride] in the previous rinse tank, which works as a metal activator for the phosphate crystal build up.

Vijay Subramanian
- Ann Arbor, Michigan   
2002