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Chipoff in zn-fe alloy black passivation

Is zn-iron alloy system is highly brittle. I have Zn-Fe system which has a peculiar problem. In HCD areas, the non-silver black passivation gets chipped off. help me in this regard.

Thank you,

Jude
Industrialist - Coimbatore, Tamil Nadu, India
2004

Ed. note: full name please, Jude.

Jude

It is entirely possible the parts are burning in Zinc Iron Plating because of low caustic or lo metal. Or the edges are too close to the anode because the bath is incorrectly sized for the component. Min distances are 5 to 6 inches for 40 ASF average Cathode CD. Provided there is sufficient basic chemical in solution ? You need to have your supplier look at the solution. Analyse the bath , check the additive levels and possibly a reduction of anode area could be necessaryy. Post plate Rinsing and activation aspects need validation. Do you have a flowing water rinse after plating ? Have a trained Plating chemist work this out for you.Hands on aspects will decide this issue..

Regards,

Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
2004