Home /
T.O.C.
FAQs
 
Good
Books
Ref.
Libr.
Advertise
Here
Help
Wanted
Current
Q&A's
Search 🔍
the Site
pub Where the world gathers for
plating, anodizing, & finishing Q&As since 1989





-----

Why do we have scratching on Zinc-Iron plating with black chromate?





2005

Need help with problem, tried everything but I am still getting scratching on the parts with zinc fe and black chromate with sealer; customer rejecting the scratching. How can I solve this problem or what is causing this issue
thamks

Mark Banspach
plating shop - Providence, R.I.



2005

First question is do you get scratching of sealer or chromate? Second: are parts chromated and sealed in barrels, baskets, racks, etc.? Third how are parts dryed and at what temperature? Fourth: How are parts handled and shipped?

Gene Packman
process supplier - Great Neck, New York



2005

Hi!

Try to increase Iron level in the bath to the highest level that is suggested from your supplier.
Analyze bath on carbonate, when it is over 80 gpl, than dilute the bath on half, or get rid of carbonate by cooling down the bath on 4-5°C. Carbonate (an also a lot of caustic) will pecipitate.

Dimitrij Us
- Kranj, Slovenija (EU)



2005

Dear Mark,
Check the pH of the black passivation bath and adjust as per suppliers manual. Use deionised water for rinses.
Please give more detailes about the process cycle you follow.
Good luck

t k mohan
T.K. Mohan
plating process supplier - Mumbai, India




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact    -    Privacy Policy    -    ©1995-2023 finishing.com, Pine Beach, New Jersey, USA