46035

Can't get jet black passivation on Zinc-nickel plated parts [India] 

August 6, 2007

My customer spec. is to have jet black passivation, whereus our process that produces brownish tint with black colour after passivation. What is possible remedy to get jet black colour..

Parthasarathy
Manager - Chennai, Tamil Nadu, India


August 6, 2007

Does it absolutely have to be zinc-nickel? I think you'll find that a reliable black is a lot easier if the plating is zinc-iron.


Ted Mooney, P.E. 
finishing.com
Brick, NJ


August 8, 2007

Hai!
In your letter there is no clear picture about plating. The sustrate should be Zinc(acid) plated, followed by nickel plating. Then the thickness sholud be more than 20 micron. If the substrate plated like that u can achieve the desire colour.
GOOD LUCK

P.KARTHIKEYAN
- Bangalore, Karnataka, India.


August 10, 2007

Please verify with your chemical supplier latest development in trivalent chromates will help you to achieve with 80 to 90% Jet black finish (aceptable level)

P. Gurumoorthi
    electroplating process chemicals
Chennai, Tamilnadu, India



August 10, 2007

Parthasarathy,
Please give more detailes about your customer spec. and also full detailes of what is your plating process.There are lots of developments happening in Zinc plating.
Alkaline cyanide free Zinc iron plating, followed by trivalent passivation is the answer.If u come out with more detailes, u will get good suggestions.
p.S. It is nice to see Gurumoorthi back!
Regards

T.K. Mohan
    plating process supplier 
Mumbai, India


September 28, 2007

Dear Mr Parthasarathy,

Try doing an XRF analysis of the Nickel - Zinc percentages on the parts that dont look so good with black. You may find that they have a higher percentage of Nickel in them
and you may have to increase 2-3% of Zinc in the plated alloy to get a pleasing black.

Khozema Vahanwala
Automaxx
 
Bangalore, Karnataka, India








     

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