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-----Need info about yellow dye to be used with passivation
I like to know whether a yellow dye can be used in combination with Trivalent blue passivation to obtain a yellow finish after Zinc plating? Can it be mixed with the passivate and used? If so Pl also say me the type of dye that has to be used and where to get it?
Rajan- Gurgaon, Haryana, India
+++
2003
Sorry Chief,
No such product exists. This is like the story of people using Robin blue fabric dye in Chrome tanks to get a blue on the chrome.
Khozem Vahaanwala
Saify Ind
Bengaluru, Karnataka, India
2003
Mr Rajan
QA and QC heads world wide accept blue trivalent coatings provide 120 SST hours. This has been done over 3 years ago.
The yellow color is a non functional cosmetic hangup that has to be relegated to the dark ages.
I suggest you look at functional characteristics of the trivalent coating as the primary route to moving towards removal of Hex coatings.
Some companies do have a 2 step trivalent which produces a " Yellow look ". The SST hours don't improve over blue. But it shows a yellowed look.
Incidentally, when trivalent Chromates show a yellow look , its a visual confirmation the coating has Hexavalent chrome in it.
Asif Nurie [deceased]
- New Delhi, India
With deep regret we sadly advise that Asif passed away on Jan 24, 2016
2003
The yellow color is a non functional cosmetic hangup that has to be relegated to the dark ages.
Thank you for that, Mr. Nurie! It drives me bonkers that people are bound & determined to insure that the new "green" trivalent chromates will look exactly like the old toxic hexavalent chromates--so that when the time comes that it is necessary to separate them it will be just all that much harder :-)
Ted Mooney, P.E.
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