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Level 2 layer of passivation
March 14, 2013
I recently came across thru plating quality declaration of renowned organization stating, they have improved their plating quality to level-2 by changing "Zinc blue Passivation" to "Zinc Yellow Passivation"
I understood that Yellow passivation is RoHS compliant & best corrosion resistance , but not aware about level-2 of passivation.
Please guide what are the levels of passivations and how Yellow Zinc Passivation is level 2 passivation.
Design Engineer - Pune, India
A. Hi cousin Madhav. I could be wrong, but I think you are in the situation of improperly stringing words together that you are hearing or reading from various sources :-)
I doubt that there is any universal quality standard, "Level-2" , which represents a higher level of quality than "Level-1" although I suppose it's vaguely possible for a given individual organization to sell screws of "Level-1" quality to house builders and "Level-2" to aircraft companies.
Is there any chance that "Level-2" simply refers to level-2 documents within their quality control system, and you have misinterpreted it?
To be RoHS-compatible, chromate conversion coatings must be trivalent, whether they are blue or yellow. In the old days of hexavalent chromate conversion coatings, yellow coatings generally were "better" because they contained more hexavalent chrome. In the case of trivalent RoHS-compatible conversion coatings, the color is as likely to just be dye, so it is not true that yellow coatings are better than blue ones.
Ted Mooney, P.E.
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