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1st vs. 2nd vs. 3rd Generation Trivalent Passivation

What is the major difference between Ist/IInd/IIIrd generation trivalent passivation. What does DIN 50021/ISO 9227 [salt spray]test say with respect to the protection hours for white and red rust for these generation.

Gaurav Misra
buyer - India
June 25, 2008

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Hi, Gaurav. There may be a widely recognized and agreed-to meaning for first, second, and third generation trivalent passivation, but I doubt it. Usually "new generation" and "next generation" are the wording of sales pap rather than learned technical papers, but I stand to be corrected on that.

Sorry, I don't understand your second question. I don't have that standard on hand, but I'd be reluctant to selectively quoting it anyway because it leads to people thinking that they are working to spec when they are actually working to second and third-hand misunderstandings of a spec :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
June 25, 2008

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Hi Ted

Thank you for the information. Well we have being getting our steel strips zinc plated of course trivalent passivation. It was the rack plating, thick film passivation [This is achieved using an adapted form of process control, and a higher concentration of Cr(III) and cobalt-based inhibitors in the preparation solution. Thick layer passivations are separated into layer thicknesses of > 250 nm.] For which we are getting 120/240 hrs of white/red rust as per DIN 50021ss.

Now a new supplier introduce us to the Ist/IInd/IIIrd generation plating technique (probably a Japanese one, please see the publish paper from [deleted by editor])

Now we are little confused as what exactly is? And what is the difference between them.

Gaurav Misra
- INDIA
June 27, 2008

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Hi, Gaurav. Please ask your old supplier to comment on this paper by the new supplier. And ask your peers in the local plating associations for their experiences. As previously mentioned, concepts like 2nd generation and 3rd generation, and so on, tend to be more sales talk than clearly identifiable and universally agreed upon technical milestones.

I don't feel it's appropriate for this site to print a proprietary paper like this and invite their competitors to take public pot shots at it. Considering the anonymity of the internet, and the impracticality of investigating vested interests, it couldn't possibly end well :-)

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 6, 2008