sstjacque

Re: Duplex Seal

Can anyone tell me about Duplex Seal? I work for a manufacturing company that requests on thier drawings that the Sulfuric Anodizing to have a Duplex seal. Does anyone have any information on this seal? Is there a Mil spec or equivalent for it?
Thanks for any help.

LeoH

Re: Duplex Seal

A duplex seal is a nickel acetate seal followed by a hot water seal.  It gives a better seal in less time.

DustinGebhardt

Re: Duplex Seal

I've never heard of or used this process before, so I'm curious about it.  I'm assuming that the nickel acetate seal is a mid-temp seal, followed by a high-temp DI seal.  Would it be possible to increase the temp in the nickel acetate to the same temperature of the DI seal and achieve the same result but in only 1 tank/step?

-Dustin Gebhardt, CEF

Advanced Manufacturing/Finishing Engineer

Moen

Sanford, NC

LeoH

Re: Duplex Seal

Anodize hydrates faster and more thoroughly at temperatures near boiling but nickel acetate seals have problems with the stability of the dispersant and smutting at these temperatures.  Using both therefore offers better sealing faster, the best of both methods.  Kinda like having your cake and eating it too.

Metalman

Re: Duplex Seal

How can one verify that Na-or-K-dichromate sealing has been done on an aluminum die casting?  I have analyzed the surface using EDS and no chromium is detected.  The nickel from the nickel acetate shows up.  Can EDS analysis typically detect chromium on a dichromate sealed anodize?

AluConsult

Re: Duplex Seal

Hi

About the dichromate seal, you should be able to find chrome in your EDX analysis after the sealing and it will show up kind of yellowish.

Sunny regards

Anne

www.anodizingworld.com