Metal finishing Q&As since 1989

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Sealing problem after anodising

In the anodising plant, Hard anodised aluminium components are not properly sealed even after soaking in nickel acetate - de mineralised water solution for a hour at 70 °C. What are reasons?

Rajaram
anodiser - Mumbai City, Maharastra state, India
2006

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There could be a number of causes, including contaminated or weakened seal, too large of a poor size, a powdery coating to begin with...

But, the most likely one is that you should turn up the heat a bit... try running above 95 C.

Good luck!

Jim Gorsich
Compton, California, USA
2006

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Unless you are using a "cold seal" or a "mid temp seal" Your Ni seal should operate between 140 and 170 F

you can also try soaking rinsed parts in hot DI water after the seal. When I say hot I mean 200+ degrees.

this will ensure the hydration of the anodic coating.

Ryan Cook
Toccoa, Georgia
2006