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Is anodizing or chromate conversion coating better under powder coating

1998

I am trying to find answers to the following questions:

1. Is the adhesion of powder coatings on aluminum improved by anodize or Alodine treatment before coating?
2. If there is an improvement, is there a significant difference between the two treatments?

I also would like to know, in simple terms, what the difference is between anodize and Alodine.

Can any of your readers help?

Marshall Davidson
- Meriden Connecticut

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Alodine is a brand name for a process which is generically called chromate conversion coating. These coatings are electrically conductive and corrosion resistant but with almost no abrasion resistance.

Anodize is an electrochemical process which converts the surface aluminum into aluminum oxide. It is non-conductive with significant corrosion and abrasion resistance.

Both coatings are widely used as adhesion promoters. However, some post treatments can cause adhesion problems. Make sure your finisher knows the final application. Generally, chromate conversion coatings are less expensive than anodize, while anodizing offers better protection.

Chris Jurey, Past-President IHAA
Luke Engineering & Mfg. Co. Inc.

Wadsworth, Ohio

1998

what is the different between aluminum anodized and aluminum powder coated

hosam m
guest - k.s.a.
July 13, 2009

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Hi, Hosam. Anodizing has been described; if the description leaves you with any questions, please let us know.

Powder coating is very similar to painting in final results and appearance. Rather than the solids of the paint being dissolved into water or solvent, the solids are supplied as a powder. The powder particles are sprayed onto the part, and electrostatic attraction keeps them there. Then the part goes into an oven where the powder melts and fuses into a continuous thin sheet.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Ted is available for instant help
or longer-term assistance.
July 13, 2009

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