Metal finishing Q&As since 1989

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Clear anodize vs. clear chromate in light duty work

 

My company specs clear anodize finish on several machined or sheet metal aluminum components (typically 6061-T6 or 5052-H32). We often call out holes that must free of finish to maintain electrical contact between a PC board and the ground plane.

Recently a vendor suggested clear chromate as an electrically conductive alternative to clear anodize, thus saving the cost of plugging holes.

In a light duty industrial environment (electronics assembly) that requires 5+ years durability, good appearance (no yellowing) and corrosion resistance, is clear chromate an acceptable alternative to clear anodize?

Patrick Simpson
- Rochester, New York

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If you could substitute, and it is very possible that you might, you would save a lot more than the cost of plugging the holes.

  
Tom Pullizzi
Falls Township, Pennsylvania
 

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This is a very tough one to answer: the problem being that the corrosion resistance of clear chromate doesn't even compare with anodizing, and 5 years is a long time, and mileage may vary. So there will surely be at least one customer who finds the substitution unsatisfactory.

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