Letter 40069

ASTM spec for yellow chromate adhesion testing  

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I'm in the process to document procedures to test yellow chromate plating in our facility.
I have read ASTM B-633 [link is to spec at TechStreet] and B571-97 [link is to spec at TechStreet] and I could not found any item that describe how can I test the adhesiion of the yellow chromate.
I have heard that I can use an eraser to find for any poor adhesion however I would like to have a solid ASTM to refer for.

Please help,

Jesus Armando Fernandez Mingura
- Nogales, Arizona, USA

ASTM B201-80 [link is to spec at TechStreet](2004) "Standard Practice for Testing Chromate Coatings on Zinc and Cadmium Surfaces" has an abrasion test using a soft gum eraser. B571-97 [link is to spec at TechStreet] tests adhesion of metallic coatings, e.g., the zinc plating.

If the chromated zinc gets painted (or if you're willing to paint test panels), try the paint adhesion tests in ASTM B449 [link is to spec at TechStreet] "Standard Specification for Chromates on Aluminum." These include the wet tape & knife tests of FED-STD-141 [link is to spec at TechStreet], plus a cross hatched-paint tape test.

Ken Vlach - Goleta, California