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Black anodized aluminum becomes white and chalky, any alternatives?

Hi,

I work for a company that makes parts for the marine industry. We black anodize some parts of our product. The parts anodized is 6061-T6 aluminum. Sometimes the product is exposed to water with gas and oil in it and the black bleaches and becomes a white and chalky within a year. Is there a different finish to use that will negate this problem? We already tried powder coating, but don't like it because it chips. Anodizing is what we have always done and we are not very knowledgable about other processes. Please offer any suggestions.

Thanks very much,

Phil Cone
- Honeybrook, Pennsylvania USA
2000

Try 2-step black anodizing. It holds the dye much longer, and will stand up to elements, such as the newer autoclaving solutions. best of luck.

Pete Faxon
- Oxnard, California
2000