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Fading of black hard anodising part at high temperature

I am using a black hard anodising aluminum part at a temperature of around 300 °C. Very soon, the black color faded. I think it was due to the decomposition of the dye at high temperature. Is there any dye or way so that I can keep the black color in my application?

Thanks,

Bonnie Chow
- Macau
2003

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1) All dyed anodic coatings must be sealed to lock in the dye stuff. In general, hardcoat anodize is left unsealed to render the best abrasion resistance. I'd guess your part was left unsealed which permits the dye to fade fast. Sealing would have prevented this.

2) Dyes are rated for both light and heat fastness; your provider may have used a dye with poor heat fastness. 300 °C is not that hot; we routinely test our black anodize at 600 °F for the medical and electronics industry. It can be done by a quality conscious shop!

Anodically speaking, good luck.

Milt Stevenson, Jr.
Plating shop technical manager - Syracuse, New York
2003

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