Color fade Issue with anodized aluminum

[pro_robo]

I have anodized aluminium products in a very specific shade of color. It is hard anodized. Our usual customer base is in the Dry region, for the first time we shipped it to the West coast of USA. Within the first few weeks, we started noticing patches of faded colour on the product.

I would like to know what might be the reasons for the defect to appear, our anodizing vendor doesn't seem to have a clue on why its happening.

Thank you, appreciate your time.



I hope those white patches are visible, sorry couldnt get a better quality image.

 

[SWComposites]

Where exactly on West Coast? desert dry area? wet, humid area? right on the ocean (salt fog zone)?

 

[ctopher]

Maybe an issue with the material type, or not cleaned properly before anodize?

 

[3DDave]

Dyes are less stable molecules. Black dye tends to fade or turn other shades as the components decompose at different rates.

Hard anodize has less porosity so it retains less dye than typical anodize.

Was it sealed properly? This is key, post-dye, to cause the pores to be closed.

 

[Compositepro]

"Fading" is a conclusion that has not yet been established. The observed splotches could also be due to corrosion leaving white deposits. This should be observable under a microscope. Does it appear silvery or white?

 

[EdStainless]

Is there a sealer or topcoat on the dye?
For tougher environments you may need one.