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Hard Anodized Layer "Chipping"

We received a set of hard-anodized aluminum DIN 1725/3.4345 AlZnMgCu 0.5 (I believe AA mat. Designation 7022) dies on which the hard anodized layer easily chips of the substrate. The supplier advised that the problem is rare and caused by the zinc in the aluminum alloy and that the current bond/penetration of the hard-anodized layer is the best they can achieve. Our manufacturing process requires high abrasion resistance and we will have premature failure of these dies due to the insufficient bond of the hard-anodized layer.

Which alternative finishing process could be used to achieve high abrasion resistance on this Al substrate? (Note: Die dimensions are critical) Or is there a hard anodizing-process, which could work with the Zinc problem mentioned by the supplier?

M. Swoboda
REHAU Industries Inc. - Baie d'Urfe, Quebec, Canada
2001

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Try Hard Chrome Plating. This should adhere and work well on 7022Alloy.

Frank R Knox
- Lafayette, Indiana
2007