Metco 450/NiGr on Aluminum?

[brian_dev]

I am struggling to figure out whether or not metco 450 bond coat / 75/25 NiGr is a good idea on the ID of a 3" aluminum bore (grade C355).

The part will operate at 325F with excursions over 400F.

Does anyone have experience with mismatched coefficients of expansion? We had a test part failure at the substrate / bond coat interface and are debating whether it debonded due to mechanical stress or never bonded due to an unknown spray or prep issue.

Any suggestions for a bond coat / abradeable top coating on aluminum at sporty temperatures?

Is Metco 480 a safer bet than 450?

Thanks in advance! This board is a fantastic resource.

[kschewe]

450 or 480 is fine on aluminum at that temp. Many oems use that. Sometimes i also use moly on aluminum as a bond coat. Don't preheat the aluminum and make sure its gritblasted with coarse grit. Don't overheat the substrate, 300F max

[Vijay Deshpande]

AL Bronze is the best bond coat for Aluminium substrates.