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Hardening aluminum for nikasil coating for high pressure

I am looking for a method to get the maximum hardness on aluminum (7075,2024,or cast) under Nikasil plating for high pressure loads without deformation. Maybe a coating or spray metal process? The problem is that in my application I cannot restrict the thermal expansion of the aluminum. Currently iron is sprayed on the aluminum .05 inches thick, ground smooth, and hard chromed. Unfortunately this reduces the aluminum's thermal expansion rate causing gaps in mating aluminum parts in my application.

George Reeder
Engine Development - Detroit, Michigan
2006

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Keronite may even help you eliminate the Nikasil as well.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

2006

It is not very clear what you want to accomplish. You say you want to increase aluminum hardness (there are hardening heat treatments for some Al alloys called precipitation or age hardening). Then you mention about thermal expansion and a coating of iron and chrome. Do you want to match iron and aluminum in their thermal expansion and hardness? To my knowledge this is impossible with present state of the science. You would have to select another material with the physical properties that better match your purpose.

Guillermo Marrufo
Monterrey, NL, Mexico
2006