Galling resistant aluminium alloy grade ?

[Uralsk]

what kind of aluminium alloy grade is the most resistant to galling with nickel ?

 

[TugboatEng]

Aluminum and galling resistant are mutually exclusive terms.

There have been some novel ideas that involve dispersing galling resistant compounds into the aluminum. Here is one that uses nickel coated graphite:

https://www.jstor.org/stable/44564310

Or hypereutectic alloys with silicon:

https://www.jstor.org/stable/44650624

 

[EdStainless]

A Ni alloy or Ni200 (pure Ni)?
These are two of the more gall sensitive materials that there are.
My guess is that contact pressure over 2ksi will assure galling.
Use an insert to keep them from touching each other.

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P.E. Metallurgy, consulting work welcomed

 

[Uralsk]

i'm planning to use pure nickel

 

[EdStainless]

What temp? Dry or lubricated? Can you use washers/spacers/bushings?
One thought is to look at Electroless Ni plating on the Al, then age it to harden it.
But preventing contact is a better option.

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P.E. Metallurgy, consulting work welcomed

 

[WKTaylor]

Aluminum alloys and nickel are extremely dissimilar. Direct contact between bare parts, with even a whiff of electrolyte and oxygen, is guaranteed to initiate massive aluminum corrosion... overwhelming any expected galling problem.

Anodize with baked-on corrosion resistive solid film lubricant [fastener grade coating SFL] on the aluminum surface... AND flash-chrome plate on your polished [8-microinches RA] nickel part... might work OK... but test-test-test to validate in real-world environments.

This combination would probably allow relatively slow movement with relatively low contact pressure for moderate-to-good 'endurance'.



Regards, Wil Taylor
o Trust - But Verify!
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation, Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", HBA forum]
o Only fools and charlatans know everything and understand everything." -Anton Chekhov

 

[MC6]

Solid film lubricant as said, or DLC or some kind of plasma deposition. Nikasil for example...

The cost should steer you away pretty quickly.