Aluminum oxidized corny blow off

[spittybug]

I can't remember where I bought these, but I got 2 or 3 to replace old plastic ones in some of my corny lids.

The first time I discovered one covered in white powder I thought I had an infection. When it happened a second time I realized it is oxidization. WTF??? As these sit in SS lids, is this galvanic corrosion of the 'lesser' metal? Any means to passivate them?

 

[day_trippr]

There are many situations where aluminum and stainless don't play nice together, and this clearly appears to be one of them.

For example, one can use stainless steel fasteners on an aluminum structure, but the reverse is never true.
I'd say that fitting vs keg would fit the latter case.

And the acidic beer would serve as an excellent electrolyte.
The rest is basic chemistry.
I don't think there's anything practical that could be done to keep that corrosion from happening...