metal nitric no reaction

[steyr223]

how is everything
this should be a simple one

I have keypads from pin code entry pads
between the key pad and the pcb there is a sqaure piece of metal
thats springy as to make contact and then push the pad back up
one side is silver or aluminum color the other side is gold

I put 4 of them in diluted nitric 50/50 no reaction
it was cold 40 deg f

the next morning the metal is a tiny bit smaller but the gold came off in
full size no flakes at all

is the metal stainless or maybe aluminum

i can post pics if needed

by the way the solution is clear like water (the nitric/water)

thanks steyr223

 

[Geo]

low reactivity to nitric,springy, sounds like some form of stainless steel.

 

[steyr223]

thanks geo

 

[Harold_V]

You might consider testing the material to be certain. Aluminum will dissolve readily in HCl, and should not discolor the resulting solution much, depending on the type of alloy. By contrast, I expect that stainless would discolor the solution quickly----plus it's much heavier than aluminum. Color, too, is an indicator. Aluminum is very white in the scheme of things, almost as white as silver, while most stainless alloys, in particular the 300 series, which is non-magnetic, would have a distinct hint of yellow coloration. It's subtle, but placed next to aluminum, you'll see what I mean.

I recommend you do these tests, so you'll become familiar with the metals. Makes life a lot easier when you can identify what you're working with.

Harold