ChemistryGhost - 15-3-2018 at 13:39
Will gallium metal wet glass in an inert atmosphere of nitrogen, argon, or neon?
I think it's the gallium oxide that wets the glass, not the gallium itself.
Gallium metal won't oxidize in an inert atmosphere, so I think it might not wet glass.
Same goes for the galinstan alloy.
I'm not sure though.
Reboot - 15-3-2018 at 17:30
Interesting thought. My assumption would be that gallium doesn't have much affinity for gallium oxide...but then, I'm not sure why gallium has an
affinity for silicon oxide (glass) either. :-)
My first thought was to toss some granules in a flask, suck out the air, then heat it liquify the gallium (or even do the same with a nitrogen flush
instead of vacuum)...but that wouldn't really address the question of whether pre-existing oxides or impurities within the gallium were involved in
the wetting phenomenon.
Hopefully somebody else will have ideas on either purifying/reducing the gallium to make it a valid test or explaining what might be driving the
phenomenon.
Melgar - 15-3-2018 at 21:15
Yeah, it will. They have to use a special coating on the inside of galinstan thermometers for that reason. The best way to keep gallium from wetting
glass is to put some other liquid in the bottle with it. Lots of different liquids work. Dilute sodium or potassium hydroxide solution seems to work
well. It will dissolve gallium oxide, but gallium won't oxidize just from water like aluminum will, and needs oxygen from the air to form its oxide.
So if you keep the bottle closed, the KOH or whatever will dissolve the oxide layer off and stop there.