Gallium can make aluminum soft and brittle as long as it bypasses the aluminum oxide normally formed on the surface of the aluminum (for example by scratching the surface).

Mercury can weaken aluminum as well.

Are there any other metals or alloys that can be "weakened" by coming in contact with gallium, mercury or any other substance?

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    $\begingroup$ Any? Better ask about ones then don't... $\endgroup$ – Mithoron Sep 15 '19 at 19:27
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    $\begingroup$ Amalgam#Liste_amalgam-bildender_Elemente Basically only Cr, Mo, W, and Mn, Fe, Co are safe. $\endgroup$ – Karl Sep 15 '19 at 20:21
  • $\begingroup$ Just found the term. It's called embrittlement. It can occur even on steel (hydrogen embrittlement). Hopefully someone will post a comprehensive answer, otherwise i'll post one. $\endgroup$ – user Sep 16 '19 at 6:38
  • $\begingroup$ I want to add that you probably refer to simple contact. Otherwise there should be plenty of alloys and metallic solids that suffer of embrittlement. Some are well known and still useful. $\endgroup$ – Alchimista Sep 16 '19 at 8:28
  • $\begingroup$ @Alchimista You are right, I'll edit the question to highlight it. $\endgroup$ – user Sep 16 '19 at 9:38

Gallium and Mercury, the latter in particular are absolute pests and poisons to most metals. There are too many to mention that will suffer the same consequences. I will mention the few that don't. Iron, Platinum, Tungsten and Tantalum all tolerate them fairly well. There are certainly more examples, but the common rule is; most don't.


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