An alloy is a material composed of two or more metals or a metal and a nonmetal. And, they are usually formed by heating the elements to their melting points, and then cooling them, so that the components mix. Now, why doesn't this works backwards i.e. if we heat the alloy again to melting point of their constituents, and they should separate?

  • $\begingroup$ It might have something to do with entropy... $\endgroup$ – tkhanna42 Jun 16 '15 at 14:24
  • $\begingroup$ If the liquids are immiscible, they will separate. But entropy (as @tennispro1213 points out) and enthalpies of mixing (in the solid and/or liquid phases) have to be dealt with. $\endgroup$ – Jon Custer Jun 16 '15 at 14:28

Once the alloy has been formed the atoms from the different metals will have shared there electrons with each other and come to an equilibrium. In this state the metal atoms have formed a complex structure which has a different reactivity or properties than each individual metal did in its original form .

  • $\begingroup$ Things have surely been compounded together but I'm not sure if an alloy is ever referred to as a compound. It's not an organic compound I know that. $\endgroup$ – Technetium Jun 16 '15 at 7:31

If you melt the alloy and then use electrolysis, or if you use a redox reaction, you should be able to separate the components.

For example, if you used a basic acid, let's say hydrochloric acid, on a zinc-copper alloy, I'd imagine the zinc would be removed from the alloy and taking the hydrogen's place, forming zinc chloride, leaving hydrogen gas and copper metal.

This is based off of simple redox reaction memories and no personal experience. However, if you're curious, try it out!

  • $\begingroup$ But, I am sure that they are not resolvable ! $\endgroup$ – anshabhi Jun 16 '15 at 7:26
  • $\begingroup$ I'm not entirely sure what you mean. $\endgroup$ – Dylan Spano Jun 16 '15 at 7:26
  • $\begingroup$ I mean that "you should be able to separate the components" is not true. $\endgroup$ – anshabhi Jun 16 '15 at 7:27
  • $\begingroup$ Now that I think about it, maybe not. Adding chromium to steel allows it to not rust, so I guess the reactions change. Electrolysis definitely sounds like it would work, though. $\endgroup$ – Dylan Spano Jun 16 '15 at 7:28
  • $\begingroup$ I think it means how come the original metals can't be recovered from the alloy just by heating the alloy to the melting point temp respective to metals in their original state. $\endgroup$ – Technetium Jun 16 '15 at 7:36

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