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Zinc Oxide formation

  1. Sep 1, 2015 #1
    Hi
    I am aware that Zinc Oxide (ZnO) is in the form of white powder. Can I leave a strip of Zinc in a room (at presence of Oxygen) so that it becomes oxidised therefore the same thing is resulted but in form of a metal strip instead of powder? Would the resulted strip become as oxidised as the powder? How long do I have to leave it in a room full of Oxygen?

    Thanks
     
  2. jcsd
  3. Sep 1, 2015 #2

    Borek

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    During oxidation metallic zinc will become a white powder, that's chemistry for ya :wink:

    How long it will take is not easy to estimate. It won't be fast, zinc granules (often used in the lab) are stable enough that they can be kept just in a jar (that is regularly opened) for years.
     
  4. Sep 1, 2015 #3
    Thanks Borek
     
  5. Sep 1, 2015 #4
    Not 100% sure, but I can tell you that Zinc oxidises pretty quickly, faster than Iron. I don't think the whole strip will just completely break down very quickly, for the whole strip to become Zinc Oxide and form a salt, a lot of time may be needed. Zinc is used for galvanisation, because it oxidises really quickly, forming a protective Zinc Oxide layer.

    Try consult people who specialise in chemistry if you are not satisfied with the information you have received so far.
     
  6. Sep 1, 2015 #5

    Borek

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    This is actually a bit more complex. While you are right about it being covered with an oxide layer, it is used because it protects the iron below in a same way sacrificial anodes do - it corrodes first, leaving iron untouched.
     
  7. Sep 1, 2015 #6

    Nidum

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    Ingots of zinc metal as used in foundries are sometimes stored for long periods in poor conditions .

    One noticeable effect is that the ingots become slimy to feel - like a bar of soap . Can only guess why that would be . Also the very attractive crystalline patterns found on surfaces of new ingots tend to degrade and become less well defined over time .

    At higher temperatures in a melt of zinc metal or a high zinc alloy some zinc will boil off and form clouds of zinc oxide which thickly coat everything around with white powder if the correct melting process is not followed .
     
  8. Sep 2, 2015 #7
    The zinc oxide reacts with the CO2 in the air to form a protective layer of zinc carbonate, which with the Zinc oxide layer hinders further oxidation.
    That could be the slimy feel, but is responsible for the appearance of the degradation of the crystal structure.
    On an iron surface there is a two fold protection:
    1. barrier protection from further corrosion form the zinc oxide layer
    2. sacrificial galvanic protection
     
  9. Sep 2, 2015 #8
    I didn't feel the need to mention that, because it seemed pointless to go off-topic putting too much effort into describing the whole reason for Zn to be used in galvanisation. It also seemed pretty obvious. Thank you for your suggestion.
     
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