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Author Topic: Oxidation query  (Read 7287 times)

Offline Xule

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Oxidation query
« on: 25/01/2006 18:09:49 »
Does any metal turn black in presence of O2? Please answer, there's money riding on this.

"Never tell the same lie twice."


 

Offline Steve Vai

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Re: Oxidation query
« Reply #1 on: 25/01/2006 19:24:41 »
No, copper is the main one i can think of that actually turns black, but many other transition metal oxides are colourful and are generally the oxides used to make glazes on pottery and other colourful things.

A quick example which disproves your idea, take a look at rust, its an iron oxide, and as far as im aware its not black, unless i kinda missed somethign important :D

"Turkeys killed my family" - Chip, 02/09/2005, 12:49
 

another_someone

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Re: Oxidation query
« Reply #2 on: 25/01/2006 19:51:55 »
How about silver?
 

Offline Xule

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Re: Oxidation query
« Reply #3 on: 26/01/2006 17:13:12 »
quote:
Originally posted by Steve Vai

No, copper is the main one i can think of that actually turns black, but many other transition metal oxides are colourful and are generally the oxides used to make glazes on pottery and other colourful things.

A quick example which disproves your idea, take a look at rust, its an iron oxide, and as far as im aware its not black, unless i kinda missed somethign important :D

"Turkeys killed my family" - Chip, 02/09/2005, 12:49



 Copper turns green in the presence of O2, doesn't it? That's why the Statue of Liberty is green.
 There has to be one metal that turns black, i'm sure i've heard of it before.

"Never tell the same lie twice."
 

another_someone

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Re: Oxidation query
« Reply #4 on: 26/01/2006 18:46:21 »
quote:
Originally posted by Xule

 Copper turns green in the presence of O2, doesn't it? That's why the Statue of Liberty is green.
 There has to be one metal that turns black, i'm sure i've heard of it before.




I think I mentioned that I believe Silver Oxide may be black
 

sharkeyandgeorge

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Re: Oxidation query
« Reply #5 on: 27/01/2006 11:39:19 »
yeah another someones right silver does oxidise balack but it may have some thing to do with the purity

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ROBERT

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Re: Oxidation query
« Reply #6 on: 27/01/2006 14:17:18 »
I think the "black" in black & white photographs is Silver.
« Last Edit: 27/01/2006 14:19:25 by ROBERT »
 

Offline Xule

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Re: Oxidation query
« Reply #7 on: 27/01/2006 17:37:13 »
quote:
Originally posted by another_someone

quote:
Originally posted by Xule

 Copper turns green in the presence of O2, doesn't it? That's why the Statue of Liberty is green.
 There has to be one metal that turns black, i'm sure i've heard of it before.




I think I mentioned that I believe Silver Oxide may be black



 Oh, sorry, i didn't notice your post. Thank you.

"Never tell the same lie twice."
 

ROBERT

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Re: Oxidation query
« Reply #8 on: 30/01/2006 13:08:25 »
""Iron has another oxide, Fe3O4, which is sometimes called black oxide, black rust, or hammerscale. Black oxide is a good protection for steel. Like aluminum oxide, black oxide molecules are the same size as iron molecules, so black oxide does not grow or flake. Black oxide is true gun bluing and the oxide found on some drill bits. Black oxide is also seen on iron and steel that has been hot-worked.""
http://www.metalwebnews.com/howto/rust/rust.html
 

Offline cuso4

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Re: Oxidation query
« Reply #9 on: 22/02/2006 18:21:34 »
quote:
Originally posted by ROBERT

I think the "black" in black & white photographs is Silver.



The substance used in photography is a silver(I) halide complex. The halide X- can be oxidised to X by shining light on it and releases an electron. This electron reduces Ag+ to silver metal (black).

But silver metal itself is quite stable and not easily oxidised by O2 in air.


Angel
 

Offline cuso4

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Re: Oxidation query
« Reply #10 on: 22/02/2006 18:24:40 »
I think MnO2 Manganese(II) oxide is black and I think this is the product you get if you heat Mn in air.

Angel
 

Offline Vadermort

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Re: Oxidation query
« Reply #11 on: 26/02/2006 12:06:07 »
Yeah you r right Manganese dioxide is black. it is used in dry cell bateries.

b.s
 

Offline DrDick

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Re: Oxidation query
« Reply #12 on: 04/04/2006 20:03:55 »
quote:
Originally posted by Xule

quote:
Originally posted by Steve Vai

No, copper is the main one i can think of that actually turns black, but many other transition metal oxides are colourful and are generally the oxides used to make glazes on pottery and other colourful things.

A quick example which disproves your idea, take a look at rust, its an iron oxide, and as far as im aware its not black, unless i kinda missed somethign important :D

"Turkeys killed my family" - Chip, 02/09/2005, 12:49



 Copper turns green in the presence of O2, doesn't it? That's why the Statue of Liberty is green.
 There has to be one metal that turns black, i'm sure i've heard of it before.

"Never tell the same lie twice."



The green you see on the Statue of Liberty is a rather complex result of copper interacting with acid rain (essentially very dilute H2SO4) to form a mixture of CuSO4 and Cu(OH)2.
The darker green on the torch is a more soluble compound, which is a mixture of CuCl2 and Cu(OH)2 (the Cl presumably coming from sea-spray corrosion).
See also http://www.highbeam.com/library/docfree.asp?DOCID=1G1:4610599&ctrlInfo=Round19%3AMode19b%3ADocG%3AResult&ao=

DrDick
 

Offline kbalani

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Re: Oxidation query
« Reply #13 on: 21/04/2006 21:20:46 »
Can anyone please tell me the wettability of aluminum oxide (Al2O3) on graphite (or carbon) alongwith its reference.
thanks
Kantesh
 

Offline Hadrian

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Re: Oxidation query
« Reply #14 on: 21/04/2006 22:57:51 »
go to and search for silver.

http://www.epi.com/metalantiquing/box-pages.html#313

i think they should have a product that will do waht you want.


:)

What you do speaks so loudly that I cannot hear what you say.
 

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Re: Oxidation query
« Reply #14 on: 21/04/2006 22:57:51 »

 

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