Pyro
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lithium oxidation
Hello,
I just watched this: http://www.youtube.com/watch?v=RA5dMJKxwVI
start watching at 17', how do they stop that lithium from oxidizing? I thought of an inert atmosphere, but those guys are there.
any ideas?
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confused
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No idea, it could be that they use some thin film of oil to protect it...my lithium always seems to tarnish in contact with air
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quest
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I guess they take out all the moisture from the air, not so hard.
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BromicAcid
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Even if the moisture was out of the air you would still expect oxidation. Very interesting that they would do everything so open like that. And the
metal looks very nice too, at first I thought they would use a thin layer of oil but it doesn't seem that way. I guess since it's automated
everything moves fast and continuously. With the moisture out of the air maybe attack is minimized. For the step where they are putting the poly
coating on the lithium it seems as if that machine is inside a chamber but other than that the workers seem to have full interaction with the big
chunk of lithium. You'd think that would be a fire hazard.
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elementcollector1
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It's not just moisture, CO2, N2 and O2 all react with Li to form the respective compounds. I remember Zan Divine saying that moisture was almost a
catalyst for the reaction, but I don't think it's necessary. Oil painted onto the surface is the most likely explanation.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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12AX7
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Would they be able to lubricate at all? A battery's got to be pretty squeaky before it's assembled. Could be it's cleaned off in an automated glove
box by then. A lot of steps are omitted to fit the segment into the allotted time, so it's hard to say. It makes sense that the billet and extrusion
are done in fairly benign conditions but the rolled foil seems to have more cover (though still likely in air).
Anyone know offhand the reaction rate with O2, CO2 and N2? I wouldn't think N2 would go at room temperature, but O2 does with all kinds of things.
Tim
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AndersHoveland
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It probably would. Even though N2 will not react with elemental sodium or potassium at any temperature, it will gradually react with metallic
calcium at room temperature, apparently:
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At normal temperature, Ca rapidly acquires a layer of nitride and oxide, but forming chiefly nitride. At higher temperature both CaO and Ca3N2 are
formed.
"Concise Encyclopedia Chemistry", deGruyter
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Someone left some calcium in my glovebox in an open container. The glovebox was obviously 100% nitrogen environment. The box also happened to be at
~30 C at the time. By the next day it was all calcium nitride.
"enahs" from "Chemical Forums"
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Interestingly, metallic calcium does not actually react with anhydrous ammonia at room temperature, but rather dissolves in the cold liquid. When
heated (or with the use of an iron nitrate catalyst) it forms calcium nitride and calcium hydride, which are very different products from the
reaction of sodium and NH3.
6 Ca + 2 NH3 --> Ca3N2 + 3 CaH2
2 Na + 2 NH3 --> 2 NaNH2 + H2
Nitrogen is actually soluble (only slightly) in molten sodium. "N-Na (Nitrogen-Sodium) System", James Sangster, Journal of Phase
Equilibria and Diffusion
Volume 25, Number 6, 560-563,
[Edited on 15-4-2013 by AndersHoveland]
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AJKOER
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OK, what about forming an alloy?
Logic, for example, common brass is 63% copper and 37% zinc, but it certainly doesn't tarnish like copper.
The answer is apparently yes, see "NEW ALUMINUM LITHIUM ALLOYS FOR AEROSPACE APPLICATIONS" ( http://www.google.com/url?sa=t&rct=j&q=lithium%20all... ) to quote:
"Recent alloy developments have produced a new
generation of Al-Li alloys which provide not
only density weight savings, but also many
property benefits such as excellent corrosion
resistance, good spectrum fatigue crack growth
performance, a good strength and toughness
combination and compatibility with standard
manufacturing techniques. This results in wellbalanced,
light weight aluminum alloys"
[Edited on 31-5-2013 by AJKOER]
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violet sin
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those alloys 2099 and 2199 from the link are only 1.6-2% and 1.4-1.8% Li respectively. there is more copper 2.4-3% and 2.3-2.9% res. so I'm not sure
it really applies here. but still a good read.
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