Sciencemadness Discussion Board

Metal-metal solvation

platedish29 - 14-10-2012 at 15:00

Hello everybuddy!
Recently I bought some Mg scrap parts and pretend to cast a sparking stone out of it. As one should know, magnesium alone is quite safe to handle and won't ignite on fire. A manufacter described his firestarter block as contaning rare earth metals, Cu, Zn and Fe.
Maybe the so said rare earth are simply some mischmetal dissolved in molten Mg?
So the question is, does alloying metals dissolve in one another in the same fashion salt dissolves in water, i.e. dissolution starts at different phase mixture?
Because My blowtorch is a simple propane-air torch which at best effortfully metlz copper.
Mg melting point is just 650°C...

elementcollector1 - 14-10-2012 at 15:37

Nope. The block itself is 95% Mg, while the striker is the mixture of RE's, Fe, etc.

violet sin - 14-10-2012 at 16:19

thats what I thought also, mg block and separate striker, but some of the more recent strikers are just a thick rod that carves much more easily than standard ferrocerium 'flints'. got one in a test sample from a hunting club and is also much more silver magnesium looking. the manufacturer said that it was a magnesium fire starter. I think mayhaps platedish29 is right. this one is different but same idea.

http://www.campingsurvival.com/aufistflstan.html

"...has magnesium built in..."

12AX7 - 14-10-2012 at 17:21

Magnesium alone doesn't alloy with iron (indeed, molten magnesium is usually handled in iron ladles and crucibles), but it does with rare earths (cerium, lanthanum, etc.), reacting to form intermetallic compounds. Iron reacts similarly with rare earths. Probably, an even mixture of all three results in a weak, brittle mixture of intermetallics without immiscible phases.

So, as far as mixing mischmetal with magnesium, it at least seems possible. Ought to spark hotter?

Tim

elementcollector1 - 14-10-2012 at 18:11

I don't really see *why* they'd alloy magnesium with the RE's, as those are the principal component of the mischmetal that allows it to spark so readily. But who knows?

platedish29 - 16-10-2012 at 16:01

Quote: Originally posted by elementcollector1  
I don't really see *why* they'd alloy magnesium with the RE's, as those are the principal component of the mischmetal that allows it to spark so readily. But who knows?


And isn't it logicall at all? For sure the purposes are on making cursed structural parts as at one touches with a cigarete or match or even the most innocent spark, to cause a tremendous runaway metallic fire, melting everything at a temperature ranging around 2500°C.

:o:o:o

*JK.*

Unofortunately guess there will be necessary some of those iron crucibles 12AX7 has mentioned about and apply coal fire around it.

UnintentionalChaos - 16-10-2012 at 16:13

The "softer" striker rods contain far less of the hardeners in traditional ferrocerium "flints." They contain less alloying elements (iron) are are closer to pure mischmetal. I have a few of these rods (for fire starting purposes)

If you've ever desired to beat someone to death with a chunk of rare earths, I reccomend this: http://goinggear.com/survival/fire/firesteel-ferro-rod-blank...

platedish29 - 16-10-2012 at 22:40

Quote: Originally posted by UnintentionalChaos  
The "softer" striker rods contain far less of the hardeners in traditional ferrocerium "flints." They contain less alloying elements (iron) are are closer to pure mischmetal. I have a few of these rods (for fire starting purposes)

If you've ever desired to beat someone to death with a chunk of rare earths, I reccomend this: http://goinggear.com/survival/fire/firesteel-ferro-rod-blank...


Proceding with the experimentals is a next-month plan. But theres no reason to hide our opinions yet!
Yes the hardener is said to be iron oxide, I don't think pure iron would remain that hard with all the soft RE in the of flint.
Thus on dissolving Fe2O3 would sink in molten magnesium (which is a progress since worries about surface tension and oxide layer completely halting the solvation process are now eliminated).
Btw, I'm about to receive a hundred flint stone this month the remaining problem being to to buy charcoal.
My crucible is in fact a medical grade stainless steel cup.

I hope shit does not immediately go bad, as for the molten magnesium burning non stop because mischmetal added on.
:(

kristofvagyok - 17-10-2012 at 14:56

Quote: Originally posted by platedish29  
I hope shit does not immediately go bad, as for the molten magnesium burning non stop because mischmetal added on.
:(

Melting magnesium in a steel crucible with a propane torch doesn't look as idea for a long life... If you won't do this under argon or anything what will protect the Mg from air it will ignite or it will oxidize.

Long ago I have made a few samples of wood's alloy for demonstration. The Cd, Sn, Pb and Bi was melted in a steel eradicable under some paraffin wax. On the bunsen the paraffin melted and ignited, but it prevented the alloy from the oxidation. When the sensitivity was demonstrated, then the paraffin was removed and I have melted it on the air. It oxidized in no time. And it wasn't 650 Celsius hot....

So think this project again, melting Mg could turn out to be a really bad joke.

12AX7 - 17-10-2012 at 16:02

Mg is usually melted under inert cover: molten salts (which double as a flux), N2 (cheap), Ar (why bother when N2 will work?!) or, surprisingly, SO2 (often sourced from a hunk of elemental sulfur tossed on the melt). I might be forgetting something, but I know CO2 works about as well as air, so that ain't it.

Most Mg alloys are rich with aluminum which also helps things. I've made magnalium (50% MgAl) in air with no flux or cover before. If you get it slightly too hot, it does start corroding into a black rumpled brainy mess.

Tim

[Edited on 10-18-2012 by 12AX7]

platedish29 - 17-10-2012 at 18:49

Holy #$%
The most recent density measure picked up showed a density of 2,74g/cm³ for the "magnesium" I had bought a local car junkyard, with 1g dev. on weight and 2mL dev. on volume, as calculated from 74g divided by 27mL.

This is so fuckin hilarious. Guess I'll have to bring my balance and graduated cilinder to the guy and so we can talk.

Do you guys think there is any test for at least 50% magnesium? To say, something that works with magnesium only.

[Edited on 18-10-2012 by platedish29]