Different thermites

[rthmjohn]

The only thermite I knew of until recently was the ferroaluminum thermite. I now know that any oxide can be used (as is stated in the definition of thermite). Does this mean that V205 or MnO2 can be used in thermites? What are some other strange thermites that you've heard of?

[Aspirin]

CuO/Al is another nice thermite

 

and all these oxides can be used with aluminium:

Fe3O4, Co3O4, CoO, NiO, MnO2, Mn2O3, Mn3O4, CrO3, MoO3, MoO2, V2O5, SnO2, CuO and Cu2O

[rthmjohn]

Sweet. btw... I've almost exhausted my supply of Al powder, and unitednuclear has discontinued its sale. Where do you guys get yours?

[Aspirin]

http://www.skylighter.com is another source for Al powder

[latentheat]

Have a look at the activity series of metals, or the standard reduction potentials table. A metal with a more negative reduction potential can reduce a metal with a more positive reduction potential from its oxide.

 

For example, ferro aluminum thermite works because the reduction potential of Al³⁺ is -1.66 volts while the reduction potential of Fe³⁺ is -0.04 volts.

 

Al wants to give up its electrons more badly than Fe, and we know this because it takes more energy to reduce Al from an oxidized state.

 

Here's a good table of reduction potentials...

http://en.wikipedia.org/wiki/Table_of_standard_electrode_potentials

 

This table is very useful for predicting thermites and other types of single displacement reactions.

[rthmjohn]

Thanks latentheat. Aspirin, do you know if skylighter discloses personal info?

[weldermanx]

hey you know etcha sketches? well the powder in them is very pure aluminum and it will serve its uses for thermite just fine

[ThermiteMan]

That was very messy......verryyyy messy. its so fine your hands get covered in it.

[Silencer]

Doesn't the etcha sketch work with magnets? Aluminum isn't magnetic...

[rthmjohn]

I was thinking maybe I could use Al electrodes (I'm guessing they should be pretty pure since their from a supply co.) and file them down with a bastard file and then place the filings in a ball mill...

[ThermiteMan]

EtchaSketches workwiht a pointer mechanism that is operated with pullies from the dials.when you turn the thing upside down, the aluminum covered plastic beads coat the plexiglass again.

[6E30306200]

Sulfates can also be used.

 

 

These three thermites have a calculated temperature of over 5000 Kelvin

Y + MnO2

Nd + PbO2

Nd + I2O5

 

Remember to protect your eyes against the ultraviolet radiation that is created from thermites.

[weldermanx]

the etchasketch i used was perfect the was not plastic in the powder it works perfectly for thermite

[jowrose]

skylighter is ok, but i find that they're a bit on the expensive side. I got some great quality aluminum powder on ebay, 5 pounds for 25 bucks. Works perfectly in the thermite reaction with Fe2O3, never had to relight any of it. I'm going to get my hands on some magnetite soon though, I'll see how that works out. I've heard that it's safer (less splatter) and even that it burns hotter. I'll have to see for myself. Does anyone know if the ratio between aluminum and iron oxide is different for a magnetite reaction? or is it still 1 to 3?

[jowrose]

Just got back from the beach, collected about 2 pounds of impure magnetite. I plan on running my magnets over the magnetite/sand mixture several times to purify it; i have seen pictures of what the pure stuff should look like (it's also the stuff used in etch-a-sketches, i think). I'll post again once the purification is complete, then it's on to the thermite testing...