Warning: Thermite is an extremely hot incendiary. Fire safety protocols must be in place.
Greetings fellow nerds.
The most common and best thermite is the famous iron oxide and aluminum thermite.
Most videos featuring thermite use this type and we ourselves have made it before.
But there is another type of thermite which substitutes chromium oxide for the iron oxide.
The result is a thermite that generates chromium metal rather iron.
To make it, we start with 56g of chromium (III) oxide.
It has this nice green color and is actually used as pigment.
Now the stoichiometric ratio with aluminum is 14 to 5, or 2.8 to 1.
So for 56g of chromium (III) oxide we add 20 g of aluminum powder.
Shake it up to thoroughly mix it and we can then go outside to test it.
As usual i'm going to light this with sparklers wrapped in some magnesium ribbon
which was very reliable for lighting iron based thermite.
Let me add the thermite.
Okay that's a little bit sloppy but oh well.
Now we light it up.
And it's...
...well shit.
Looks like the magnesium wrapped sparklers weren't hot enough to ignite it.
I'm going to have to try something a bit stronger.
Okay i've removed the wasted sparkler and now i'm going to add 8g of iron based thermite on top.
Since the iron based thermite is quite hot in of itself i'm hoping it will be able to ignite the chromium thermite.
And there we go.
Looks like it's working this time.
The reaction is much slower and more tame than the iron based thermite.
What's happening is the chromium oxide is reacting with the aluminum to form chromium and aluminum oxide.
This is very similar to the iron thermite reaction where we use iron oxide instead.
Looks like the reaction stopped before going through all the chromium thermite.
I'm going to try again but this time i'm going to pack the thermite into this iron can.
By packing the particles closer together, the heat should transfer better and ignite the neighboring particles more reliably.
And here we are.
I've put the iron thermite in a small ball of aluminum foil to better contain it.
Now let's ignite it.
NOW it's going.
Interestingly, it's not melting through the iron can, nor is the chromium itself melting.
There are two reasons for this.
First, chromium has a somewhat higher melting point than iron.
Second, the enthalpy of formation for chromium oxide is higher than the enthalpy of formation for iron oxide.
Thus when we essentially reverse the formation, we need more heat energy to do so.
This means there is less heat energy left over to melt the metal.
So for chromium thermite, we don't get the molten metal flows like we get for iron thermite.
So it's done.
I tried breaking this up but the slag and the chromium particles were too well mixed to separate.
This does not seem to be a viable way to get nuggets of chromium metal.
Ah well there you have it. Chromium thermite.
Thanks for watching.
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