[amorphous]

Yep. Some time back, researchers were experimenting with a reaction device which used pure aluminum - no oxide coating - and mixing it with plain water for a source of hydrogen gas for fuel-cell vehicles. Not sure what the outcome was, but probably a little on the dangerous side.

I used a mixture with sulfur in my amateur rocketry days.

[yarddog]

The mention of amateur rocketry reminds me of something funny about 45 years ago.

I visited a small telephone company in South Alabama. The secretary told me the president and another two employees were out in the office park setting off a rocket.

I stepped outside just in time to see them set it off. The rocket made it about 10 feet and then turned toward another building. All three of them took off running.

It didn’t engender a whole lot of confidence in Graceba Telephone Company.

[Steely Tom]

When I was at GE once upon a time, a team on another floor was working on sodium-sulfur batteries. These contained molten sulfur and molten sodium in a long steel pipe; the two reactants were kept separated by an alumina tube that was really a very deep cup. If the alumina cup cracked, it was a good idea to be elsewhere. I forgot to mention that the whole thing had to be at about 400 degrees C in order to work.

One day the cup cracked on a fully charged battery. The ensuing high-speed chemical reaction caused a blast of flame to shoot out of the end of the tube, whereupon it cut through the (steel) lab wall and flared out into the hallway.

Shortly after this, the battery group was moved to Malta, NY, where there were concrete bunkers left over from WWII.