Titanium anhydrous ammonia explosions

Stress-corrosion-cracking failures in early titanium rocket-program applications. Titanium + anhydrous NH3 (less than ~100 ppm moisture) → titanium nitride and titanium hydride; loss of protective oxide → "exciting explosions" on launch pads.

So you can talk about thermodynamic nobility and practical nobility, and practical nobility is what really counts. But the problem with practical nobility: if you lose your protective oxide skin on some of these things that are the best, like titanium — I told you, you can dissolve titanium's own oxide at 900 C. The other thing, early on, they had some very serious explosions where titanium was being used when they first developed it, because it had such good corrosion resistance, and they had a problem with anhydrous ammonia. Anhydrous ammonia, NH3 — if it has no moisture in it, like less than a hundred parts per million of moisture, the titanium will react. Titanium plus NH3 reacts to form titanium nitride, which is very stable, plus titanium hydride, which is very stable. There are some x's and y's and z's in there to balance the equation. Titanium will react with anhydrous ammonia and cause stress corrosion cracking, and they had some really exciting explosions. They were using some of this with the rocket programs early on and blew up some of the launch pads.

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