If one were to pass a large current across a piece of magnesium ribbon (think "short circuit across a magnesium fuse"), would it ignite before melting and breaking the circuit?
I think it would, due to magnesiums auto-ignition temperature of 883F, and melting point of 1202F.
Anyone tried this or seen it done?
I imagine it would depend on how quickly you ramped up. If you slowly ramped it up then yeah, I'd say it would ignite first but for a quick (ie: instantaneous) turn on, I imagine it would do both. Either way, I think it's igniting.
I've done a lot of thermal evaporation in my semiconductor research. I did a research project creating organic transistors and one of the steps involved putting powdered pentacene into a tungsten crucible and ramping up the current slowly, until the crucible was glowing orange. I don't remember the amperage offhand, it's in my notebook, which is with the PI for that project.
I haven't worked with Mg, though I imagine I could have some fun with it. :D