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I want to melt some tungsten powder and cool it into small solid pieces of tungsten (around 10-50g). Because of tungsten's high melting point, it's hard to find things to hold it in. I had the idea of using levitation melting.

I found a paper on levitation melting tungsten. The authors used an electron beam in addition to an induction heater to melt the tungsten and melted it in a vacuum. I want to supply all the heat with an induction heater.

With this calculator, I calculated that a 25g tungsten sphere (5.3cm²) would emit 2.13kW of blackbody radiation at its melting point, assuming an emissivity of 0.38. I took the emissivity value from this paper.

I have a few questions:

  • Is this a viable way to melt tungsten?
  • Induction heaters have a kW rating. How much of that energy is used to heat the tungsten? How powerful of an induction heater do I need to offset the losses from blackbody radiation?
  • Do I need to use a vacuum chamber or inert atmosphere to prevent oxidation? What gases won't react with the tungsten?
LostXOR
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  • I think if you want to test the viability then you might as well just do it with iron first. A lot easier and a lot cheaper. If it works for iron it greatly increases the chance it will work for tungsten. The primary issue remaining being that tungsten is much less magnetic. I would think the most difficult issue is that induction heating itself messes with the magnetic field that is suppose to hold the metal captive. – DKNguyen Feb 02 '23 at 20:04
  • @jsotola I meant melt and then cool into a solid, I'll clarify that. – LostXOR Feb 02 '23 at 20:25
  • @DKNguyen To test it with iron I still need an induction heater, which is the most expensive part. I don't think tungsten not being magnetic will be a problem, since the levitation melting works with aluminum which isn't magnetic. – LostXOR Feb 02 '23 at 20:31
  • It seems the aluminum floats because it is turned into an electromagnet itself. So I guess it's not that lack of being magnetic that matters but the tungsten is much less conductive than aluminum so that would be the difficulty. But tungsten appears higher conductivity than steel so if it works for steel then shouldn't be an issue. But that's my opinion as someone who hasn't heard of levitation melting until today. – DKNguyen Feb 02 '23 at 21:32
  • Assuming your vacuum is held by a clean metal container, a lot of that black body radiation will be reflected back. – Drew Feb 10 '23 at 18:07

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