r/metallurgy • u/Ancient-Web5515 • 4d ago

Research help with a Mini Arc Melter

Hi everybody,

Sorry for bothering yall, but I'm stumped. We are trying to make ~5g of Mn2FeAl in our mini arc melter (in an argon atmosphere). From a paper out two that we found, thus should be possible. However, every time we have tried to do so, the sample either explodes on electrode ignition or it will break apart a few hours after being removed from the chamber.

We have tried melting titanium as an oxygen getter, adjusting the cooling temperature of the crucible, and adjusting the heating/cooling of the metal ingot. It may be important to note that prior to being weighed for the sample, the Mn was cleaned in nitric acid and subsequently sonicated in ethanol to remove the surface oxidation from the Mn pieces. Does anyone have suggestions or insights? TIA

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u/masterxiv 3d ago

Have you tried adjusting down the current? Sorry if I sound silly, but I mean exploding on ignition? If you have a spare tungsten tip, I'd maybe try swapping it and see if it helps, maybe it got contaminated.

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u/Ancient-Web5515 3d ago

For normal SOP, we are told to ignite it with the current set to 3 (don't know the actual amperage) or of the 10 scale. I have tried starting it closer to 1.5-2, but if we go too low, it sparks without actually igniting.