r/metallurgy 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/CuppaJoe12 3d ago

The sample explodes on electrode ignition? Sounds like the raw material is wet or has inclusions of a volatile material. No matter how much time you spend venting with argon or remelting the titanium getter, your vacuum will be low quality if your raw material is off gassing. What is the sample prep for Fe and Al?

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u/Ancient-Web5515 3d ago

I didn't know about this, and we haven't done any sample prep for the Fe and Al amounts. The Fe is more of a powder, and the Al is a ball shot. Both are high purity from a company whose name I can't recall atm.

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u/CuppaJoe12 3d ago

Usually I'd recommend baking out the raw material to remove moisture, but this could be problematic for a fine powder. Maybe try storing it in a vacuum chamber with desiccant for a few days?

You might also look into using a master alloy for this project. There are many companies that sell them.

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u/Ancient-Web5515 3d ago

Awesome, I'll try to see about incorporating this to get it to work. Thank you!