What is the preferred evaporation technique to evaporate Niobium usually?
My tungsten boat broke during evaporation and chamber vacuum fell by 2 orders though I could get some material.
What method do you use to evaporate material with melting point of ~3000 K using a boat?.. :-)
I guess Nb could be evaporated by some sort of laser (plasma) technique...
No doubt, W with much higher mt(3420C) looks to be most suit able,but it has ONE LIMITATION . It ATTACKS Nb near ITS MPT(2468C).The use of Mo(mp-2893C) or Ta( mpt 2896C) boats is recommended as Nb attacks NEITHER Mo nor Ta though their mps are lower than W YET sufficiently higher than Nb(2468C).
Since Nb attacks W, I believe the best way is to use e-beam assisted source.
I also doubt how you can ramp the temperature so high for any crucible or system. To my knowledge, the vapour pressure (torr) of Nb is 10E-8 at 1728C, 10E-6 at 1977C.
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