For investigations of EBSD patterns I need tellurium crystals. Unfortunately, the only material I could get is tellurium powder. Is there anybody who has experience with melting of (toxic) tellurium?
Dear Dr. Nolze,
I have no experience with melting metal powders, but I checked at websites of vendors I usually buy source material from and they offer Te in the form of discs or lump. See for example:
http://www.alfa.com/en/gp140w.pgm
http://www.espimetals.com/index.php/online-catalog/443-Tellurium
http://www.lesker.com/newweb/deposition_materials/depositionmaterials_sputtertargets_1.cfm?pgid=te1
Good luck
Lior
Thanks Lior, this is a further option, although I only need a small piece of metal, and how is buying a cow if he likes to drink a glas of milk :-) ?
Maybe there is anybody around who can support me by some residual parts of a disk or a lump he dos not need anymore?
Another problem related to EBSD is the sample preparation? Does anybody has experience how tellurium can be safely prepared?
Thanks in advance!
For melting toxic powder you can use the HIP (high temperature isostatic press) with powder placed in metal can, but it will be quite expensive. You can also HIP powder already compressed to the form of capsule. Finally you can use something like the SPS (Plasma Spark Sintering) because you are working with inert gases like Ar. How big samples do You have to make?
They are only for SEM investigations (EBSD pattern selection for certain orientations).
I have an experience in preparation of tellerium of crystals. Powder is quite suitable starting product for this task. I use growth in evacuated a pyrex - glass ampoule.
The best way consists powder pressing in tablets. It is necessary for evacuation because between powder particles air remains for a long time of pumping. If you cannot press powder in tablet use any rod with flat edge to make powder more the dense. Then, after pumping of the ampoule with pressed powder you have to place an ampoule in a tube furnace. Temperature in Te-powder has to be 500 C. If you use a quartz ampoule instead of pirex then temperature can be higher. On the cold end of an ampoule I recommend to hold 200 - 300 of C. Under such conditions at cold edge of an ampoule single crystals grow. They - needles.
Good luck!
Hi Alexander, I don't need big crystals (a few microns big are OK for my purpose). A single crystal could be even adverse since I have to cut it under a certain direction. In case you have a residual piece of tellurium I would prefer not to spend much time for such a small sample.
I can grow up such crystals. It is not difficult. How urgently they are necessary?
I don't need them tomorrow, Alex. I still have to investigate Selenium, correct some papers, and need to prepare an invited talk. If you would find time during the next weeks it would be OK to me :-).
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