Edwards Auto 306, cooling crucible before venting

 


This is what happens when the crucible is not allowed to cool before venting the Edwards system. The inrushing atmosphere (mainly the oxygen) reacts with the still glowing material and crucible and more or less "explodes". This was a crucible filled with alumina.
Please slowly turn down the ebeam current, take at least one minute to reduce current to zero. Then wait another minute for the material and crucible to cool down.

 


Here is another example, here the alumina has turned into a fine powder of alumina oxide and the crucible has cracked in several places. The composition of the material has been checked with SEM equipped with EDS.


Anders Liljeborg Nanostructure Physics, KTH.