What magnetic material is sintered with large corundum crucible?
But the chemical stability is good, not in vacuum. Corundum, by contrast, is much cheaper.
Corundum temperature limited, easily cracked at high temperature.
The graphite crucible is a high temperature resistant and difficult to sinter material, but the biggest problem must be used in a vacuum or a reducing atmosphere. Otherwise, graphite is easily oxidized at high temperature. And the crucibles are more expensive.
