Rare earth fluorides, metals and slag have strong chemical activity, so the crucible material used must be resistant to corrosion by halogens and their compounds at high temperatures and does not interact with rare earth metals. It can be used for a long time in inert atmosphere.

Below we list the chemical stability of different crucible materials to rare earth metals and halides.

Magnesium oxide

It is relatively stable at 1200 ℃. It was used in the village of RECl3-KCl molten salt electrolyzer.

Calcium Oxide

Stable within 1000℃

Beryllium oxide

Can be used up to 1250 ℃

High purity zirconia

No higher than 1700 ℃, stable in vacuum and inert atmosphere

Alumina, Silicon Oxide

Reacts with molten metal at high temperatures

Tantalum Metal

Stable in vacuum and inert gas before 1700 ℃, but it has obvious effect with scandium and lutetium

Niobium Metal

1% -2% dissolved in rare earth metal at 1500 ℃ in vacuum and inert gas paper

Molybdenum Metal

Stable before 1400 ℃ in inert gas

Tungsten Metal

Slowly corroded at high temperature in an inert atmosphere, but stable to halides

Graphite, Carbon

Slow action on rare earth metals, but stable to halides

Cerium Sulfide

Stable to cerium at high temperature and halide at 1000 ℃

Titanium nitride (70%) + titanium oxide (30%)

More stable than cerium sulfide