Abstract: A phase change system comprising a reduction assembly, a cold sublimation assembly, and a hot sublimation assembly. The reduction assembly comprises a reduction crucible, a first modular crucible, and a reduction control nozzle and, when assembled, the reduction control nozzle is positioned between an open end of the reduction crucible and an open end of the first modular crucible and a protruding outlet of the reduction control nozzle extends into an activity chamber of the first modular crucible. The cold sublimation assembly comprises a collection crucible and a cold sublimation control nozzle and, when assembled, the cold sublimation control nozzle extends into an activity chamber of the collection crucible. In addition, the hot sublimation assembly comprises a hot sublimation crucible and a second modular crucible and, when assembled, the hot sublimation crucible is fluidly coupled to the second modular crucible.

Abstract: A phase change crucible that includes an inner chamber comprising an inner chamber wall extending from an inner chamber floor to an inner chamber upper end, an outer chamber comprising an outer chamber wall extending from an outer chamber floor to an outer chamber upper end, wherein the inner chamber upper end terminates beyond the outer chamber upper end and the outer chamber wall encircles the inner chamber wall, an inner collection region formed by the inner chamber wall and the inner chamber floor, and an outer collection region formed by the outer chamber wall, the inner chamber wall, and the outer chamber floor.

Abstract: A method includes forming a powder mixture from a rare earth oxide powder and a lanthanum powder, heating the powder mixture in a crucible assembly positioned in a reduced pressure environment, wherein heating the powder mixture comprises applying heat using a heating element and heating the powder mixture reduces the rare earth oxide powder into a rare earth metal that collects on a collection region of the crucible assembly. The method also includes monitoring a pressure in the reduced pressure environment using a pressure sensor and reducing the heat applied by the heating element to the powder mixture when the pressure in the reduced pressure environment is above a threshold pressure.