Thermal Behavior in Vacuum Zone Refining

Abstract

The temperature distribution and the total radiated power are computed for a bar undergoing zone refining in vacuum, using a one-dimensional analysis. Radiated power experiments were performed on Al, Ge, Gd, Si, Ni, Fe, Pt, Pd, V, Mo, Ta, and W using an electron-bombardment zone-refining furnace operated with space-charge limited current. The experiments agreed well with the prediction P=4π(eσk/5)12R32T52 for a very thin bar with an infinitesimal zone length.