Thermal Behavior in Vacuum Zone Refining

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 ${\text{P=4π(eσk/5)}}^{\frac{1}{2}}{R}^{\frac{3}{2}}{T}^{\frac{5}{2}}$ for a very thin bar with an infinitesimal zone length.