THE ULTRA PURIFICATION OF METALS BY ELECTRO TRANSPORT UNDER OUTER SPACE ENVIRONMENTAL CONDITIONS

摘要

A space simulation chamber capable of achieving pressures of -12 2x10 torr (N2) was designed, fabricated, and used to develop a pre-prototype electrotransport experiment. It was demonstrated that the electrotransport purification of refractory metals could be successfully performed in the non-contaminating environment of an orbiting low density materials laboratory such as the Molecular Shield Device. The zero gravity of outer space will also be advantageous since "grain-sliding" will be eliminated. As a result of the various experiments, small Quantities of the world's purest thorium metal were prepared and evaluated. The electrotransport sample assembly was tested in several environments including near zero-gravity, simulated solar radiation, coldness and darkness, and under various pressures of a representative reactive gas. Ultra-pure single crystals of a thorium were prepared and are presently being characterized. Laboratory electronics for the experiment were also developed and a totally automatic control system was used to heat the specimen. Complete assembly and line drawings of the components of the experiment and specifications for a high current power supply are contained in the Appendices.