| 摘要 |
It has been known that metals of groups IV-B, V-B, and VI-B of the periodic table, namely chromium, hafnium, molybdenum, niobium, tantalum, titanium, tungsten, vanadium, and zirconium and alloys thereof can be electrodeposited as dense, structurally coherent plates from a solution of the refractory metal fluoride in a molten alkali-flouride mixture in which the concentration of oxygen is reduced to and maintained at the sufficiently low level. It is shown that niobium may be plated at a lower temperature and a higher rate when the oxygen concentration is reduced to lower levels than previously attainable. The concurrent steps of electrolysis is a carbon anode, and evacuation whereby gases released from the melt at the carbon are withdrawn are shown to prepare a salt bath, and to be usable concurrently with the plating of pure niobium at a cathode, the metal depleted from the melt being replenished from a body of nobium of lesser purity maintained at a potential intermediate the potentials of the carbon anode and the niobium cathode.
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