The corrosion of group 5A metals in flowing sodium

The corrosion of vanadium, niobium and tantalum in flowing, liquid sodium has been examined. The ternary oxides, Na4VO4 and NaVO2 have been observed on the surface of vanadium, through a matrix of sodium, by X-ray diffraction, together with an oxygen solid solution in the vanadium. For niobium and tantalum, only a single, ternary oxide corrosion product, Na3MO4(M = Nb, Ta), was observed, together with an oxygen solid solution. It has been concluded that Group 5A metals will form ternary oxide corrosion products when exposed to liquid sodium at 6000C containing more than five parts per million of oxygen. (Auth.)