THE INFLUENCE OF THE CONCENTRATION OF NONMETALS IN LITHIUM ON REACTIONS WITH THE ALLOY V-1 SI-3 TI

Reactions between the vanadium-base alloy V-1 Si-3 Ti and lithium were studied at 550 degrees C in a forced convection loop made of stabiliz ed austenitic stainless steel. Preheating the lithium in contact with a titanium sponge reduced the nitrogen and carbon levels below 100 wpp m. In spite of the low concentrations of nonmetallic elements, the van adium alloy picked up these contaminants, producing a hardened surface layer. Nitrogen concentrations in the range of 10 to 70 wppm signific antly influenced the dissolution rate of the solid alloy Carbon uptake did not reach these levels. Surfaces of the alloy remained unprotecte d at the lowest nitrogen levels in the lithium. At higher contents, a protecting compound was detected at the surface of the alloy, reducing the dissolution rare during the corrosion test. Dissolution of vanadi um and the minor alloying elements became evident when nitrogen concen tration was increased further: Material losses from V-1 Si-3 Ti was on ly one tenth of that seen from either austenitic or ferritic stainless steels at the same temperature and flow velocity.