Accession Number : AD0257926

Title :   HIGH-PURITY COLUMBIUM

Corporate Author : LIBRARY OF CONGRESS WASHINGTON D C AEROSPACE TECHNOLOGY DIV

Report Date : 01 JUN 1961

Pagination or Media Count : 1

Abstract : Experiments with inert-gas arc melting were made to produce high-purity solid Nb. The raw Nb powder used was 98.7% pure and contained 0.08% Fe, O.2% Pb, 0.04% Si, 0.18% C, and H2O, O2, N2, and H2. The Nb powder was dried and compacted into billets under 5 to 6 ton/sq cm pressure. Sintering was done in two stages. In the first stage, the billets were held in vacuum (0.00001 to 0.00002 mm Hg) at 1400 C for 4 to 6 hr until any remaining moisture and H were eliminated. In the second stage, the billets were resistance heated to 2300 to 2350 C and held for 8 hr in a vacuum of 0.00001 mm Hg to eliminate the remaining impurities. The refined billets were then melted in an electric-arc furnace with a Cu water-cooled hearth in an atmosphere of highpurity argon. (Author)

Descriptors :   *NIOBIUM, *PREPARATION, ARGON, CONTROLLED ATMOSPHERES, ELECTRIC ARCS, HARDNESS, IMPURITIES, MECHANICAL PROPERTIES, MELTING, POWDER METALLURGY, POWDER METALS, PRODUCTION, SINTERING, VACUUM FURNACES

Distribution Statement : APPROVED FOR PUBLIC RELEASE