Columbium (Cb), or niobium, is a grey, ductile, tarnish-resistant and superconductive metal with a melting point of 2468°C. The name niobium (Nb) was officially adopted in 1951 by the International Union of Pure and Applied Chemistry, after 100 years of controversy. In North America many metallurgists and metal dealers still refer to the metal as columbium. Columbium is an important alloy in high-strength, low-alloy (HSLA) steels. High-purity columbium products are used in superalloys for the AEROSPACE INDUSTRY and in superconductor magnets for powerful generators.
The main sources of columbium are the minerals pyrochlore and columbite; extensive reserves are found in Brazil, Canada, Nigeria and Zaire. As of 1994, the company converts its concentrate into Ferroniobium, an intermediate product used by the steel industry (seeIRON AND STEEL INDUSTRY ). Several large deposits, located mainly in Québec, could be developed in future.
See alsoMINERAL RESOURCES.