PREPARATION OF ZIRCONIUM-NIOBIUM ALLOY BY CARBIDE-OXIDE REACTIONS

摘要

This investigation is concerned with the-direct preparation of Zr-Nb master alloys by reaction between ZrC and Nb205. The thermodynamics of the reaction are discussed. Starting with 2 different compositions corresponding to 5% and 15% excess oxygen over the stoichiometric requirements, and adopting progressive heat-soaking under high dynamic vacuum, followed by electron beam melting, zirconium-niobium alloys low in carbon and oxygen have been prepared. The influence of initial oxygen excess and time of heat soak on the final purity of the alloy has been examined. The overall material balance for the reaction indicates removal of oxygen both through carbothermic reduction (as CO) and through sacrificial deoxidation (as ZrO).