Niobium in corrosive environments

The broadly defined corrosion behavior of niobium and niobium alloys in a variety of environments is reviewed. The environments discussed are: vacua and inert gas atmospheres containing impurities; aqueous environments - water, steam, alkalis, acids; liquid metals and metal vapors; molten salts. In each case, the basic corrosion mechanisms are outlined and data on corrosion rates are presented. The advantages and disadvantages of niobium are, wherever possibe, highlighted and discussed. Although niobium and a number of its alloys possess corrosion properties which make them interesting for a large range of uses, few major applications have yet been realized. and its alloys are reviewed and contrasts are made with the competing materials. The current and potential applications of niobium. (AU)