Niobium alloys and high temperature applications

With the launch of the Soviet satellite Sputnik in 1957; a development program for scientific studies in the United States grew to fervor second only to the Manhattan Project. Niobium, then referred to as columbium, arose from a mere laboratory obscurity to a mature alloy family in less than 20 years. The quantity of material available grew from a few pounds to tons, while the applications literally ranged the universe. The development of other technologies, specifically those of electron beam melting and vacuum systems, were critical to the path of success for niobium materials. However, once the government funded programs subsided, the niobium alloys had to find niches where not only did their properties justify use but they could be economically justified as well. Niobium and its alloys are not rare and exclusive and are readily available for commercial applications. The gamut of alloys was at one time rich and varied but through economics rather than metallurgy this variety has been significantly reduced. Today, the primary application for high temperature niobium alloys is in one form or another of rocket propulsion. Despite considerable development work towards an oxidation resistant material, niobium alloys never successfully defeated their nemesis of catastrophic oxidation. Coating technology became a significant field of its own. Coating development paralleled the waxing and waning of niobium alloys. The scope of this work specifically omits a class of niobium-titanium alloys, many developed for “super-conducting” applications, some utilized in fastener stock, and a growing use for resistance to ignition in certain elevated temperature chemical processing environments. (AU)