Rhenium is classified as a scarce refractory metal. It has the second highest melting point of any of the metals and has relatively high density. Rhenium is produced as a powder from molybdenite, which also contains rhenium sulfide. The rhenium powder is consolidated by pressing and resistance sintering in a vacuum or hydrogen atmosphere. Rhenium […]
The melting point of chromium is the lowest of the abundant refractory metals, but it is more than 700 degrees above that of iron. The density of chromium is slightly less than that of iron. At elevated temperatures, it acquires an adherent oxide film on the surface that tends to protect it from further oxidation […]
The melting point of vanadium is about 1000 degrees lower than that of columbium, so there is much less interest in vanadium for high temperature applications than in the abundant refractory metals. Pure vanadium has only recently become available in quantities large enough for thorough studies of its physical and mechanical properties and for alloy […]
Niobium has a melting point of 4474 F, which is 256 degrees lower than that of molybdenum. Development of niobium metal and its alloys for elevated-temperature structural applications was started only a few years ago, but considerable progress has been made since then. One factor that has been important in the development of niobium is its low […]
Molybdenum. As shown in Table 2, the melting temperature of molybdenum is 695 degrees below that of tantalum. Because of its high melting point and relative abundance in the United States, it was the first of the refractory metals considered in this country for high-temperature structural applications. The primary use of molybdenum had been as […]
Copyright © 1994-2019 Stanford Advanced Materials, All Rights Reserved.