Definitions for "Refractory Metal"
The refractory metals include niobium (formerly known as columbium), tantalum, molybdenum, tungsten and rhenium. With the exception of two of the platinum-group metals, osmium and iridium, the refractory metals have the highest melting temperatures (greater than 2000 °C, or 3630 °F) and the lowest vapor pressures of all metals. They are readily degraded by oxidizing environments at moderately low temperatures, a property that has restricted their use as high-temperature materials. Protective coating systems have been developed, mostly for niobium alloys, to permit their use in high-temperature oxidizing aerospace applications.
A metal that has high temperature stability. Generally refers to those metals in the Periodic Groups of IVA, VA, and VIA.
Generally, any metal with a melting point above the range for iron, cobalt and nickel.
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