from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A rare, dense, silvery-white metallic element with a very high melting point used for electrical contacts and with tungsten for high-temperature thermocouples. Atomic number 75; atomic weight 186.2; melting point 3,180°C; boiling point 5,627°C; specific gravity 21.02; valence 1, 2, 3, 4, 5, 6, 7. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A metallic chemical element (symbol Re) with an atomic number of 75.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a rare heavy polyvalent metallic element that resembles manganese chemically and is used in some alloys; is obtained as a by-product in refining molybdenum
Sometimes platinum is combined with a second catalyst (bimetallic catalyst) such as rhenium or another noble metal.
High levels of refractory elements such as rhenium can make the alloys prone to the formation of what are known as deleterious topologically close packed
By tweaking the mix of other hardening additives like nickel and molybdenum, which are cheaper and more abundant, GE was able to cut the rhenium content in its jet-engine blades to 3% from 6%.
The metals in question range from the truly rare, such as rhenium, to more abundant but hard-to-process elements such as rare-earth metals, a collective name for 17 minerals used in products like iPhones, the Toyota Prius, vacuum cleaners and energy-efficient light bulbs.
The plan builds on the success GE had in paring rhenium from the steel superalloys used in its jet engines and gas turbines.
While those steps reduced the company's rhenium use by two-thirds, GE also started a global recycling partnership with other jet-engine makers to further cut the need for new metal.
GE says its success with rhenium led the company to examine how it could pare usage of other scarce metals.
Seven months later, Rusnano approved 79 million rubles ($2.6 million) in venture funding for Mr. Petrik's project to extract the chemical element rhenium from scrap.
At a hearing on the stockpile last July, a Defense Department official told Congress that the price of rhenium, whose heat-resistant qualities help jet engines operate at higher speeds, at one point shot up 1,000%.
There are some metals that I might import into the EU once every two or three years (berylllium and rhenium, to give examples).
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