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Naturally occurring tungsten consists of four stable isotopes (182 W, 183 W, 184 W, and 186 W) and one very long-lived radioisotope, 180 W. Theoretically, all five can decay into isotopes of element 72 by alpha emission, but only 180 W has been observed to do so, with a half-life of (1.8 ± 0.2) × 10 18 years; [36] [37] on average, this yields ...
Wolframite is highly valued as the main source of the metal tungsten, a strong and very dense material with a high melting temperature used for electric filaments and armor-piercing ammunition, as well as hard tungsten carbide machine tools. During World War II, wolframite mines were a strategic asset, due to its use in munitions and tools. [13]
The Wolfram Crisis (Spanish: Crisis del wolframio) was a diplomatic conflict during World War II between Francoist Spain and the Allied powers, which sought to block Spanish exports of tungsten ore to Nazi Germany. "Wolfram" is an alternate name for tungsten, a strategic material used in anti-tank weapons and machine tools.
Ferrotungsten is relatively expensive, with the prices around $31–44 per kilogram of contained tungsten. [4] During World War 2, over 21,000,000 lb of Ferro-tungsten and other ferroalloys were shipped to Russia on lend-lease. [3] The cost was more than $12,000,000. Ferrotungsten comes from rich ore raw materials primarily of wolframite or ...
For the production of the tungsten heavy alloy, binder mixtures of nickel and iron or nickel and copper are widely used. The tungsten content of the alloy is normally above 90%. The diffusion of the binder elements into the tungsten grains is low even at the sintering temperatures and therefore the interior of the grains are pure tungsten. [18]
Based on the "oral history of the zombie war" of the same name by Max Brooks, World War Z was a surprise hit at the box office when it debuted in 2013, making over $500 million worldwide.
Tungsten was used in hammer throw balls at least up to 1980; the minimum size of the ball was increased in 1981 to eliminate the need for what was, at that time, an expensive metal (triple the cost of other hammers) not generally available in all countries. [182] Tungsten hammers were so dense that they penetrated too deeply into the turf. [183]
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