“Tough Guys” in Rare Metals

“Tough Guys” in Rare Metals

In the rare metal family, there are many members with "stubborn personalities". They not only have high melting points, but also have strong corrosion resistance and are not easily oxidized in the air, so they are called "tough guys" in metals.

The melting point of tungsten is as high as 3410 ° C, which is the highest of all metals, so it can be used as a filament material. Withstanding high temperatures of 2000°C is a piece of cake for tungsten. Metal tungsten is mainly used in cemented carbide, special steel and other products, and is widely used in the defense industry, aerospace, information industry, and some people give it the title of "the tooth of the industry".

The second melting point is the metal rhenium, which is 3180 ℃. It is worth mentioning that rhenium is a truly rare element. Its content in the earth's crust is very rare and dispersed, only higher than those of protactinium and radium. Therefore, it is the last element found in nature. Since Mendeleev discovered the periodic law of elements, scientists failed to find it for more than half a century until it was discovered by German chemists in 1925.

The third melting point is the metal osmium, which is 3045 ℃. At the same time, it is also the heaviest metal in nature, with a density of up to 22.4 g/cm3. In fourth place is the metal tantalum, which has a melting point of 2996°C.

Metals with a melting point over 2000 ° C, as well as molybdenum, hafnium, etc. Molybdenum is an essential trace element for humans, animals and plants. The total amount of molybdenum contained in an adult's body is 9 mg, with the highest content in liver and kidney. Plants can fix nitrogen under the action of molybdenum and convert nitrogen into a form that can be absorbed. Molybdenum is mainly used for refining various alloy steels, stainless steels, heat-resistant steels and super alloys. It is widely used in the military industry and is also known as "war metal". The melting point of metal hafnium is 2233°C. It is worth mentioning that an alloy of hafnium, Ta4fC5, is the substance with the highest known melting point, about 4215°C.

Post time: Jun-06-2022