Views:8 Author:Site Editor Publish Time: 2018-06-06 Origin:Site
Rare elements are the general term for the elements in nature, which are sparsely populated, sparsely distributed, and rarely used by humans. They are often used to make special metal materials and are critical materials in the industrial fields of aircraft, rockets, and atomic energy.
There are many tough guys in the rare metal family. They are as if they have smashed bones, not only a high melting point, but also a strong ability to resist corrosion. Even when exposed to air, it is not easily oxidized.
Tungsten light bulb
If you rank these tough guys in rare metals, there is no doubt that tungsten should be the first "tough guy." The melting point of metal tungsten is the highest of all metals up to 3410°C. It is this feature that people have used to use it as a filament material. For heat-resistant metal tungsten, enduring high temperatures of around 2000°C can't be avoided. In the production of hard alloys, special steels and other products, people use tungsten metal as a material. It is widely used in the defense industry, aerospace, information industry and other fields, known as the "industrial teeth." China is a major producer of tungsten, with a reserve of 5.2 million tons of tungsten resources, which accounts for 65% of the world's total reserves. Its output and exports rank first in the world.
In the big family of rare metals, the second toughest guy is the metal rhenium. The melting point of the metal rhenium is 3180°C, which is also an element that is not afraid of heat. What needs to be specified is that metal rhenium is a genuine rare element. The metal rhenium contained in the earth's crust is very rare and dispersed. Its content is only a little higher than that of thorium and radium. The concealment technology of metal coffins is also quite good. In the half-century after Mendeleev discovered the periodic table of elements, people took pains to find their shadows. It was not until 1925 that it was "brought" by Germany. It can be said that the metal rhenium is the last element discovered by people in nature.
The melting point of the metal osmium is 3045°C, which is the third "tough guy" in the rare metal family. With a density of up to 22.4 g/cm 3 , metallic osmium is the heaviest metal in nature.
After the introduction of the top three, we are talking about the low-key fourth "tough guy", which is a metal tantalum with a melting point of 2996 °C.
In addition, in the rare metal family, molybdenum, yttrium and the like are also the metals that have a melting point above 2000°C. Molybdenum is an essential trace element in the body, animals and plants. In an adult's body, about 9 milligrams of molybdenum is contained, and most of these 9 milligrams are distributed in the liver and kidneys. Under the action of molybdenum, plants can fix nitrogen and convert nitrogen into an absorbable form that nourishes plant growth. When smelting all kinds of alloy steel, stainless steel, heat-resistant steel, super alloy, molybdenum is an essential material. It is called "war metal" and has a very wide range of applications in the military industry. The melting point of the metal yttrium is 2233°C, and it is also a famous heat-resistant family. According to research, the melting point of an alloy of tantalum is about 4215 °C, which is the highest known melting point material.
Although these "tough guys" in the rare metal family have their own temperaments, they also have their own advantages and energy, and they play an important role in different fields.