How to classify metals?Is the black metal really black?

Since the beginning of the 20th century in the era of industrialization, the era of information, globalization and knowledge, the development of social productivity has continued to improve the requirements of materials. At the same time, due to the rapid development of science and the maturity of material production technology, other various materials It can develop rapidly, but the status of metal materials as the most important structure and functional materials is always difficult to shake.

In various materials, metal can be described as the role of "top beam pillar". Looking at your surroundings, there must be something made of metal or participation. An example of the most image is that everyone cannot be separated from the mobile phone. Without metals, it will become a useless brick.

Copper coil pictures on the circuit board Source: Veer gallery

Black is colorful black

When it comes to metal, what scenes will appear in your mind? Is it the glittering necklace head jewelry, or is it shining with metallic luster pots and pans? I do n’t know if you find it. Whenever the metal is mentioned, we seem to never associate it with black, but the “black metal” is indeed a large category in the metal!

The word "black" can easily make people mistakenly make black metals that must be black, and non -ferrous metals must be colorful. Based on this, many people think that silver -white iron, chromium and silver -gray manganese should not be "black" metal. So why do the three and its alloys belong to the category of black metals?

The reason is: black metal is the collective name of iron, chromium and manganese in the industry, and also includes the alloy of these three metals. In fact, pure iron and chromium are silver -white, while manganese is silver -gray. Because the surface of the steel is usually covered with a layer of black four -iron oxidation, and manganese and chromium are mainly applied to smelting black alloy steel, it is mistaken for "black" metal.

Steel and gold represent the representative black metal and non -ferrous metal pictures. Source: Veer gallery

The dispute between the two major metal martial arts

For metals, the official definition is "material with gloss, good conductivity, thermal conductivity and mechanical properties, and positive resistance temperature coefficients."

Metal is a big family, with a total of 86 members in this big family. Usually people divide them into two "martial arts" according to their colors and properties: black metals and non -ferrous metals. Black metals mainly refer to iron, chromium, manganese, and its alloys, such as steel, raw iron, iron alloy, cast iron, etc., while non -ferrous metals refer to metals other than black metals, also known as non -iron metals, which are iron, chromium, manganese metals other than metals such as iron, chromium, and manganese. The collective name of all metals.

Elemental period table picture source: Veer gallery

Not only are they different names, their output is also very different! Because of the large variety of non -ferrous metals, the number of minerals is much more than black metals. Although the black metal has a small mine, the output of each mine is many, which makes the total output of black metals reaching 95%of the world's metal output! And three metals such as iron, chromium, and manganese are the main raw materials of smelting steel, and steel occupies an extremely important position in the national economy, and can also be used as an important symbol of national strength.

Interesting name

"Nonferrous Metals" English translates as "Nonferrous Metals", which corresponds to the English translation "Ferrous Metals" of "Black Metal". According to an old gentleman who has worked in the non -ferrous metal industry for a long time, the process of translating "Ferrous Metals" and "Nonferrous Metals" was also an interesting story.

Scholars who translated "Ferrous Metals" and "Nonferrous Metals" believed that if they were directly translated as "iron metals" and "non -iron metals", or "iron -containing metals" and "non -iron metal" The accuracy of the translation is not concise enough, and it is also very mouthful in use. So the scholar jumped out of the inertial thinking and set out from the optical nature of the metal, and created in the translation.

The pure iron is silver -white, but the iron that people often see in their daily work and life are black. This is because the surface of the iron covers a layer of black oxidation film: four oxidation three iron. It is precisely because of this layer of oxide that the iron impression has left people's black impression, so from this perspective, the "Ferrous Metals" is translated into "black metal".

Rust steel and pure steel picture Source: Research Department of the Advanced Iron Materials Research Department of the Chinese Academy of Sciences

With the existence of "black metal", considering that silver is white, gold is gold, copper is yellow, and lead is gray. Metal". Since then, "black metals" and "non -ferrous metals" have become "Ferrous Metals" and "Nonferrous Metals" in Chinese.

Metal, the "top beam column" of social development

Metal materials can be said to be a promoter in the development of human society, because it plays a pivotal role in various transition periods of human society. In the history of human society, the copper era and iron era that appeared in the stone artifact period were based on the application of metal materials as a significant symbol of its era.

Bronze Beast Facial Ding Picture Source: Forbidden City Museum

After the Second World War, the advancement of science and technology promoted the development of new materials. Ball and ink cast iron, alloy cast iron, alloy steel, heat -resistant steel, stainless steel, nickel alloys, titanium alloy and hard alloy were successively developed and used Production in actual. In modern times, the research and development of metal materials is not limited to traditional pure metal and pure alloy directions. With the improvement of basic theory and process technology, new metal materials have developed rapidly. These include high-temperature structural materials such as nano-metal, high/medium entropy alloys, directional solidaries and single crystal alloys, metal base composite materials, and shape memory alloys. [1-4].

A variety of metal materials have become an important material foundation for the development of human society. Agricultural modernization, industrial modernization, national defense and science and technology modernization are inseparable from the support of metal materials. The tip weapons such as the guidance, the rocket, the satellite, the nuclear submarine, and the components or components required by the tip technologies such as atomic energy, television, communication, radar, electronic computers and other cutting -edge technologies are made of metal.

At present, many countries in the world, especially industrial developed countries, compete for the development of metal and non -ferrous metal industries, and increase the strategic reserves of metal. It can be said that metal materials are the essential basic materials and important strategic materials for the development of the national economy, the daily life of the people, and the development of science and technology.

Produced: Popular Science China

Author: Liu Tengyuan (Institute of Metal Research of the Chinese Academy of Sciences)

Producer: China Science Popularization Expo

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