What is the difference between hot galvanizing and electroplating?


China is a big steel country, and its annual steel output ranks top in the world. Especially in the northern part of China, the heavy industry is developed, steel plants and metallurgical plants are everywhere, accounting for most of the steel industry.

When it comes to the practical application of steel and iron, there must be the key word galvanizing. Today, I will mainly talk about the galvanizing process. People who are familiar with it may think it's superficial after reading it. It's just to add some simple knowledge to people who don't know it.

When it comes to galvanizing, there are many processes, but hot-dip galvanizing and electro galvanizing are common and commonly used. Today, I'd like to talk about them.

Baidu Encyclopedia said: zinc is a chemical element, its chemical symbol is Zn, its atomic number is 30, in the periodic table of chemical elements in the fourth cycle, the IIb group. It's a light gray transition metal. Zinc (zinc) is the fourth "common" metal, next to iron, aluminum and copper, but the most abundant elements in the crust are oxygen, silicon, aluminum, iron, calcium, sodium, potassium and magnesium. The appearance is silvery white, which plays an indelible role in battery manufacturing in modern industry, and is a very important metal. In addition, zinc is one of the essential microelements in human body, which plays an important role in the physiological process of human growth and development, reproductive genetics, immunity, endocrine and so on.

Zinc (Chinese pronunciation: X ī n), its name "zinc" comes from Latin zincum, which means "white thin layer" or "white sediment". The chemical symbol is Zn, which has an atomic number of 30 and a relative atomic mass of 65. Zinc is a silvery white light blue metal with a density of 7.14g/cm3 and a melting point of 419.5 ℃. At room temperature, it is brittle; at 100-150 ℃, it becomes soft; when it exceeds 200 ℃, it becomes brittle again. The chemical properties of zinc are active. In the air at room temperature, a thin and dense basic zinc carbonate film is formed on the surface, which can prevent further oxidation. When the temperature reaches 225 ℃, zinc oxidizes violently.

Zinc is difficult to burn in the air and gives off a strong white light in oxygen. Flame reaction: blue-green flame is emitted, because there is a layer of zinc oxide on the surface of zinc, white smoke is emitted during combustion, and the main component of white smoke is zinc oxide, which not only blocks the combustion of zinc, but also refracts the flame color to form a pale light, so there is no blue-green flame in the combustion of zinc block in the laboratory. Zinc is easy to dissolve in acid, and also easy to replace gold, silver and copper from solution. The melting point of the oxide film of zinc is high, but the melting point of the metal zinc is very low. Therefore, heating the zinc sheet on the alcohol lamp makes the melting of the zinc sheet soft, but it does not fall down. It is precisely because of the role of the oxide film. Zinc is a common non-ferrous metal, which is the latest one among the seven ancient non-ferrous metals such as copper, tin, lead, gold, silver, mercury and zinc. It is the fourth common metal, next to iron, aluminum and copper. Zinc can be made into alloys with a variety of non-ferrous metals, the most important of which is brass composed of zinc and copper, tin, lead, etc., and die-casting alloy composed of aluminum, magnesium, copper, etc. Zinc is mainly used in steel, metallurgy, machinery, electricity, chemical industry, light industry, military, medicine and other fields.

The chemical explanation and industrial use of zinc are briefly introduced in the above. The chemical properties of zinc are active. In the air at room temperature, a thin and dense basic zinc carbonate film is formed on the surface, which can prevent further oxidation. So as to effectively extend the service life of the articles and the anti acid, alkali and anti-corrosion ability. It can be regarded as a protective treatment for the appearance of industrial products.