What Is Metal Cladding?

The base material of the workpiece is immersed in a molten metal bath, and interacts with the molten metal to generate. Commonly used are metal coatings such as zinc, aluminum, tin, lead, lead-tin alloy and other metal coatings produced by the iron and steel industry. The largest number. Hot dip tin has gradually been replaced by electrochemical tin plating. In mechanical manufacturing, steel products that work outdoors and have less strict size requirements but high corrosion resistance and low cost must also be coated with hot-dip zinc and hot-dip aluminum. Hot-dip zinc has a long history. In the past, it was mostly used to make corrugated iron, hot-dip zinc wire and containers required by the construction industry. In some modern countries, signal signs along railways, fixed facilities on both sides of roads, and transmission towers are also protected by hot-dip zinc layers. In addition to being resistant to the industrial atmosphere, especially the corrosion of sulfur-containing gases and furnace gases, hot-dip aluminum coatings can also be heated to 500 ° C without significant changes. They are used in petrochemical equipment and boiler manufacturing.

Metal coating

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Metal coatings Metal coatings made by various methods are commonly referred to as electroplating, metal spraying, and surface alloying methods. Hot-dip metal coatings, coatings, and vapor deposition methods also have certain applications.

The base material of the workpiece is immersed in a molten metal bath, and interacts with the molten metal to generate. Commonly used are metal coatings such as zinc, aluminum, tin, lead, lead-tin alloy and other metal coatings produced by the iron and steel industry. The largest number. Hot dip tin has gradually been replaced by electrochemical tin plating. In mechanical manufacturing, steel products that work outdoors and have less strict size requirements but high corrosion resistance and low cost must also be coated with hot-dip zinc and hot-dip aluminum. Hot-dip zinc has a long history. In the past, it was mostly used to make corrugated iron, hot-dip zinc wire and containers required by the construction industry. In some modern countries, signal signs along railways, fixed facilities on both sides of roads, and transmission towers are also protected by hot-dip zinc layers. In addition to being resistant to the industrial atmosphere, especially the corrosion of sulfur-containing gases and furnace gases, hot-dip aluminum coatings can also be heated to 500 ° C without significant changes. They are used in petrochemical equipment and boiler manufacturing.

The coating technology was first used in the manufacture of ornaments. For example, a malleable precious metal such as gold and silver was hammered into a thin foil and coated on brass or bronze. The thermo-mechanical action was used to make them have a good combination at the interface. It has been widely used in industry since the 1930s.

Hot isostatic cladding is the use of thermo-mechanical action to first make a metal with good ductility that is resistant to high temperature oxidation, hot corrosion and brittle cracking. Its thickness is between 25 and 250 microns. The first and second-stage blades of alloy gas turbines are heated in an autoclave filled with inert gas for a long period of time, so that there is a slight mutual diffusion between the coating material and the substrate. The coating material under study may contain Nickel-chromium alloy, nickel-chromium-aluminum alloy, iron-chromium-aluminum-yttrium alloy dispersing hafnium dioxide (2%), and the like.

A coating formed by the condensation of metal vapor on a base material. When the vacuum evaporation method is used, the evaporation is performed at a pressure of 10 (~ 10 (Pa), and a thick layer of aluminum is pre-impregnated on the thicker tungsten wire by using electric heating to cause the aluminum vapor source to be deposited on the cold workpiece surface. Initially, this method has been used to make reflective mirrors required for large-aperture astronomical telescopes. Modern applications are mainly applied to the electrode surfaces and reflective mirrors of electronic devices, ceramics and piezoelectric crystals. It can also be used to produce aluminum on paper plastic and steel strips. , Zinc, gold, silver and other coatings is sputtering, that is, in the 10 (~ 10 (Pa vacuum), the gas generates a discharge phenomenon between the electrodes, positively charged gas ions are bombarded at 100 to 10,000 electron volts The cathode, which forms a gas phase beam of metal atoms, is deposited on the surface of a cold or heated workpiece to form an extremely thin but dense metal coating. Magnetron sputtering technology has been able to deposit faster on large surface workpieces A more uniform metal coating, such as chromium sputtered on plastic, can be used in the automotive industry. Ion plating methods have developed rapidly. With this method, the sample to be plated is used as the cathode with an applied potential of 3000 to 5000 volts. Heating by resistance, electron beam Or induction heating generates positively charged metal vapor, which becomes positive ions in the glow discharge area, which can cover the surface of the workpiece with higher energy than the sputtered particles. The vapor deposition coating method is not only used for metals, but also applicable For inorganic and plastic coatings.