The most common way to prevent metal parts from rusting is to put "clothing" on the iron-paint or plate other metal parts that are not easy to rust. For example, a car is wearing shiny spray paint; the heating pipe is coated with aluminum paint; the tinplate used for canning is plated with tin; the tinplate on the roof is coated with a layer of zinc; your fountain pen is plugged in. , Plated with a layer of chromium or nickel. A more thorough method is to inject iron with a "strong heart needle"-adding other metals to make a stainless alloy. 

The famous stainless steel is made by adding a little nickel and aluminum to the steel. Into the alloy.

Anti-rust should take appropriate methods according to the cause of metal corrosion. Commonly used methods are:

[Change the internal structure of the metal] For example, manufacturing various corrosion-resistant alloys, such as adding chromium and nickel to ordinary steel to make stainless steel.

[Protective layer method] Cover the metal surface with a protective layer to isolate the metal product from the surrounding corrosive medium to prevent corrosion. Such as:

  • 1. Coat the surface of steel parts with engine oil, petroleum jelly, paint or cover with enamel, plastic and other corrosion-resistant non-metallic materials.
  • 2. Use electroplating, hot-dip, spraying and other methods to plate a layer of non-corrosive metals on the surface of steel, such as zinc, tin, chromium, nickel, etc. These metals often form a dense oxide film due to oxidation, thereby Prevent water and air from corroding steel.
  • 3. Chemical methods are used to form a fine and stable oxide film on the surface of steel. For example, a fine black ferroferric oxide film is formed on the surface of steel parts such as machine parts and guns.

[Electrochemical protection method] Use the principle of galvanic cell to protect the metal and try to eliminate the galvanic corrosion that causes galvanic corrosion. Electrochemical protection law is divided into two categories: anode protection and cathodic protection. Cathodic protection is the most widely used method.

[Treatment of corrosive media] Eliminate corrosive media, such as frequently cleaning metal equipment, placing desiccant in precision instruments, and adding a small amount of corrosion inhibitor that can slow down the corrosion rate in corrosive media.

[Electrochemical protection] The protected metal is used as the cathode of the corrosion battery to prevent it from being corroded, so it is also called cathodic protection. This method mainly includes the following two:

[Sacrificial anode protection method] This method is to connect an active metal (such as zinc or zinc alloy) to the metal to be protected. When galvanic corrosion occurs, this active metal acts as a negative electrode to undergo oxidation reaction, thereby reducing or preventing Protect metal from corrosion. This method is often used to protect steel piles and shells of ships in the water, such as the protection of steel gates in the water. Usually, several pieces of zinc are welded below the waterline of the shell of the ship or on the rudder near the propeller. To prevent corrosion of the hull, etc.

[Impressed current protection method] Connect the metal to be protected to the negative pole of the power supply, and choose another conductive inert material to connect to the positive pole of the power supply.

After electrification, the accumulation of negative charges (electrons) on the metal surface, thus inhibiting the metal from losing electrons to achieve the purpose of protection. This method is mainly used to prevent corrosion of metal equipment in the soil, sea water and river water.

Another method of electrochemical protection is called anode protection, which is the process of passivating the anode within a certain potential range by applying voltage. It can effectively block or prevent the corrosion of metal equipment in acids, alkalis, and salts. .