(1) Choose corrosion-resistant materials
Mainly use non-ferrous metal alloys and stainless steel.
(2) Prefabricated metal (alloy) or non-metal covering layer on metal surface
1. Conversion coating: blackening (bluish), phosphating, anodic oxidation;
2. Surface alloying: nitriding, sherardizing, siliconizing, aluminizing, chromizing, etc.;
3. Metal covering layer: electroplated metal, sprayed metal, hot dip plating, electroless plating, etc.;
4. Non-metallic coating: enamel, ceramics, paint, plastic, rubber, etc.;
5. Coating anti-rust materials: anti-rust water, cutting fluid, vapor phase corrosion inhibitor, peelable plastic, anti-rust oil, anti-rust grease, etc.
(3) Cathodic Protection Law
The electrochemical method of sacrificing the anode and protecting the cathode. For example, in seawater, the magnesium block is used as the anode to connect with the steel plate, and the steel plate becomes the cathode to be protected by passing an electric current. Underground pipelines and chemical equipment are also another anode outside and are energized to protect the steel parts (cathode).
(4) Controlling the environment and preventing corrosion
1. Use dehumidifiers and humidification to lower the temperature, control the relative humidity below 60~70%, and metal corrosion will slow down; when the relative humidity is below 60%, non-metals will not be moldy and deteriorate;
2. Nitrogen filling or vacuum packaging can delay corrosion;
3. Built-in corrosion inhibitor in the package;
4. When steel products are heated in an electric furnace (high temperature), a protective atmosphere or real heating is formed in the furnace.
In summary, there are many ways to prevent metal corrosion, and many factors should be considered after judging the choice, such as: the working environment of the parts, the service conditions of the parts, the safety of production, the degree of pollution to the environment, and the manufacturing cost.