Surface protection to prevent the formation of iron oxide on ferrous parts and equipment. This can be achieved by coating, surface treatment, electroplating, chemicals, cathodic rust prevention and other methods. Overview: Surface protection to prevent the formation of iron oxide on ferrous parts and equipment. This can be achieved by coating, surface treatment, electroplating, chemicals, cathodic rust prevention and other methods. Methods
1. Surface pretreatment;
2. Electroplating;
3. Thermal spraying;
4. Hot-dip plating;
Surface transformation modification technology, 5.
6. Surface diffusion penetration technology
7. Corrosion inhibitor (VCI gas-phase corrosion inhibitor)
8. Use of anti-rust oil
9. Use of passivation liquid
10. Immersion in high-concentration rice water
11. Blue-burning, enamel-burning
12. Plating of other metals (Zn, Al)
Surface pretreatment methods for rust-proofing objects:
1) Surface cleaning: It is necessary to select an appropriate cleaning method according to the nature and situation of the surface of the object to be rust-proofed. Commonly used methods include solvent cleaning, chemical cleaning, and mechanical cleaning.
2) After the surface is dry and cleaned, it is dried with filtered dry compressed air, dried in a dryer at 120 to 170 °C, or wiped dry with clean gauze.
How to apply anti-rust oil:
1) Immersion method: Some small items are immersed in anti-rust grease and a layer of anti-rust grease is applied to the surface. The oil film thickness can be achieved by controlling the temperature and viscosity of the anti-rust grease.
2) For outdoor construction machinery and products with special shapes that are not suitable for immersion or spraying, the brush application method is used, so when applying with a brush, be careful not to stagnate the oil but also to miss any spots.
3) Spray method: Some large objects to be rust-proofed may not be able to be immersed in oil, and generally spray using compressed air of about 0.7 Mpa that has been filtered in a clean air area. The spray method is suitable for the use of anti-rust oil diluted with a solvent or thin-layer anti-rust oil, but fire prevention and labor protection measures must be thoroughly taken.
What are the main factors that affect metal corrosion?
Metal corrosion is caused by a variety of internal and external factors, which can be summarized as follows:
① The chemical composition and structure of the metal material itself.
② Metal surface finish (corrosion of batteries due to differences in oxygen concentration).
③ The composition and pH value of the solution that comes into contact with the metal surface.
④ The surrounding temperature and humidity.
⑤ Various environmental media that come into contact with the metal surface.
Why does hand sweat cause metal to rust?
Human sweat is a colorless, transparent or pale yellow salty liquid with a pH value of 5 to 6. In addition to sodium, potassium, calcium and magnesium salts, it also contains small amounts of organic acids such as urea, lactic acid and citric acid. When sweat comes into contact with metal, a sweat film is formed on the metal surface, and the sweat film has an electrochemical effect on the metal, causing it to corrode. Since it is inevitable that people will sweat, production personnel should wear gloves or finger cots or not touch the product with their bare hands.
Passivation principle
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The passivation mechanism can be explained by thin film theory. That is, passivation is due to the interaction of metal and oxidation properties, which produces a very thin, dense and good coating property on the metal surface, which is tightly adsorbed on the metal. Passive film on the surface. This film exists as a separate phase, which is usually a compound of metal oxide. It plays a role in completely isolating the metal from the corrosive medium and preventing the metal from coming into contact with the corrosive medium, and the metal basically stops dissolving and forms a passive state that prevents corrosion.
Car rust prevention
Tips to prevent car rust: Reduce the use of car clothes
When you park your car outdoors in the event of encountering wind and rain, the inner layer of the car cover will repeatedly hit the paint, and when the wind and sand blow into the car cover, countless small scratches will be left on the car body. The is larger. Over time, the paint will turn black. In addition, after a sandstorm, do not wipe the sand on the car body directly with a duster or rag, but rinse the car body with clean water. This is to prevent the sand on the duster or rag from scratching the painted surface. .
Tips to prevent car rust 2. Apply toothpaste to prevent rust
If your car has scratches, use regular toothpaste to treat the scratches. Here's how to do it: Gently apply toothpaste to the scratched area in a circular motion. Reapply after it rains or after washing the car. Doing this will generally reduce scratches and marks, and also insulate and rust, so it will be fine in the short term.
Tip 3 to prevent car rust: Use sealing glaze on the soft painted surface of the car
For vehicles with soft painted surfaces, sand particles on the body may hit the car when driving at high speeds, causing fine scratches. For this type of car, applying sealing glaze to the body will form a strong mesh-like protective film and improve the hardness of the painted surface. The effect will last for about a year. Of course, coatings can have the same effect. This trick is widely used to prevent cars from rusting.
