What are the Anticorrosive Methods of Anticorrosive Coatings?

From:Linshang Time:2020/04/02 11:00:00 Browse:51
There are three main ways for coatings to protect the coating, namely shielding anti-corrosion, passivation anti-corrosion and electrochemical anti-corrosion. It can be said that the application design mechanism of coatings cannot be separated from these three anti-corrosion methods.

1. What are the ways of coating anticorrosion?

(1) Shielded anticorrosion

As its name implies, the role of shielding is one of the basic characteristics of coatings, but there are good and bad shielding. Some coatings have strong shielding properties and can resist acids, alkalis and solvents. Some coatings have weak shielding properties. Long-term immersion in water can also cause rust, the difference is so large, the main reason is the different design principles for shielding.
       Commonly used high-shielding paints such as epoxy mica intermediate paint and epoxy glass flake paint. Both use mica iron oxide and glass flakes as shielding media. The flake pigments form a structure with a maze effect, which prolongs the penetration of corrosive media The way of transparent coating can more effectively block the corrosive medium and achieve the purpose of anticorrosion.

(2) Passivation and anticorrosion

The principle of passivation can protect the substrate and isolate the corrosive medium. The mechanism of passivation is due to the interaction of metals with oxidizing substances. A strong passivation film adsorbed on the metal surface is formed on the metal surface during the action. It has the function of completely separating the metal from the corrosive medium, preventing the metal from contacting the corrosive medium, so that the metal basically stops dissolving and forms a passive state to prevent corrosion.

(3) Electrochemical corrosion protection

Electrochemical anticorrosion mainly uses the gain and loss electrons of active metals to protect iron. The common active metal is zinc. In the presence of a corrosive medium, zinc and iron form a galvanic cell effect. Zinc loses electrons and iron gains electrons. Iron gains electrons to avoid corrosion and is well protected. This anti-corrosion mechanism is also called cathodic protection, that is, the principle of sacrificial anode protecting the cathode.
       Zinc powder is one of the main anti-rust pigments. Common zinc powder coatings mainly include epoxy zinc-rich primer, inorganic zinc-rich primer and cold galvanized paint. They all use the cathodic protection of zinc to achieve the protection of steel. For the purpose of anticorrosion, this kind of coating is usually used in areas with high requirements for anticorrosion and can better exert its protective effect.

2.  Anticorrosive coating thickness

In order to better guarantee high quality products, we recommend using coating thickness testers. Different products have different requirements for coating thickness. At the same time, it is sprayed by a spray gun or a dish atomizer, and is dispersed into uniform and fine mist droplets by means of pressure or centrifugal force. Then it is applied to the object surface to be coated. This industry uses coating thickness testers more, accounting for a larger proportion of annual sales. In addition, the aluminum profile is used to detect the thickness of the oxide film under the profile. In order to ensure quality and reduce unnecessary waste, relevant regulations require that relevant testing facilities including coating thickness testers must be equipped.
       Many traditional measurement methods on the market are to measure the film thickness of the coating after spray drying. For example, traditional magnetic induction or eddy current coating thickness testers perform contact manual measurement after the coating is dried or dried; the use of a microscope can only measure dry paint films and the cutting process requirements must be very high.
       With the improvement of process technology, the requirements of products are getting higher and higher. The types of supporting film measuring instruments are more and more. When users choose, they need to use different principles according to their principles. (AES), thin film analysis, X-ray fluorescence analysis, magnetic induction analysis and ultrasonic analysis measurement methods. In actual industry and life, it is necessary to select an appropriate coating measurement method from the aspects of whether it accepts destructiveness, the characteristics of the material itself and the accuracy of the measurement according to the actual situation.
       The coating thickness tester makes the anti-corrosion coating technology more advanced. The application fields will be more and more.

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