Principles of anti-corrosion coatings

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Anti-corrosion coatings are generally divided into conventional anti-corrosion coatings and heavy-duty anti-corrosion coatings, which is an indispensable coating in paint coatings. Conventional anti-corrosion coatings play a role in preventing corrosion of metals under general conditions and protect the service life of non-ferrous metals; heavy-duty anti-corrosion coatings are compared to conventional anti-corrosion coatings, which can be applied in relatively harsh corrosive environments and have the ability to A type of anti-corrosion coating that achieves a longer protection period than conventional anti-corrosion coatings. The anti-corrosion principle of general anti-corrosion coatings lies in the direction of chemistry, physics and electrochemistry. The following is a detailed explanation:
1. The chemical principle of anti-corrosion
The chemical principle of anti-corrosion is to neutralize harmful acid-base substances into neutral and harmless substances to protect the materials in the anti-corrosion coating from corrosive substances. Some amphoteric compounds, such as aluminum hydroxide, barium hydroxide and zinc oxide, are often added to anti-rust coatings. These substances can easily react with acid and alkali harmful substances to achieve anti-corrosion effects.

2. The physical principle of anti-corrosion
The physical principle of anti-corrosion is to isolate the protected material from external corrosive substances with an anti-corrosion coating. The physical principle of anti-rust paint is to use a film-forming agent to obtain a dense anti-corrosion coating to isolate the damage of the anti-corrosion effect on the protected material. For example, lead-containing paint and oil can form lead soap to ensure the anti-corrosion coating The density.

3. The electrochemical effect of anti-corrosion
The electrochemical effect of anti-corrosion refers to the addition of some special substances to the anti-rust paint, so that when moisture and oxygen pass through the anti-rust paint, they will react to form anti-corrosion ions, passivating the surface of metals such as steel, and thereby prevent metal ions. Dissolution, to achieve the purpose of anti-corrosion, the most common of this special substance is chromate.

The application areas of anti-corrosion coatings mainly include the following five aspects:
①Emerging offshore engineering: offshore installations, coastal and bay structures, offshore oil drilling platforms;
②Modern transportation: highway guardrails, bridges, boats, containers, trains and railway facilities, automobiles, airport facilities;
③Energy industry: hydraulic equipment, water tanks, gas tanks, petroleum refining equipment, petroleum storage equipment (oil pipes, oil tanks), power transmission and transformation equipment, nuclear power, coal mines;
④Large industrial enterprises: papermaking equipment, medical equipment, food and chemical equipment, inner and outer walls of metal containers, pipelines, storage tanks of chemical, steel, petrochemical plants, mining and smelting, cement plant equipment, floors, walls, and cement components with corrosive media;
⑤Municipal facilities: gas pipelines and their facilities (such as gas tanks), natural gas pipelines, drinking water facilities, garbage disposal equipment, etc.

Post time: Dec-07-2021