What is the function of metal surface painting?

Metal surface painting is a method to prevent metal oxidation and corrosion. Corrosion around us refers to the damage, performance degradation or state deterioration of various materials under the action of the environment. Metal surface coating is an important means to prevent metal corrosion. A good paint protective layer can be used as a barrier to prevent the invasion of corrosive media.

importance

Because corrosion is an irreversible spontaneous process, even high-quality coatings are difficult to protect metals from corrosion. Especially when the paint coating on the metal surface is poorly combined, damaged, or has defects such as pinholes, blisters, cracks and falling off, the protection effect of the paint coating will be greatly reduced, and even lead to the intensification of metal corrosion. Therefore, it is necessary to analyze the corrosion factors of painting and take effective measures to prevent it.

Corrosion mechanism of metal in painting

Generally speaking, the corrosion of metals is the result of the joint action of many factors, one of which plays an important role in the corrosion process. The coating protective layer is formed by spraying on the metal surface. The corrosion area of the metal is located in the interface area between the coating film and the metal surface, and continues to erode and expand to the depth of the metal substrate.

If the spraying coating on the metal surface can effectively isolate the penetration of water, oxygen, electrons and stray ions, the corrosion of the sprayed metal can be greatly slowed down or avoided. If the isolation effect is not good, the anti-corrosion and anti-corrosion protection effect of the coating maintenance layer on the metal is not good. The production practice shows that the water permeability of the paint protective layer seriously affects the adhesion of the metal paint surface, while the air permeability seriously affects the corrosion performance of the metal. There are many forms of corrosion of coated metals, but the root cause of corrosion is closely related to chemical and electrochemical effects.