1. Shielding principle: After the coating on the metal surface is dried (cured), the metal surface is separated from the environment. But the coating can not prevent or slow down the corrosion process, because the polymer has a certain water permeability, the average diameter of the pores in its structure is 10-5 ~ 10-7cm, and the diameter of water and oxygen molecules is usually only 10-6 ~ 10-8cm. In order to improve the impermeability of the coating, the coating should use a film-forming substance with little air permeability and a solid filler with large shielding property, so that the coating reaches a certain thickness and is uniform, dense and non-porous. 2. Principle of corrosion inhibition: Phosphating film plays the main role of protection and corrosion inhibition. Secondly, the internal components of the paint (such as red pigment, zinc chrome yellow and other pigments with corrosion resistance) react with the metal to passivate the metal surface or generate a protective substance to improve the protective effect of the coating. In addition, some oils produce degradation products under the drying effect of metal soap, which can also play the role of organic corrosion inhibitor. 3. The principle of electrochemical protection: When the medium penetration coating contacts the metal surface, it will form electrochemical corrosion under the film. Use a relatively active metal as a filler (such as zinc) in the paint, which plays the role of sacrificial anode protection, and the corrosion products of zinc are salt-based ZnCl2, ZnCO3, etc., which fills the gaps in the coating, making The coating is more dense, which greatly reduces corrosion. Dinosaur Island Toys Shantou Chenghai Sweet Baby Toys Firm , https://www.sweetbabytoys.com