The direct economic loss caused by metal corrosion is about trillion dollars annually in the world. In some industrially developed countries, the loss of metal corrosion even accounts for more than 5% of the annual GNP, which is greater than the total economic loss caused by various natural disasters. Metal corrosion is a major economic problem. Its main harm is not only the loss of metal itself but more serious is the loss caused by the structural damage of metal products than the loss of metal itself.
Types of metal antiseptic coating
In fact, the damage caused by metal corrosion can be avoided or mitigated by some appropriate anti-corrosion measures. There are four main methods to prevent metal corrosion.
- First, improve the corrosion resistance of metal materials. In the process of manufacturing metal parts, corrosion resistant materials such as chromium and nickel, which are difficult to react with the surrounding medium, are added to alter the metallographic structure of the metal.
- The second is to use the coating method corrosion, and the coating process includes coating and spraying, coating and chemical conversion coating.
- Third, the corrosive medium can be treated, but this method can only be carried out under the condition of the limited number of the corrosive medium. Of course, the atmosphere full of space cannot be treated.
- The fourth is electrochemical protection. When an electrolyte is present on the surface of a metal, the protective metal potential is changed with direct current, and the act of slowing or stopping corrosion is called electrochemical protection.
According to the composition, anti-corrosion coating can be divided into the following four categories: organic coating, mainly oil asphalt, epoxy powder, baking tar enamel, sintered epoxy powder (FBE) and three layers of polyethylene (three layers PE) and polyurethane; Inorganic coating, mainly enamel coating, glass coating and ceramic coating; Corrosion-resistant metal coatings (nickel, chromium, zinc and other metal corrosion-resistant coatings); composite corrosion-resistant coatings.
Ceramic coating has been widely paid attention to and studied for its high chemical stability, corrosion resistance, oxidation resistance, and high-temperature resistance. With the development of aerospace, electronics, military, and other advanced science and technology, the application of ceramic coating has been growing at a high speed for nearly half a century.
Ceramic coating is a new type of environmental protection coating, with high hardness, low harmful gas release, good anti-cathode peeling ability, chemical resistance, corrosion resistance, self-cleaning and anti-aging characteristics.
Nano ceramic coating
Compared with the ordinary ceramic coating, the grain of nanoceramics coating is more refined and evenly dispersed, and the number of grain boundary increases greatly, which makes the hardness, toughness, wear resistance, bonding strength, corrosion resistance and density of nanoceramics coating significantly improved. It can not only improve the service life of ceramic materials but also make ceramic coating applied in more fields.
At present, the main anti-corrosion coating ingredients include nano alumina, nano zirconia, nano titanium oxide, and nano silicon oxide. The coating formula should be formulated according to different application conditions.
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