01 Epoxy Anticorrosive Coatings
Epoxy anticorrosive coatings are widely used for the protection of both the inner and outer walls of pipelines. They offer strong adhesion, resistance to acids and alkalis, and low shrinkage. However, the disadvantages include susceptibility to powdering and poor weather resistance. Particularly if curing is inadequate, the coating can have poor water resistance, causing it to turn white and become brittle.
02 Asphalt Anticorrosive Coatings
Asphalt coatings are made from readily available and inexpensive raw materials. They resist corrosion by dilute acids and alkalis at room temperature, dry quickly, and possess good elasticity. Often used as a waterproof layer, asphalt coatings contain hydrocarbon structures, which can dissolve in some organic solvents and decompose under strong oxidant conditions. They are not resistant to organic solvents and can become brittle at low temperatures. Existing products like coal tar epoxy, coal tar enamel, and petroleum asphalt paint are modified asphalt paints designed to enhance hardness, temperature resistance, weather resistance, and adhesion. The primary use of asphalt coatings is for waterproofing and anticorrosion of underground pipelines. When used for underground pipeline anticorrosion, they are typically combined with a glass cloth coating.
03 Urushiol Anti-Corrosion Coating
Urushiol coating is made by dehydrating and condensing raw lacquer and then diluting it with organic solvents. Compared to raw lacquer, it is less toxic and dries faster. Urushiol coating is resistant to acids, alkalis, ammonia, and water. It can be used as an anti-corrosion coating for substances like ammonia, ammonia water, chlorine, and hydrogen sulfide gas, as well as for moisture-proofing and protecting underground pipelines.
04 Polyurethane Anti-Corrosion Coating
Polyurethane coatings are resistant to acids, alkalis, oils, water, and wear. They are available in single-component moisture-curing types, two-component catalyst-curing types, and hydroxyl-curing types. To improve certain properties, polyurethane coatings are often mixed with epoxy resin, asphalt, and other materials. Homemade polyurethane asphalt paint features a fast-curing film and good water resistance. It is suitable for the inner walls of pressure water pipes in power stations and the inner walls of underground steel pipes in oil field injection wells.
05 Olefin Resin Anticorrosion Coating
Olefin resin anticorrosion coatings are primarily made from resins containing ethylene or propylene molecular structures, along with modified resins, fillers, etc. They offer good water resistance, acid resistance, alkali resistance, and weather resistance.
06 Perchloroethylene Resin Anticorrosion Coating
Perchloroethylene coatings are widely used in chemical pipelines to prevent atmospheric corrosion. However, they have poor adhesion to pipelines. To improve adhesion, epoxy resin modifications are often employed with some success.
07 Chlorinated Rubber Anticorrosion Coating
Chlorinated rubber, obtained by chlorinating natural or synthetic rubber, is dissolved in an organic solvent to create chlorinated rubber coatings. These coatings resist corrosion by dilute acids and alkalis, have good permeability resistance, and are flame retardant. They are generally used for atmospheric corrosion protection and are effective in this role.
08 High-Temperature Anticorrosion Coating
High-temperature anticorrosion coatings are mainly silicone resin-based and can withstand temperatures up to 500°C. They offer good water resistance, corrosion resistance, and weather resistance. However, they have poor adhesion, are expensive, and products containing lead powder require drying.
09 Zinc-Rich Anti-Corrosion Coating
Zinc-rich coatings are categorized into inorganic and organic types. Inorganic coatings consist of zinc powder, sodium silicate (water glass), and curing agents, while organic coatings are made of zinc powder and resin (mainly epoxy resin). The anticorrosion principle of zinc-rich coatings is that zinc powder provides cathodic protection to steel materials, making them suitable for use in water, seawater, oil, and marine atmospheres. They are not suitable for acidic or alkaline media.
