(1) Organic zinc-rich coatings: Epoxy resin, chlorinated rubber, vinyl resin and polyurethane resin are commonly used as film-forming binders for organic zinc-rich coatings. The most commonly used is epoxy zinc-rich paint, among which polyamide cured epoxy zinc-rich primer is the most widely used among organic zinc-rich primers. Organic film-forming materials of organic zinc-rich coatings have poor conductivity, so it is necessary to increase the content of zinc powder to ensure conductivity. SSPC Coating -20 of American Steel Structure Painting Association stipulates that zinc powder of organic zinc-rich coating accounts for not less than 77% of dry film mass, and zinc powder of inorganic zinc-rich coating accounts for not less than 74% of dry film mass, in order to increase the conductivity of coating film. In addition, the cohesiveness of organic resin is better than that of inorganic resin, which also provides a better guarantee for the adhesion of high-content zinc powder. The organic type is slightly worse than the inorganic type in rust prevention performance, and worse than the inorganic type in conductivity, heat resistance and solvent resistance, but it has good construction performance and great tolerance for steel surface treatment quality. At the same time, the epoxy zinc-rich primer is compatible with most coatings, and there is a synergistic effect between the matching coatings, which makes the service life of the matching coatings increase by 1.5-2.4 times compared with that when used alone. Cold-coated zinc coating is a new coating variety in recent years, which is mainly used to replace hot dip galvanizing or in the case of difficult construction of hot dip galvanizing. It consists of zinc powder, organic resin and solvent. So it should be divided into organic zinc-rich coatings. This coating is characterized by high zinc powder content to achieve good anticorrosion effect.

(2) Inorganic zinc-rich coatings: Inorganic zinc-rich coatings can be divided into solvent-based and water-based. Solvent-based inorganic zinc-rich coatings are based on ethyl orthosilicate, because ethyl orthosilicate can be dissolved in organic solvents. After spraying, the alkoxy group in TEOS absorbs moisture in the air while the solvent volatilizes, and then undergoes hydrolysis reaction, cross-linking and curing to form high molecular siloxane polymer. That is, the process of hydrolysis and polycondensation of ethyl silicate to form a network polymer coating. Waterborne inorganic zinc-rich coating is a two-component coating composed of waterborne inorganic silicate (sodium, potassium and lithium) resin, zinc powder and additives. At present, phosphate zinc-rich coatings have been developed, and waterborne inorganic zinc-rich coatings have been developed for more than 50 years. This product was first developed by NASA, and is used for rust prevention of satellite receiving stations in Pacific islands. Waterborne inorganic zinc-rich coatings can be divided into post-curing type and self-curing type. After the coating film of post-curing inorganic zinc-rich coating is dried, it needs to be heated or coated with acidic curing agent (dilute phosphoric acid or MgCl2 aqueous solution), which is complicated in construction and fragile in coating film. At present, water-based self-curing inorganic zinc-rich coatings are widely used in the market.