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Epoxy zinc-rich primers are an excellent anti-corrosion and rust-prevention coating for steel structures. They not only improve the adhesion of paint to the substrate as well as the cohesion of the paint film, but also increase the cross-linking density of the film, thereby enhancing the coating’s resistance to salt spray corrosion. Zinc-rich primers offer significant benefits in applications related to steel structures, and they also demonstrate excellent anti-corrosion properties in various other fields. Today, we will focus on the anti-corrosion applications of zinc-rich primers in railway bridges. Can epoxy zinc-rich primers meet the technical requirements for the corrosion protection of steel, as well as the corrosion resistance demands of bridges used on high-speed railways? Let’s first understand what the specific types of corrosion in steel structure bridges are Type 1: Uniform corrosion. Uniform corrosion is the most common form of corrosion; its main characteristic is that the corrosion occurs across the entire metal surface, causing the overall thickness of the metal to decrease at a constant rate. Although uniform corrosion causes significant metal loss, it is not particularly dangerous. Since the rate of corrosion is consistent, it can be easily predicted and prevented. With proper engineering design and appropriate anti-corrosion measures, steel bridges generally do not suffer from sudden corrosion incidents. Type II: Pitting corrosion – In a suitable environmental medium, after a certain period of time, most of the surface of the steel remains uncorroded. However, in individual points or micro-regions, pits or pockmarks appear due to selective corrosion of the metal. Over time, these pits deepen, and this form of corrosion is known as pitting corrosion. Pitting generally occurs due to the adsorption of chloride ions in certain defects of the metal surface film. Type 3: Crevice corrosion. Crevice corrosion is a form of local corrosion that occurs when there are gaps at the surface where metals meet each other or where a metal meets a non-metal, in the presence of corrosive agents. It mainly occurs in areas such as metal rivets, bolt connections, screw joints, and between non-metallic gasket materials and metal materials. The application of epoxy zinc-rich primers provides excellent salt spray resistance and corrosion protection, making it an essential safeguard for high-speed rail, railway, and bridge facilities that require long-term corrosion and rust prevention. It is able to achieve such remarkable performance because when the PVC value of its paint film is 42% and the zinc powder content in the dry paint film is 82%, it improves the adhesion of the paint to the substrate as well as the cohesion of the paint film, increases the cross-linking density of the film, and thereby greatly enhances the salt spray resistance of the coating. Its excellent corrosion resistance also makes it one of the essential primers for steel structure buildings. Since no single anti-corrosion paint can simultaneously provide shielding, UV protection, and cathodic protection for steel, the anti-corrosion coating of steel structural bridges requires a combined effect from primers, intermediate coats, and topcoats that are resistant to corrosion and weathering, as well as easy to apply.