Have you chosen the right water-based anti-corrosion coating for steel structures?

In recent years, with increasingly stringent environmental policies, water-based rust-proof coatings for steel structures have seen significant development and are now widely applied across numerous fields.

Water-based anti-corrosion coating systems for steel structures, particularly those cured at ambient temperatures—such as water-based epoxy and acrylic coatings—remain predominantly emulsion-based. These multi-phase systems exhibit heightened sensitivity to oil contamination on substrates and inferior penetration compared to solvent-based paints. Their film density and barrier properties still fall short of solvent-based alternatives. If the rust-preventive primer is of poor quality and fails to effectively inhibit rust spread, the topcoat—due to its lower film density compared to oil-based paints—struggles to fully block moisture and salt penetration. This accelerates substrate corrosion, leading to rust recurrence within the coating system and film failure. 

For light-duty corrosion protection, selecting the appropriate rust-inhibiting primer is equally critical. In the current steel structure corrosion protection field, rust conversion primers and rust-inclusive primers are predominantly used. Both primarily function to prevent rust—either by completely passivating rust or by penetrating, encapsulating, and shielding rust to achieve true rust inhibition. These primers are then paired with compatible intermediate and topcoats to maximize the corrosion protection lifespan of the coating system.

However, rust conversion primers and rust-inclusive primers on the market vary significantly in quality and price, with limited application case histories. Consequently, customers often struggle to assess the relative merits of primers recommended by different manufacturers. This requires extensive validation and practical experience, a process inevitably fraught with challenges.

Our R&D engineers have developed rust converters like N560, N680, CP05, and CP11 to accommodate diverse application scenarios. We've observed a common issue during client consultations: many customers fixate on price upfront, considering only options below a predetermined threshold. It's important to recognize that prices below a certain level often exclude many qualified water-based primers, increasing the likelihood of quality issues. Here, we recommend that users prioritize evaluating the rust prevention performance of water-based primers to identify products that meet their requirements. Only then should they compare prices or cost-effectiveness across different products and make informed purchasing decisions.