Flash Rust Inhibitors for Water-Based Coatings

With the successive introduction of national environmental protection policies and measures, water-based eco-friendly coatings have been widely adopted in rust and corrosion prevention projects across various industries. The extensive use of water-based coatings has frequently caused “flash rust” issues on paint films, posing challenges for construction clients and partially compromising the protection of metal substrates.

Prolonged contact between moisture in wet paint films and steel, coupled with oxygen exposure, increases the likelihood of flash rust occurrence. Flash rust inhibitors are primarily used in metal coatings to prevent this issue. Certain wood finishes may also be temporarily applied to metal substrates, necessitating the addition of flash rust inhibitors in such cases.

Since water-based coatings are conductive, charge migration pathways form between different areas. Consequently, corrosion occurs rapidly during the film-forming process of water-based coatings, resulting in flash rust. Clearly, the longer the wet film persists, the more severe the flash rust becomes—explaining why low temperatures and high humidity exacerbate the phenomenon.

While electrochemical reactions underlie flash rust, its occurrence during water-based coating application involves highly complex conditions. Beyond substrate variations, factors like coating pH, environmental temperature/humidity, wind speed, and film thickness all influence flash rust development.

So how can flash rust be resolved? After 19 years of research analyzing the causes of “flash rust,” our company discovered that the most direct solution for rust-preventive paint flash rust issues is to use flash rusr inhibitors. This completely suppresses flash rust. Our anti-flash rust inhibitor CK34 demonstrates excellent anti-flash rust performance on welds and cast iron components, particularly in low-temperature, high-humidity environments. Adding just 1% can resolve flash rust problems.