How to prevent flash rusting in anti-rust paint?

What is flash rust?

1. When water-based coatings are applied directly to metal substrates, the high latent heat of water evaporation causes water to remain on the metal surface for an extended period, leading to corrosion of the metal substrate. This phenomenon is termed ‘flash rust’.
2. Flash rust typically occurs within minutes of application, before the coating has fully cured.

Three Key Factors Contributing to Flash Rust

Moisture, metal, oxygen
Flash rust is an electrochemical phenomenon. Areas with potential differences create pathways for charge migration, leading to corrosion under the combined influence of water and oxygen.

Key Measures to Effectively Prevent Flash Rust in Anti-Rust Paints

1. Accelerate drying
2. Increase the coating's pH value
3. Incorporate corrosion-inhibiting pigments such as zinc phosphate and aluminium phosphate
4. Select appropriate anti-flash rust agents
5. Choose high-quality resin systems

Water Resistance Test

Prepare test panels, allow natural drying for 12 hours, then immerse in water for 240 hours. Observe for blistering, peeling, rust formation, or cracking.

Adhesion Testing

Formulate waterborne epoxy with an equal volume of anti-flash rust agent.
Cure panels for 12 hours, then test using cross-hatch adhesion method.

Storage Stability Comparison at 70°C

Evaluate anti-flash rust agent and curing agent stability.
500-hour Salt Spray Test Comparison