How to Address Flash Rust in Water-Based Industrial Coatings?

As the industrial economy continues to develop, it inevitably brings about significant losses, with corrosion accounting for a large portion. Typically, the protection of our equipment relies on coating systems. However, industrial coatings contain substantial amounts of solvents, and solvent evaporation can pollute the environment. With the continuous refinement of environmental policies, water-based coatings have been evolving to meet VOC emission standards. Yet, challenges arise during this development process.

Over the next two installments, Enze Chemical will thoroughly discuss common issues encountered during the application of water-based industrial coatings, their causes, and corresponding solutions.

Paint Film Issue—Flash Rust

Flash rust, also known as flash corrosion, occurs when water in the coating comes into contact with metal surfaces (e.g., iron, nail heads, steel). This phenomenon is more likely to occur during application in humid climates and primarily affects corroded or recently activated metal surfaces.

Causes of Flash Rust：
1. Inadequate pretreatment, leaving rust, surface rust, or metal scale on the metal workpiece;
2. Application in low-temperature, high-humidity conditions, or excessive coating thickness, slowing water evaporation and ultimately delaying film drying, leading to flash rust;
3. Potentially related to the dissolution and precipitation of iron compounds. Prolonged contact time between water and the metal substrate in low-temperature, high-humidity environments facilitates flash rust (rusting);
4. Defects in the formulation of the water-based industrial coating product itself.