Which stage occurs first when heat is applied to powder coatings?

When heat is applied to powder coatings, the first stage that occurs is the wetting stage. During this stage, the powder particles begin to soften and adhere to the substrate. This is a critical precursor to achieving a smooth and uniform coating. It involves the melting of the powder particles, which allows them to spread across the surface, creating a film that can further undergo the subsequent stages of flow and curing.

The wetting stage is essential for ensuring that the powder can properly cover the substrate, as insufficient wetting can lead to poor adhesion or uneven coverage. After wetting, the flow stage occurs, where the melted powder continues to flow and level out for an optimal finish. The curing stage follows, where cross-linking reactions occur to harden the coating. Understanding this sequence is vital for effective application and achieving the desired performance characteristics of powder coatings.