Poedercoatings

Powder coatings are a type of coating material composed of finely ground particles of resin, pigments, fillers and additives that are applied as a free-flowing powder and then fused to a surface by heating. The powder is typically applied to electrically grounded parts by electrostatic spray or by immersion in a fluidized bed. After application, the part is heated in an oven, causing the powder to melt and chemically crosslink into a durable, solid film. The process allows the coating to achieve relatively uniform film thickness without the use of solvents.

Resins used in powder coatings are mainly thermosetting, with common families including epoxy, polyester, epoxy–polyester hybrids and polyurethane, as well as fluoropolymers for specialty finishes. Thermoplastic powders are also available but are less widely used due to higher processing temperatures required for fusion. Typical finishes offer good wear resistance, corrosion protection, weatherability and color stability. Gloss, texture and color can be tailored for architectural, automotive, appliance and consumer goods industries.

Surface preparation is important and usually includes degreasing and some form of pretreatment to improve adhesion, such as phosphate coating for steel or pretreatments for aluminum. Substrates are most often metals; plastics and other materials may require primers or specialized powder formulations. Complex geometries can present challenges for complete coverage, and recessed areas may trap powder without adequate design or masking.

Advantages of powder coatings include low solvent emissions, high material efficiency due to overspray reclaim, strong corrosion and chemical resistance, and the ability to apply thicker coatings with controlled finish. Limitations include equipment costs, and the need for electrical grounding and adequate curing ovens. Powder coatings are widely used in automotive, architectural, appliance and industrial applications.