sinkkifosfatointi

Sinkkifosfatointi is a surface treatment process used to improve the corrosion resistance and paint adhesion of metal surfaces, primarily steel and aluminum. The process involves immersing the metal part in a phosphoric acid solution containing zinc ions and other additives. During the reaction, a thin, insoluble layer of zinc phosphate crystals forms on the metal surface. This crystalline layer is amorphous and porous, providing a good base for subsequent coating operations.

The thickness and structure of the phosphate layer can be controlled by adjusting parameters such as bath temperature, concentration, and immersion time. Different types of zinc phosphate coatings exist, varying in crystal size and density, each suited for specific applications. For example, fine-grained coatings are often preferred for automotive applications where a smooth finish is desired, while coarser coatings might be used for heavy industrial equipment.

Beyond its primary functions of corrosion protection and paint adhesion, zinc phosphating also offers some degree of wear resistance. It is a widely used pretreatment in various industries, including automotive manufacturing, appliance production, and general metal fabrication, preparing surfaces for painting, powder coating, or other organic finishes. The process is cost-effective and has been a staple in metal finishing for decades.