fosfatisering

Fosfatisering, also known as phosphating, is a surface treatment process that creates a protective layer of crystalline phosphate on a metal surface. This is typically applied to iron, steel, zinc, and aluminum. The primary purpose of phosphating is to enhance corrosion resistance and to provide a good base for subsequent coatings such as paint, powder coating, or oil.

The process involves immersing the metal part in a heated acidic solution containing phosphoric acid and metal phosphates. Chemical reactions occur, causing the metal surface to be converted into a thin layer of insoluble metal phosphates. The specific type of phosphate used—iron phosphate, zinc phosphate, or manganese phosphate—determines the characteristics of the resulting coating. Iron phosphate coatings are generally thinner and provide less corrosion resistance but are excellent for paint adhesion. Zinc phosphate coatings are thicker and offer superior corrosion protection and lubrication properties. Manganese phosphate is often used for wear resistance, particularly on moving parts.

Fosfatisering is a crucial step in many manufacturing processes, especially in the automotive and appliance industries. It improves the durability and longevity of metal components by preventing rust and ensuring better adhesion of decorative and protective finishes. The process is environmentally controlled, with wastewater treatment being a significant consideration.