Fosfatointina

Fosfatointina, also known as phosphating or phosphate conversion coating, is a chemical surface treatment process used primarily on ferrous metals like steel and iron, and also on aluminum and zinc. The process involves immersing the metal part in an aqueous acidic solution containing metal phosphates, typically zinc, iron, or manganese phosphate. When heated, the acid reacts with the metal surface, causing a thin, crystalline layer of insoluble metal phosphate to form and adhere to the substrate.

This phosphate layer serves several important functions. Firstly, it provides a base for subsequent painting, powder coating, or other organic finishes, significantly improving adhesion and preventing delamination. The crystalline structure of the phosphate coating creates a porous surface that acts as an excellent anchor for paint. Secondly, it offers a degree of corrosion resistance, although it is often used in conjunction with other protective coatings for enhanced performance. Manganese phosphate coatings, in particular, are known for their excellent anti-galling and anti-seize properties, making them ideal for components subjected to friction, such as engine parts and fasteners.

The specific type of phosphate coating used depends on the application. Zinc phosphate coatings are widely used for paint pre-treatment due to their good adhesion and corrosion resistance. Iron phosphate coatings offer a simpler, faster process and are often used when moderate corrosion resistance and paint adhesion are sufficient. Manganese phosphate coatings are chosen for their lubricity and wear resistance. The process typically involves cleaning the metal, followed by the phosphating step, and then rinsing and often a passivation or sealing treatment before the final coating is applied.