Foszfátolás

Foszfátolás, also known as phosphating, is a metal surface treatment process used to improve corrosion resistance and prepare metal surfaces for painting or coating. It involves immersing the metal part in a phosphoric acid solution containing metal phosphates. The acid reacts with the metal surface, creating a thin, crystalline layer of insoluble metal phosphates. This layer is typically iron phosphate, zinc phosphate, or manganese phosphate, depending on the specific process and desired properties.

The phosphating process begins with cleaning the metal surface to remove any grease, oil, or rust. This is followed by a rinsing step. Then, the metal part is immersed in the phosphating bath, which is usually heated. The duration of immersion varies depending on the type of metal and the desired coating thickness. After phosphating, the part is rinsed again to remove any residual chemicals and then dried. Sometimes, a passivation or sealing treatment is applied after phosphating to further enhance corrosion resistance.

The primary benefits of foszfátolás include enhanced adhesion for subsequent coatings like paint, powder coating, or electroplating, as the porous phosphate layer provides a better mechanical key. It also significantly improves the corrosion resistance of the underlying metal by providing a barrier and by passivating the surface. Different types of phosphate coatings offer varying levels of protection and frictional properties, making foszfátolás a versatile pre-treatment in automotive, appliance, and general manufacturing industries.