Fosfaatiseerimine

Fosfaatiseerimine, also known as phosphating, is a surface treatment process used to improve the corrosion resistance and adhesion of paint and other coatings on metal surfaces, primarily ferrous metals like steel and iron, as well as aluminum and zinc. It involves immersing the metal part in a phosphating solution, typically containing phosphoric acid and metal phosphates, at an elevated temperature. This chemical reaction causes a thin, adherent layer of insoluble metal phosphate crystals to form on the metal surface.

The resulting phosphate conversion coating is typically amorphous or crystalline, and its composition depends on the specific phosphating chemicals used. Common types include zinc phosphate, iron phosphate, and manganese phosphate. Zinc phosphate coatings are widely used for their excellent corrosion resistance and paint adhesion properties, making them ideal for automotive parts and appliances. Iron phosphate coatings offer good paint adhesion and are often used for interior applications where extreme corrosion resistance is not required. Manganese phosphate coatings provide excellent lubricity and wear resistance, commonly applied to engine components and firearms.

The phosphating process typically involves several stages: cleaning and degreasing the metal surface to remove contaminants, followed by the phosphating bath itself. After phosphating, the parts are rinsed and often treated with a passivating agent to further enhance corrosion protection and prepare the surface for subsequent coating. The thickness and properties of the phosphate coating can be controlled by adjusting parameters such as immersion time, temperature, and solution concentration. Fosfaatiseerimine is a cost-effective and versatile pre-treatment method widely employed across various industries.