Konverteringsbeläggning

Konverteringsbeläggning is a surface treatment process used to enhance the properties of metal surfaces. The primary purpose is to create a protective, often thin, layer that improves corrosion resistance, adhesion for subsequent coatings, or provides a specific aesthetic finish. This is achieved through a chemical reaction where the base metal is transformed into a different chemical compound.

Commonly applied to metals like steel, aluminum, zinc, and copper alloys, konverteringsbeläggning is a widely used industrial technique. The process typically involves immersing the metal part in a chemical bath containing specific solutions. The composition of the bath and the immersion time are critical factors determining the type and thickness of the conversion layer.

One of the most well-known types is phosphate conversion coating, which involves reacting the metal surface with phosphoric acid and metal phosphates. This results in a layer of insoluble metal phosphates, offering good adhesion for paint or powder coating. Chromate conversion coatings, traditionally used for aluminum and zinc, provide excellent corrosion resistance and can be colored, though environmental regulations are increasingly restricting their use due to the hexavalent chromium content. For aluminum, anodizing is another form of conversion coating, electrochemically growing a thick, porous oxide layer that can be dyed and sealed.

The benefits of konverteringsbeläggning include improved durability, extended product lifespan, and enhanced performance in various environments. It is a cost-effective method for metal finishing and a crucial step in many manufacturing processes.