chromátování

Chromátování, also known as chromate conversion coating, is a chemical process used to provide corrosion resistance, improve paint adhesion, and enhance the appearance of various metal surfaces. Primarily applied to aluminum, zinc, cadmium, magnesium, and their alloys, chromátování forms a protective layer through a chemical reaction between the metal substrate and a chromate-based solution.

The process involves immersing the metal part in a bath containing chromic acid or chromate salts, along with other additives, under specific temperature and time conditions. This reaction creates a thin, passive film that is integral to the metal surface. The resulting coating is typically transparent, iridescent, or colored, depending on the specific chromate formulation and the metal being treated. Different types of chromate conversion coatings exist, including hexavalent chromium and trivalent chromium processes, with the latter being increasingly adopted due to environmental and health regulations regarding hexavalent chromium.

Chromátování is widely used in industries such as aerospace, automotive, electronics, and construction. For example, it protects aircraft components from corrosion in harsh environments and provides a base for painting on automotive parts. The coating's effectiveness lies in its ability to self-heal minor scratches, further extending the lifespan of the protected metal. While effective, proper waste treatment is essential due to the chemicals involved.