What is Yellow Chromatising? Yellow chromatising is a chemical surface treatment primarily for aluminum and aluminum alloys. It forms a protective, corrosion-resistant, yellow-colored chromate layer, improving paint adhesion and corrosion resistance.Yellow chromatising is a chemical surface treatment process used mainly on aluminum and aluminum alloys to improve corrosion resistance and paint adhesion. It creates a thin, protective yellowish chromate conversion coating by chemically reacting with the metal surface. * How It Works: The aluminum surface is treated with a chromate solution (typically containing hexavalent chromium). This creates a thin, porous, corrosion-inhibiting layer of chromium compounds. The coating appears yellow or golden in color, depending on concentration and reaction time. #Yellow Chromatising Manufacturer.