浙江Hexavalent chromium (immersion) - aluminum doors and windows

In the production process of aluminum doors and windows, hexavalent chromium (immersion) treatment is a surface treatment process, which is mainly used to enhance the corrosion resistance, wear resistance and decorative properties of aluminum doors and windows. The following is a detailed introduction about it:

principle

Hexavalent chromium compounds are highly oxidizing. When aluminum doors and windows are immersed in a solution containing hexavalent chromium, hexavalent chromium will react chemically with aluminum to form a chromate conversion film on the aluminum surface. This film can prevent aluminum from contacting with external air, moisture and other corrosive substances, thereby protecting aluminum doors and windows.

Process

Pretreatment: Before the hexavalent chromium immersion treatment, the aluminum doors and windows need to be pretreated, including cleaning, degreasing, pickling and other steps to remove impurities such as oil, dust and oxide scale on the surface, ensure that the aluminum surface can fully contact with the hexavalent chromium solution, and improve the quality of the conversion film.

Soaking treatment: Soak the pretreated aluminum doors and windows in a solution containing hexavalent chromium. The concentration, temperature and soaking time of the solution will be adjusted according to the material, shape and use requirements of the aluminum doors and windows. Generally speaking, the soaking time ranges from a few minutes to tens of minutes. During the soaking process, the solution needs to be stirred continuously to ensure the uniformity of the solution and the adequacy of the reaction.

Post-treatment: After soaking, take the aluminum doors and windows out of the solution and rinse them with clean water to remove the residual hexavalent chromium solution and reaction products on the surface. Then dry them, usually by hot air drying or natural drying, to solidify the chromate conversion film on the aluminum surface and improve its hardness and corrosion resistance.

advantage

Good corrosion resistance: The hexavalent chromium conversion film has excellent corrosion resistance, which can effectively prevent aluminum doors and windows from being corroded during long-term use and extend their service life.

Higher hardness and wear resistance: The conversion film has a higher hardness, which can improve the wear resistance of the surface of aluminum doors and windows, making it less susceptible to scratches and wear, and maintaining a good appearance.

Good decorative effect: The hexavalent chromium conversion film can present different colors, such as golden yellow, rainbow color, etc. It has good decorative effect and can meet the requirements of different users for the appearance of aluminum doors and windows.

Simple process: The hexavalent chromium immersion treatment process is relatively simple, with low equipment investment and low production cost, making it suitable for large-scale industrial production.