Aluminum alloy profiles and chromate conversion coating

Before the substrate is sprayed, the aluminum alloy profile enters into the coating workshop by the previous process—pretreatment, and its surface has oil, oxide, aluminum swarf and other acrobatics and must be removed, otherwise the coating will form obvious particles and pits, which will seriously Affects the adhesion and appearance quality of fluorocarbon coatings.

When the surface of the profile is treated with a chromate conversion film process, a certain thickness and certain appearance quality requirements must be met (see the table below. The processing time is strict, the time is too short, and the formation of the chromated film layer is not perfect, which is not conducive to If the coating is too long (excessive reaction), it will form a powdery substance, causing pinholes, orange peels, etc. The general control conversion film thickness is in the range of 200 to 1300 mg/m2 (measured by gravimetric method). The corrosion resistance of the film is better, and its salt spray corrosion resistance test result is almost twice that of the phosphoric acid chromic acid film, and it can even pass the neutral salt spray corrosion test of 2000 hours. One of the reasons for its superior corrosion resistance is chrome plating. Six prices remain in the film and play a role in repairing the corrosive medium.