The study on performances of environment-friendly colorless chemical conversion coatings on aluminum alloy

Abstract

Abstract With the increasingly high requirements on the appearance of electronic equipment and environmental protection, conventional chromate chemical conversion coatings on aluminum alloys gradually showed some shortcomings, such as the color difference in appearance and harm to human health and the environment in the process. In this paper, three kinds of environment-friendly colorless chemical conversion coatings (LANTH-613, ALTRCHR-250, YMT-631) were prepared by using 5056 and 6061 aluminum alloy samples and visually observing the appearance of the coatings. Then, the performances of the coatings, such as the morphology, corrosion resistance, electrical contact resistance, and paint adhesion, were characterized by scanning electron microscope, salt spray test, electrical contact resistance test, and cross-cut test, respectively. As a result, we proposed YMT-631 colorless chemical conversion coating could be used alone as a long-term protective coating for aluminum alloy parts that require the natural appearance of aluminum in electronic equipment, by which corrosion resistance and adaptability in the harsh environment could be significantly improved.