EFFECT OF MULTI-STEP ANODIZING METHODS ON THE OPTICAL ABSORPTION OF BLACK COATINGS ON 2024 ALUMINUM ALLOY

Authors

Department of Nanotechnology, Faculty of Chemistry, University of Isfahan, 8174673441, Isfahan, Iran

Abstract

 Development of materials with the ideal black body absorption spectrum are of great interest. Such materials could improve the efficiency of solar cells, and passive cooling and heat transfer systems as well as the protective and decorative coatings. Fabricating black anodizing coatings is promising for this purpose because they exhibit low light reflection from the surface. Such coatings can be produced through successive anodizing and black coating of aluminum alloys. In this study, the effect of anodizing repetition on the absorption coefficient of the black anodizing coatings on 2024 aluminum alloy was investigated, as model. All the parameters were fixed in the black coloring stage to evaluate the influence of the anodizing steps. After a one-step anodizing, the black coatings showed an absorption coefficient of 0.956 in the visible region and 0.911 in the of 220 to 2200 nm wavelength range, while their absorption coefficient increased after a three-step anodizing up to 0.982 in the visible region and up to 0.966 in the 220 to 2200 nm wavelength range. This indicates that anodizing repetition helps the optical absorption of black anodizing coatings to approach the optical absorption of an ideal black body.

Keywords


1. Chattopadhyay, S., Huang, Y.F., Jen, Y.J., Ganguly, A., Chen, K.H. and Chen, L.C., "Anti-Reflecting and Photonic Nanostructures", Materials Science and Engineering: R: Reports, Vol. 69, No. 1-3, pp. 1-35, 2010.
2. Mondolfo, Lucio F., Aluminum alloys: structure and properties, London; Butterworths, 1976.
3. Garcia-Vergara, S., Skeldon, P., Thompson, G., Habakaki, H., "Tracer Studies of Anodic Films Formed on Aluminium in Malonic and Oxalic Acids", Applied Surface Science, Vol. 254, No. 5, pp. 1534-1542, 2007 .
4. Abd El-Hameed, A.M., Abdel-Aziz, Y.A. and El-Tokhy, F.S., "Anodic Coating Characteristics of Different Aluminum Alloys for Spacecraft Materials Applications", Materials Sciences and Applications, Vol. 8, No. 2, pp. 197-208, 2017.
5. Uma Rani, R., Sharma, A.K., Mayanna, S.M., Bhojraj, H. and Bhandari, D.R, "Surface Engineering for Thermal Control of Spacecraft", Surface engineering, Vol. 21, No. 3, pp. 249-253, 2005.
6. Goueffon, Y., Arurault, L., Mabru, C., Tonon, C. and Guigue, P., "Black Anodic Coatings for Space Applications: Study of the Process Parameters, Characteristics and Mechanical Properties", Journal of Materials Processing Technology, Vol. 209, No. 11, pp. 5145-5151, 2009.
7. Masuda, H., Fukuda, K., "Ordered Metal Nanohole Arrays Made by a Two-Step Replication of Honeycomb Structures of Anodic Alumina", science,Vol. 268, No. 5216, pp. 1466-1468, 1995.
8. Kumar, S., Malhotra, L., Chopra, K., "Nickel Pigmented Anodized Aluminium as Solar Selective Absorbers", Solar energy materials,Vol. 7, No. 4, pp. 439-452, 1983.
9. Goueffon, Y., Arurault, L., Fontorbes, S., Mabru, C., Tonon, C. and Guigue, P., "Chemical Characteristics, Mechanical and Thermo-Optical properties of Black Anodic Films Prepared on 7175 Aluminium Alloy for Space Applications", Materials Chemistry and Physics, Vol. 120, No. 2-3, pp. 636-642, 2010.
10. Zhang, Z., Collins, M., Lau, E., Botting, C., Bahrami, M., "The Role of Anodization in Naturally Cooled Heat Sinks for Power Electronic Devices", Journal of Heat Transfer, Vol. 142, No. 5, pp. 052901, 2020.
11. ESA ECSSQ7003 A, Blackanodizing of Metals with Inorganic Dyes, http://www.ecss.nl (update of the PSS01703) April 2006.
12. Sharma, A.K., Bhojaraj, H., Narayanamurthy, H. and MOHIDEEN, J., "Integral Black Anodizing on Aluminium Alloys", Journal of Spacecraft Technology, Vol. 2, No. 2, pp. 35-43, 1992.
13. Zaraska, L., Sulka, G.D., Szeremeta, J. and Jaskuła, M., "Porous Anodic Alumina Formed by Anodization of Aluminum Alloy (AA1050) and High Purity Aluminum", Electrochimica Acta, Vol. 55, No. 14, pp. 4377-4386, 2010.
14. Paz Martínez-Viademonte, M., Abrahami, S.T., Hack, T., Burchardt, M., Terryn, H.," A Review on Anodizing of Aerospace Aluminum Alloys for Corrosion Protection", Coatings, Vol. 10, No. 11 pp. 1106, 2020.

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