In view of their potential applications as selective solar absorbers, chromium coatings on float glass substrates were nano/micro structured by femtosecond laser in air. Raman and X-rays diffraction investigations confirmed the formation of an ultra-porous a-Cr(sub2)O(sub3) layer at the surface; higher is the input laser power, enhanced is the crystallinity of the a-Cr(sub2)O(sub3) layer. The a-Cr(sub2)O(sub3) layer with the Cr underneath it in addition to the photo-induced porosity acted as a classical ceramic–metal nano-composite making the reflectance to decrease significantly within the spectral range of 190–1100 nm. The average reflectance decreased from 70 to 2%.
Reference:
Kotsedi, L, Nuru, ZY, Mthunzi, P, Muller, TFG, Eaton, SM, Julies, B, Manikandan, E, Ramponi, R and Maaza, M. 2014. Femtosecond laser surface structuring and oxidation of chromium thin coatings: black chromium. Applied Surface Science, vol. 321, pp 560-565
Kotsedi, L., Nuru, Z., Mthunzi, P., Muller, T., Eaton, S., Julies, B., ... Maaza, M. (2014). Femtosecond laser surface structuring and oxidation of chromium thin coatings: black chromium. http://hdl.handle.net/10204/8088
Kotsedi, L, ZY Nuru, P Mthunzi, TFG Muller, SM Eaton, B Julies, E Manikandan, R Ramponi, and M Maaza "Femtosecond laser surface structuring and oxidation of chromium thin coatings: black chromium." (2014) http://hdl.handle.net/10204/8088
Kotsedi L, Nuru Z, Mthunzi P, Muller T, Eaton S, Julies B, et al. Femtosecond laser surface structuring and oxidation of chromium thin coatings: black chromium. 2014; http://hdl.handle.net/10204/8088.
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