International Scientific Journals
of Scientific Technical Union of Mechanical Engineering "Industry 4.0"

Thin coatings of aluminum oxide (Al2O3), zirconium oxide (ZrO2) and samarium oxide (Sm2O3) on aluminum alloy Al7SiMg (A356) were prepared by sol-gel method and immersion technique. The materials were characterized in detail by X-ray diffraction. The luminescent properties at room temperature were also investigated. Luminescence analysis showed that the Al2O3 coating containing ZrO2 exhibits broad excitation and emission bands, peaking at 328 nm and 392 nm, respectively. Photoluminescence data for the Al2O3 coating containing ZrO2 and Sm2O3 indicated effective excitation at 404 nm and strong broadband emission, which is due to the co-emission of ZrO2 and Sm2O3. Chromaticity coordinate analysis revealed that Al2O3 coating containing ZrO2 and Al2O3 coating containing ZrO2 and Sm₂ O₃ emit in the blue-purple and pale pink regions, respectively.The chromaticity coordinates, color purity and CIE (Commission Internationale de L’Eclairage) color-correlated temperature were determined.

Thin coatings of zirconia oxide (ZrO2) and samarium oxide (Sm2O3) on glass have been prepared by using sol-gel method and dip coating technique. Materials were characterized in detail by X-ray diffraction. The luminescent properties at room temperature were also investigated. Excitation and emission spectra of ZrO2 coating consists of broad bands with maximums at 318 and 365 nm respectively.
The photoluminescence measurements of samarium coating suggest that can be efficiently excited with 700 nm and consist of emission bands centered at 567, 603, 639 and 707 nm, consistent with characteristic Sm3+ transitions. The CIE (Commission Internationale de L’Eclairage) chromatic coordinates, color purity and color correlated temperature were determined.

Obtained experimental self-cleaning coatings (based on compositions with the participation of Eu2O3), applied by the sol-gel method on glass slides. The luminescence of the obtained thin layers of different ratios of the compositions were investigated. A strong emission from the 5D0 level of Eu3+ ions was registered under near UV (392 nm) excitation using the 7F0 → 5L6 transition. The values of the integrated fluorescence intensity ratio R (5D0→7F2)/(5D0→7F1) was calculated to give information about the degree of asymmetry in the vicinity around the active ions, suggesting a location of Eu3+ in non-centrosymmetric sites. The highest Eu3+ luminescence is observed in sample with 3 layers coating. The experimental results represent a prerequisite for the development of a series of additional compositions and a detailed technological regime for obtaining various modifications of resistant, long-lasting self-cleaning coatings, potentially applicable to photovoltaic panels.