Effect of substrates on the photocatalytic activity of the composite coating fabricated by detonation sprayed Ti powders
Аннотация
Composite coatings based on titanium oxides were successfully deposited on fine-grained concrete and porcelain tile substrates using a robotic complex for detonation spraying. The study focused on the influence of substrate roughness and composition on the microstructure, phase composition, and photocatalytic properties of the coatings. Dense, uniform coatings with a bimodal lamellar microstructure and thicknesses ranging from 20–30 µm on concrete to 250–300 µm on porcelain tiles were obtained without cracks or significant porosity. It was observed that the phase composition of the coatings, which included a mixture of titanium, anatase, rutile, TiO, and Ti₂O₃ phases, remained unaffected by variations in the substrate composition. Regardless of the substrate material used, all coatings exhibited similar phase constituents. However, the surface roughness of the substrates played a crucial role in determining the microstructure and photocatalytic performance. The rougher concrete surface promoted a higher anatase content, resulting in enhanced photocatalytic activity compared to coatings on smoother porcelain tiles. Coating thickness and porosity did not significantly affect photocatalytic efficiency. Additionally, the kinetic constants of the obtained coatings exceeded those of commercial sol-gel coatings and aligned with values typical for thermally sprayed coatings. The obtained results indicate that composite titanium oxide coatings demonstrate high potential for industrial applications where effective breakdown of organic pollutants on diverse surfaces is required.

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