Preliminary Study on Low-Pressure Cold Spray Process Parameters: Effect on Mechanical and Photocatalytic Properties of TiO2 Coatings

Abstract

AbstractThe TiO2 photocatalytic coatings’ most important properties are durability and photocatalytic activity. Those features form a basis to determine its degree of usefulness. In this study, the self-synthesized amorphous TiO2 powder was used for low-pressure cold spray photocatalytic coatings. Two strategies were adopted to change the surface properties, which can influence the mechanical properties of the coatings: (I) reduction of the scanning step and (II) filling the depressions in the already sprayed coating with the second layer. The coatings surface topography (measured by roughness and waviness) results showed that the first strategy makes coatings thicker, with a more uniform surface. The second strategy leads to obtaining more rough surfaces with no significant change in the thickness. The preliminary study results indicate that the first strategy was superior to the other one, in terms of both mechanical (described by cohesion and adhesion) and photocatalytic (measured by the decomposition of methylene blue under UV) properties of the coatings. Graphical Abstract