Improvement of solid cold sprayed TiO2–Zn coating with direct diode laser

Abstract In flame spraying, arc spraying, and plasma spraying it is important that the material melts completely. With HVOF spraying, partial melting is sufficient to achieve a high-quality coating. The reason for this is that the particle velocities upon impact on the substrate are considerably higher in HVOF spraying. In the new solid cold spray process, the coating is formed by high-velocity particles impacting with the substrate to be coated. These particles bond mechanically with the substrate by way of plastic deformation only. The performance of a newly developed solid cold spraying apparatus and the photo-catalytic properties of TiO 2 –Zn coatings were examined. The results indicated that particle velocity and the hardness of substrate had a more significant effect on the quantity of zinc adhered than spraying distance did. In this research, a direct diode laser was utilized for laser treatments of cold sprayed composite coatings. The laser treatment is the present subject of research in order to obtain denser coatings with good adhesion to the substrate.