The effect of laser-treated surface patterns on deposition films via Solution Precursor Plasma Spray process

In “Solution Precursor Plasma Spray” process, the fine particles would follow the impacting gas flow parallel to the deposited substrate surface instead of perpendicularly impacting on the substrate. Therefore, the microreliefs on the substrate surface should play more important role, representing the “catching ability” of small particles to build-up coatings. It should be noted that upon gas flow impacting on the substrate, the resulting lateral flow would spread in various directions. In this work, in order to study effect of directions of surface roughness and the density of surface roughness on the deposition efficiency, the artificial “line-pattern” surface roughness was prefabricated by “laser surface texturing” technology, which was composed by a series of parallel grooves. The directions of grooves are perpendicular or parallel or inclined to the main moving path of plasma torch. ZnO and Co₃O₄ films from low and high solution concentrations were deposited by SPPS route on these pre-fabricated Ni substrates. The resulting samples were characterized by SEM, XRD and 3D profiles. It was found that small particles prefer to deposit on the two sides of grooves rather than inside of them and the surface pattern play less effect on the coatings from high solution concentration.