Abstract
The effect of nano and microstructured powders in cored wires on formation and properties of Fe-TiB2 composite coatings by high velocity arc spraying (HVAS) was investigated. Six cored wires filled with different average ceramic particle sizes (20-40 nm, 2 µm, and 420 µm) and fine powder contents (0, 8, 16, 20, 24, 32wt.%) were sprayed. The flattening behavior of sprayed particles was characterized and compared by using optical microscopy (OM) and 3D Surface Profiler. The microstructure of the coatings and phase compositions were characterized by means of Laser Confocal Scan Microscopy, SEM, EDAX and XRD. Hardness and wear properties were evaluated. The results showed that the splat shape of the cermets has a transitional tendency to change from a distorted heavy splash to a disk with little splash with (i) increasing the percentage of fine ceramic particles and (ii) decreasing coatings porosity. Fe –2 µm 32% TiB2 coatings reveals a dispersion of fine ceramic particles and less scattering of hardness, which improved the wear resistance and changed the abrasion mode.