Al-based coating was prepared with Al-based cored wire by arc spraying. The properties of high-temperature oxidation resistance and corrosion resistance of Al-based coating were compared with those of Fe-Al coating and 45CT coating. The property of H 2 S corrosion resistance of Al-based coating was compared with that of A304 stainless steel and Fe-Al coating. The results suggest that the Al-based coating has better properties of high-temperature oxidation resistance and corrosion resistance than Fe-Al coating and 45CT coating. Al-based coating has better property of H 2 S corrosion resistance than A304 stainless steel and Fe-Al coating.

The effect of nano and microstructured powders in cored wires on formation and properties of Fe-TiB 2 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% TiB 2 coatings reveals a dispersion of fine ceramic particles and less scattering of hardness, which improved the wear resistance and changed the abrasion mode.

Nanostructured ceramic composite coatings were deposited by high velocity arc-spraying. It was found that metal-clad powders exhibited better thermal conductivity and atomization capabilities when compared to mechanically blended powders. The Surface Rockwell hardness values of the nanostructured ceramic composite coatings were similar to those of the conventional coatings (from 66.7 to 72.8), however, the bond strength of the nanostructured coatings measured via the GB9796-88 standard reached values of 60 MPa, whereas the bond strength of the conventional coatings stayed below 40 MPa. The microstructure of the high velocity arc sprayed nanostructured ceramic coatings was analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The coatings exhibited the typical lamellar structure of thermal spray coatings. The surface of the nanostructured composite coatings was smoother than that of the conventional ones, and their microstructures were denser, showing lower levels of impurity.