Ablation resistance of SiC-modified nanocomposite ceramic coating prepared by LPDS method on titanium alloy

To enhance the ablation resistance of Ti6Al4V alloy, a SiC-modified nanocomposite ceramic coating was fabri-cated by a novel one-step liquid plasma-assisted particle deposition sintering (LPDS) method. A microarc oxidation (MAO) ceramic coating was prepared on the surface of titanium alloy as a comparison. The micro -morphologies and formation mechanisms of two ceramic coatings were investigated with the assistance of scanning electron microscopy (SEM), X-ray diffractometer (XRD), and transmission electron microscopy (TEM). The thickness of the SiC nanocomposite coating (about 39 mu m) was significantly increased by 129% compared to the MAO coating (about 17 mu m). Additionally, ablation tests of Ti6Al4V alloy, MAO coating, and SiC nano -composite coating were conducted at 1000 degrees C using a butane gas lance. Then, the variation of microstructure, phases, elemental composition, and thickness before and after ablation was also comparatively analyzed. The results indicate that the SiC nanocomposite coating exhibits the smallest thickening (29 mu m) after ablation at 1000 degrees C for 360 s, which is 39% and 46% compared with the Ti6Al4V substrate and MAO coating, respectively. The nanocomposite coating is intact and cracks-free after the ablation test. SiO2, formed during the ablation of SiC nanocomposite coatings, blocks oxygen diffusion into the substrate, which plays a protective role in the coating. Therefore, the SiC nanocomposite coating by a novel LPDS technique exhibits superior ablation resis-tance to enhance the thermal protection performance of titanium alloy substrate.