Phase constitutions of MoSiN anti-oxidation multi-layer coatings on CC composites by fused slurry

To improve the oxidation resistance of MoSi fused slurry coating fabricated in vacuum, MoSiN multi-layer coatings were synthesized on C/C composites in nitrogen atmosphere by fused slurry using same Mo and Si element powders. The phase compositions and microstructures were characterized by X-ray diffractometry (XRD), optical microscopy (OM), scanning electron microscopy (SEM) with energy-dispersive spectroscopy (EDS). The results indicate that the MoSiN coating contains SiC inner layer and MoSi2/Si main layer, which was similar with MoSi coating. Additionally, a thin outer layer with nano-filiform morphology has been found on the coating surface, which consists of SiC, Si3N4, AlN, Al2O3 and sialon phase. Oxidation experiments show that the MoSiN multi-layer coating exhibits excellent oxidation resistance at 1400 °C and anti-oxidizing potential ability at 1450 °C.