In order to improve the oxidation resistance of carbon/carbon (C/C) composites,a SiC/C-AlPO4 multi-layer coating was fabricated on the C/C composites by a simple and low-cost method.The internal SiC bonding layer was prepared by a two-step pack cementation process and the external C-AlPO4 coating was deposited by hydrothermal electrophoretic deposition process.Phase compositions and microstructures of the as-prepared multi-layer coating were characterized by X-ray diffraction (XRD),scaning electron microspocy (SEM) and energy dispersive spectrometer (EDS).Anti-oxidation properties,oxidation behavior and the failure behavior of the coated composites were investigated.The results indicate that the multi-layer coating exhibits obviously two-layer structure.The inner layer is composed of β-SiC,α-SiC phase with a scale of silicon phase.The outer layer is composed of cristobalite aluminum phosphate (C-AlPO4) crystallites.The SEM observation shows the good bonding between the inner and outer layers.The multi-layer coating displays an excellent oxidation resistance in air in the temperature range from 1573 to 1773 K,and the corresponding oxidation activation energy of the coated C/C composites is calculated to be 117.2 kJ/mol.The oxidation process is predominantly controlled by the diffusion of O2 through the C-AlPO 4 coating.The failure of the multi-layer coating results from the generation of the microholes that may be left by the escape of the oxidation gases. In order to improve the oxidation resistance of carbon / carbon (C / C) composites, a SiC / C-AlPO4 multi-layer coating was fabricated on the C / C composites by a simple and low-cost method. was prepared by a two-step pack cementation process and the external C-AlPO4 coating was deposited by hydrothermal electrophoretic deposition process. Compositions and microstructures of the as-prepared multi-layer coating were characterized by X-ray diffraction (XRD), scaning Anti-oxidation properties, oxidation behavior and the failure behavior of the coated composites were investigated. The results indicate that the multi-layer coating exhibits obviously two-layer structure.The inner layer is composed of β-SiC, α-SiC phase with a scale of silicon phase. The outer layer is composed of cristobalite aluminum phosphate (C-AlPO4) crystallites. The SEM observation shows the good bonding between the inner and oute r layers. The multi-layer coating displays an excellent oxidation resistance in air in the temperature range from 1573 to 1773 K, and the corresponding oxidation activation energy of the coated C / C composites is calculated to be 117.2 kJ / mol. is predominantly controlled by the diffusion of O2 through the C-AlPO 4 coating. Failure of the multi-layer coating results from the generation of the microholes that may be left by the escape of the oxidation gases.