Abstract:Carbon-based ceramic tile is urgently needed high-temperature anti-insulation materials in the thermal protection system of hypersonic vehicles due to the high temperature resistance, low density, and low thermal conductivity. But the material is easy to destroyed by oxidation erosion and ablation. In this experiment,, the Ni-Cr spinel high-emission ablation-resistant anti-oxidation coating was prepared by atmospheric plasma spraying technology on the surface of a carbon-based ceramic thermal insulation tile substrate on which a ZrB2-SiC-glass inner coating has been prepared. The phase structure and microstructure of the powder and coating were examined by XRD and SEM, and the coating was ablated by oxygen-acetylene flame. The results show that when the mole ratio of Cr2O3 and NiO is 1: 1.2, the pure NiCr2O4 spinel powder can be obtained by the solid phase reaction at 1200 ℃ for 2 h. To get complex spinel powder, 15 wt.% TiO2 and 25 wt.% MnO2 were added to the former consititute system and the same manufacture method was applied. The emissivity of NiCr2O4 high-emission coatings and NiCr2O4-doped high-emission coatings reached 0.955 and 0.954 respectively in the 1-22 μm band. The NiCr2O4 was slightly decomposed after spraying, and the emissivity was reduced. The Mn-Ti doped NiCr2O4 phase structure was stable, no decomposition, and the emissivity was stable. The result of the ablation shows that the surface temperature of Mn-Ti doped NiCr2O4 coating lower than NiCr2O4 coating by 240 ℃ and the infrared radiation performance is far higher than NiCr2O4 coating, when the flame temperature is 2000 ℃. Mn-Ti-doped NiCr2O4 coating is more stable than NiCr2O4 coating at high temperature, which keeps high emission performance. The Mn-Ti doped NiCr2O4 coating keeps stable after the 2000 ℃, 300 s ablation assessment, which perform a better radiation and ablation resistance.