Ablation property and oxide scale evolution of Y2O3 modified C/C-SiC composites fabricating via precursor infiltration and pyrolysis method

摘要

? 2022Employed precursors of Y(NO3)3·6H2O and polycarbosilane, Y2O3 doped C/C-SiC composites were prepared by utilizing precursor infiltration and pyrolysis method. Results show that Y2O3 alters the composition of C/C-SiC composites with the generation of β-Y2Si2O7 and Y2O3 together with slight Y2SiO5, Y4.46(SiO4)3O and Y2C3. During ablation, β-Y2Si2O7 is stable and directly liquefied to rapidly fill in the empties in the substrate; the other three are transformed to δ-Y2Si2O7, evolving the oxide scale from SiO2-β-Y2Si2O7-Y2O3 (semi-fused) layer to SiO2-β-Y2Si2O7-δ-Y2Si2O7 ones. The ablation rates after ablation for 120 s were respectively 0.210 mg/s and 14.58 μm/s, severally decreased by 57.32 and 8.59 compared with that for 60 s. Further evaporation of SiO2 is suppressed and reconcilement of oxide layer is hence confirmed, implying decent anti-ablation resistance of oxide layer.