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To achieve the repeatability of aerospace thermal components, C/TaC‒SiC composites were fabricated. Cycle ablation and bending tests were carried out. After 3 × 60 s of ablation beyond 2100°C, the mechanical property retention rate was 80.9%. Interestingly, a reaction similar to “ouroboros ring,” in which the cyclic reactions of “TaC being oxidized to Ta2O5 and Ta2O5 being reduced to TaC,” occurred in the central ablation region of C/TaC‒SiC composites. On the one hand, the continuous generation of TaC could prevent liquid state Ta2O5 from being blown off central ablation region, playing a similar role in “water and soil conservation.” On the other hand, liquid Ta2O5 covered the surface of C/TaC‒SiC composites during ablation process, contributing to block the inward permeation of oxidized gases. In addition, novel “Grotto” structures were detected in the transitional ablation region of C/TaC‒SiC composites. The formation reason of the “Grotto” structure has also been discussed. [ABSTRACT FROM AUTHOR]

To inhibit the negative influence of impact on ablation performance of HfC coating reinforced by SiC nanowires (SiCnws/HfC coatings), BN interphases were fabricated and introduced into SiCnws/HfC coatings by chemical vapor deposition. The effect on BN interphase thickness upon SiCnws@BN/HfC coatings performance under impact‐ablation environment was investigated. The interphase thickness was adjusted by changing the deposition time of BN. Impact and ablation tests were carried out by drop hammer and oxyacetylene ablation devices. Among the prepared coatings, the one with 150 ± 20 nm thickness interphase possessed a good performance under impact test, of which the crack propagation path exhibited a significant deflection. After ablation, the coating could still maintain intact surface, because the interphase thickness of 150 ± 20 nm was appropriate to ensure the toughness of the coating and to avoid the porous structure formation. [ABSTRACT FROM AUTHOR]

The slurry and sol‐gel methods were used to introduce SiC nanowires (SiCnws) into the SiCf/HfC‐SiC composites. The microstructures, ablation, and bending behaviors of the SiCnws modified composites prepared by the two methods were compared. The bending strengths of the modified composites obtained by introducing SiCnws by the slurry and sol‐gel methods were 224 ± 19 and 154 ± 14 MPa, respectively. The results showed that SiC fibers with chemical corrosion and thermal damage during the sol‐gel process decreased the bending strength of the SiCnws‐modified SiCf/HfC‐SiC composites. Meanwhile, the pyrolytic carbon interface accompanying corrosion damage in the sol‐gel process led to the degradation of interface function, which hindered the interface debonding and fiber sliding of the composites during the bending test. After ablation, the bending strengths of the two composites were 188 ± 19 and 50 ± 7 MPa, respectively. The bending strength retention of the modified composites fabricated by the slurry method (83.9%) was higher than that (32.5%) of the composites fabricated by the sol‐gel method after ablation. As the composites fabricated by the slurry method exhibited a good ablation resistance under the oxyacetylene flame (∼2350°C). [ABSTRACT FROM AUTHOR]