Oxidation resistance, ablation resistance and in situ ceramization mechanism of Al-coated carbon fiber/boron phenolic resin ceramizable composites modified with Ti3SiC2

• Published in: Ceramics international Vol. 49; no. 20; pp. 32490 - 32502
• Main Authors: Deng, Zongyi, Shi, Minxian, Huang, Zhixiong, Yu, Xiaobo, Wu, Yue, Yang, Xueyuan
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.10.2023
• Subjects: Ablation mechanisms; Al coatings; B. Composites; C. Thermal properties; Ceramization evolution; MAX phase ceramic; Ablation mechanisms; B. Composites; Al coatings; MAX phase ceramic; Ceramization evolution; C. Thermal properties
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2023.07.211

Inherent defect of easy oxidation limited further application of carbon fiber/phenolic resin composites in hostile environments. Herein, a combined strategy of matrix modification and fiber coating was proposed to fabricate a novel ceramizable composite containing Al-coated carbon fibers and Ti3SiC2 toward thermal protection materials (TPM), which offered a promising solution to challenge facing long-term thermal protection and load-bearing subject to severe oxidation corrosion and ablation in hypersonic vehicle applications. Oxidation resistance, mechanical strength evolution, phase evolution, microstructure evolution and mechanical strength failure mechanism at elevated temperatures were studied based on thermogravimetric analysis, static ablation test, mechanical test, X-ray diffraction analysis, and scanning electron microscopy coupled with energy dispersive X-ray analysis. The resulting composites exhibited outstanding oxidation resistance, with residue yield at 1600 °C and flexural strength at 1400 °C as high as 87.7% and 31.7 MPa, respectively. It was found that dense multiphase ceramics formed by reactions between Ti3SiC2, O2, pyrolytic carbon (PyC) and N2, acted as oxygen barriers and self-healing agents during static ablation. Besides, the resulting composites exhibited satisfactory ablation resistance and the linear ablation rate was as low as 0.00853 mm/s. Furthermore, ablation mechanisms were revealed based on phase identification, microstructure characterization and thermodynamic calculation analysis. It was revealed that multiphase ceramics composed of PyC, Al coatings, Ti3SiC2, TiC, Al2OC and AlB2 contributed great to the ablation resistance during oxyacetylene ablation. [Display omitted] •A combined strategy of matrix modification and fiber coating was proposed to prepare a novel ceramizable composite containing boron phenolic resin, Al-coated carbon fibers and Ti3SiC2.•The resulting composites exhibited outstanding oxidation resistance, with the residue yield at 1600 °C and flexural strength at 1400 °C as high as 87.7% and 31.7 MPa, respectively, and satisfactory ablation resistance, with the linear ablation rate as low as 0.00853 mm/s.•Readily oxidized pyrolytic carbon was fixed by a carbothermal reduction-nitridation reaction with TiO2 and N2 to yield refractory TiC0.7N0.3 during static ablation.•Multiphase ceramics composed of PyC, Al coatings, Ti3SiC2, TiC, Al2OC and AlB2 contributed great to the ablation resistance during oxyacetylene ablation.