Electromagnetic wave absorbing properties and oxidation resistance of CNTs/SiC composite bonded with CNTs@calcium aluminate cement

• Published in: Ceramics international 2024-10, Vol.50 (19), p.35007-35018
• Main Authors: Lei, Changkun, Ding, Donghai, Xiao, Guoqing, Hou, Xinmei, Wang, Enhui, Zhou, Renbiao, Feng, Chunzhuo
• Format: Article
• Language: English
• Subjects: Castable CNTs/SiC composites; CNTs@CAC; EMW absorption property; Flexural strength; Oxidation resistance
• ISSN: 0272-8842; 1873-3956
• DOI: 10.1016/j.ceramint.2024.06.309

To achieve homogeneous dispersion of CNTs in the SiC-based composites, calcium aluminate cement encased carbon nanotubes agglomerate (CNTs@CAC) was synthesized and used as a binder for castable CNTs/SiC composite. The EMW absorption, physical and mechanical properties of CNTs/SiC composite bonded with CNTs@CAC were investigated. SiC nanowires were in-situ generated in CNTs/SiC composite using CNTs from CNTs@CAC as the template. The uniform conductive network of SiC nanowires and CNTs and multiple heterogeneous interfaces promoted the dissipation of the incident EMW by conductance loss and polarization loss. As a result, the CNTs/SiC composite bonded with CNTs@CAC achieved a maximum EAB of 4.0 GHz in the X-band (8.2–12.4 GHz) at a thickness of 2.4 mm. Even after oxidation at 1000 °C for 8 h, the EAB covered the entire X-band. Moreover, RCS simulations were carried out via CST. The RCS values of CNTs@CAC bonded CNTs/SiC composites were all lower than those of mechanically mixed Secar71 and CNTs bonded CNTs/SiC composites under different incident angles of EMW, indicating that CNTs/CAC bonded CNTs/SiC composites can attenuate more electromagnetic energy. The bulk density of CNTs/SiC composite bonded with CNTs@CAC was 1.85 g/cm3, and flexure strength was 22.8 MPa.