Dielectric and microwave absorption properties of fluoride-doped MWCNT/Si3N4 composite

• DOI: 10.1007/s10854-019-02836-2
• Publication Date: 2020-01-04T11:03:04Z
• Authors: Adil Saleem; Yujun Zhang; Hongyu Gong; Muhammad K. Majeed; Xiao Lin; Jie Jing; Mingming Sheng; Cuncai Zhao
• Keywords: Reflection loss; Dielectric loss

Herein, silicon nitride (Si3N4) ceramic reinforced with multi-walled carbon nanotubes (MWCNT) was processed by hot press sintering using fluoride additives (AlF3 and MgF2). The X-ray diffraction patterns show that a SiC layer is formed owing to the reaction between Si and MWCNT, leading to a good bonding between MWCN and Si3N4 matrix. The microstructural results revealed that the fluoride additives lead to improve the densification and phase transformation through liquid phase mechanism. The effect of various concentrations of MWCNT on dielectric and microwave (MW) absorption properties of MWCNT/Si3N4 composites in a frequency range of 8.2 to 12.4 GHz (X-band) was investigated. The dielectric parameters have revealed that the complex permittivity of MWCNT/Si3N4 composites have also been enhanced with the addition of MWCNT content. Moreover, the MW absorption properties were improved with the addition of MWCNT, and the minimum value of reflection loss (RL) was achieved − 8.65 dB (~ 90% absorption), indicating that the MWCNT/Si3N4 composites might exhibit a promising prospect as MW absorber.