Strong and thermostable hydrothermal carbon coated 3D needled carbon fiber reinforced silicon-boron carbonitride composites with broadband and tunable high-performance microwave absorption

Enhanced Electromagnetic Wave Absorption for Y2O3-Doped SiBCN Ceramics

“…This leads to the dispersion effect, and the spectral peaks are broadened because of the dipole relaxation . According to Debye’s theory, the relationship between the real part (ε′) and the imaginary part (ε″) of permittivity is as follows: , where ε s is the electrostatic dielectric constant and ε ∞ is relative permittivity at the high frequency. According to eq , the semicircle in Figure d is normally attributed to the polarization relaxation between different phases and the interfaces between them.…”

Recent advance in three-dimensional porous carbon materials for electromagnetic wave absorption

“…In the end, 3D porous carbon-based EWAMs have promising CoNi@N-doped CNT arrays −49.82 -3.5 20 [154] Carbon fiber felt/SiBCN −52.08 -1.8 30 [155] SiOC/carbon fiber felt −62.9 -2.72 30 [156] SiOC and SiC nanowires/carbon fiber felts −48.2 3.06 3.6 50 [157] Carbon cloth@N-doped porous carbon/CoS 2 −59.6 7.2 2.8 30 [158] prospects and deserve our unremitting efforts. Many of the results summarized here provide a good starting point for further studies and trials, but also that there is a lot of room for the improvement of 3D porous carbon-based EWAMs.…”

“…These 3D carbon materials possessed interconnected conductive network and plentiful pores, which was in favor of EMW absorption. Dong's group [155] prepared a carbon fiber felt with hydrothermal carbon (HC) and silicon-boron carbonitride (SiBCN) coating (HC-CF/SiBCN). HC coating protected the carbon fiber felt at low temperatures, while SiBCN, as a high-temperatureresistant component, ensured the oxidation resistance of the material above 1000°C.…”

Phase-Transformation Nanoparticles Synchronously Boosting Mechanical and Electromagnetic Performance of SiBCN Ceramics

“…The t-HfO 2 /c-hb-PBSZ complex was prepared by blending different amounts of t-HfO 2 nanoparticles (10,20,30,40, and 50 wt %) and c-hb-PBSZ powder, as shown in Figure 1. The hb-PBSZ precursor was synthesized based on a former report.…”

“…The research on advanced electromagnetic (EM) wave absorbing materials has been a hot spot in tackling the problems associated with EM interference in harsh environments. − Aside from excellent absorption performance, , the combination of fine loading capability, high-temperature oxidation resistance, and light weight , also need to be considered for advanced EM wave absorbing materials. Silicon-based ceramics have been widely investigated because of their high temperature resistance, superior oxidation resistance, and creep resistance properties. , As a typical silicon-based ceramic, precursor-derived silicoboron carbonitride ceramic (PDC-SiBCN) demonstrates structural controllability, compositional homogeneity, low-temperature synthesis, and processing flexibility. − These prominent features make it more effective in preparing fibers, films, and coatings for various applications in extreme environments. − In particular, owing to its adjustable dielectric properties, PDC-SiBCN has an absolute advantage in EM wave absorption. − However, the main challenge in developing PDC-SiBCN as a load component is its high shrinkage, which results in the formation of defects during organic to inorganic transitions due to the release of gases . Moreover, their inherent brittleness owing to the intrinsically strong and directional covalent bonds cannot be ignored. , These characteristics lead to the significantly low loading capability of PDC-SiBCN ceramics .…”