Improvement dielectric and microwave properties of SiC f /SiC-AlPO 4 composites prepared by precursor infiltration and pyrolysis process

Preparation of SiCf/Si–O–C composites by impregnation pyrolysis of polysiloxane and its electromagnetic wave absorption properties

“…Theoretically, the electrical conductivity of materials is connected with their ε ″ values, 37 which can be expressed as follows: $$$$\begin{equation}{\varepsilon ^{{\prime\prime}}} = \varepsilon _{relax}^{{\prime\prime}} + \frac{\sigma }{{2\pi f{\varepsilon _0}}}\end{equation}$$$$where ε ″ relax is the electron relaxation polarization, f is the frequency, and ε 0 is the permittivity of free space ( ε 0 = 8.854 × 10 −12 F/m).…”

“…Figure 7D shows that the impedance matching ratio at 1300 • C is only about 0.35, which means that more EMW will be reflected by the composites surface, resulting in the deterioration of the EMW absorption performance. Theoretically, the electrical conductivity of materials is connected with their ε″ values, 37 which can be expressed as follows:…”

The Influence of SiO2 + SiC + Al (H2PO4)3 Coating on Mechanical and Dielectric Properties for SiCf/MWCNTS/AlPO4 Composites

“…Continuous fiber-reinforced ceramic matrix composites (SiC f /SiC [ 7 ], SiC f /C [ 8 ], C f /C [ 9 ], C f /SiC [ 10 ], and SiC f /AlPO 4 [ 11 ]), showing excellent fracture toughness, good thermal stability, and environmental durability, have been evaluated and modified for use as structural electromagnetic wave-absorbing materials. Especially, continuous SiC fiber-reinforced AlPO 4 (SiC f /AlPO 4 ) composites have demonstrated good potential [ 12 , 13 , 14 ]. Their low dielectric constants provide the opportunity to tailor the dielectric properties and wave absorbing abilities by the addition of conductive fillers (carbon black, carbon nanotube, and graphene).…”

Preparation and properties of aluminum phosphate‐polyethersulfone laminated composites modified by aluminosilicate fiber fabric

“…However, the great brittleness, poor wear resistance, and complicated manufacturing process of this material have imposed restrictions on its practical applications as structural and functional composites. In order to overcome the above‐mentioned defects and further improve the dielectric property of AlPO 4 , all kinds of reinforcement materials, for instance, mullite fibers , SiC fiber cloth , cyanate ester , aluminum borate whisker , and so on, have been applied in the fabrication of AlPO 4 ‐matrix composites to achieve better mechanical properties and lower dielectric dissipation factor.…”