Excellent Electromagnetic Wave Absorption of Iron‐Containing SiBCN Ceramics at 1158 K High‐Temperature

Abstract

The enhancement of electromagnetic wave absorption at high-temperature as well as oxidation is cutting-edge issue in current electromagnetic functional materials due to the strong demand of stealth aircrafts or aero-engines working in harsh environments. In this contribution, the excellent electromagnetic wave absorption at 1158 K (885 C) with a minimum reflection coefficient (RC min ) of À12.62 dB and a wide effective absorption bandwidth (RC min < -10 dB) of 3.2 GHz was achieved on iron-containing siliconboron carbonitride (SiBCN) monolithic ceramics by using polymer-derived ceramics (PDC) route, setting a new record for EM wave absorption materials at high-temperature. In addition, these materials exhibited desirable mechanical properties and excellent hightemperature resistance until 1400 C in argon atmosphere and 885 C in air atmosphere, respectively. This ingenious strategy is generally benefiting the promotion of EM wave absorption materials with great potential in antenna housings, radomes, areo-engines, and stealth aircrafts in harsh environments.With rapid development of electronic equipments in wireless communication, medical and aerospace fields, electromagnetic (EM) wave transparency, absorption, and shielding are important issues. [1][2][3][4] EM wave absorbing materials are mainly deployed in high-power electronic instruments, satellite communication, radar, stealth ships, and aircrafts, which can eliminate adverse EM waves by converting into thermal energy. However, the stealth aircrafts or aero-engines are working in harsh environments such as high temperature and oxidation, the enhancement of electromagnetic wave absorption and stealth performance at high temperature more than 600 C (873 K) is cutting-edge issue in current electromagnetic functional materials.In this field, metamaterials, ferrites, carbon family materials (carbon black, carbon fibers (CFs), carbon nanotubes (CNTs), graphite flakes, graphene foams, or graphenes), metal-carbon nano-hybrids (Fe 3 O 4 /CNTs/CFs, Fe 3 O 4 /graphene capsules, Co-carbon nanotubes-graphene, Co-Carbon metal-organic framework), core/shell hierarchical nanostructures and dielectronic ceramics, 2D transition metal carbides (MXenes) show favorable EM absorbing performance in ambient environment. [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] However, at high temperature more than 873 K (600 C), most of ferrites are limited by low Curie temperature (T c ), for example, 360-440 C for Ba 3 Me 2-Fe 24 O 41 (Me ¼ Co, Cu, Ni) and 570 C for Ni-Zn ferrites. [5] Above T c , the ferrite will be converted to paramagnetic and lose EM wave absorption functionality. For metamaterials, MXenes, and carbon family materials, they always suffer from the thermolysis and oxidation at high temperature more than 600 C (873 K).With resistance to both high temperature and oxidation, silicon carbide (SiC) or silicon nitride (Si 3 N 4 )-based ceramics are important dielectronic type EM wave absorbing materials in harsh environments. The SiC-based materials, including SiC ...

Enhanced electromagnetic wave absorbing properties of Si‐O‐C ceramics with in‐situ formed 1D nanostructures

“…When the pyrolysis temperature is 1200°C, the amount of 1D nanostructures obviously increase and form a network in Figure 2E, which indicates that the increase in pyrolysis temperature is beneficial to the growth of 1D nanostructures. 6,8,13 Figure 3 shows the TEM images of the identified 1D nanostructures formed in the Si-O-C bulk ceramics. The formed phases are beneficial to improve the EMW absorbing property because of the formed grain boundaries, defects, and dangling bonds, which are able to generate interfacial polarization and associated relaxation under the EMW irradiation.…”

“…c is the light velocity in vacuum, t is the thickness of the absorber, f is the microwave frequency. derived from different precursors pyrolyzed with the presence or absence of catalyst, 1,6,9,10,13,14,16,17,20,[27][28][29][30][31][32][33] the metal-loaded carbon material as a kind of wave absorbing filler incorporated into the pyrolyzed matrix with low conductivity also presents excellent wave absorbing properties, such as Co and Fe 3 O 4 . The EMW absorbing performance of materials is depended on the complex permittivity and permeability ( r = � − j �� ), and for nonmagnetic SiC material, � = 1 and �� = 0.…”

“…10 Duan et al prepared Si-O-C ceramics by pyrolyzing the hyperbranched ferrocene-containing polysiloxane at 1000-1450°C and found that the sample with 1 wt% Fe at a thickness of 2.64 mm pyrolyzed at 1100°C had the best absorption performance with the EAB of 3.5 GHz. 13 According to the recent literatures, 1D nanostructured carbon 1,10,14,15 and SiC nanowires 12,16,17 can be in situ generated by catalytically pyrolyzing precursors, while the in-situ generation of the phase more which is favorable for the EMW absorbing properties is rarely reported. 1 Han et al prepared hierarchical graphene/SiC nanowire networks in Si-O-C matrix sintered at 1400°C with the EAB of 3.9 GHz.…”

Improved dielectric permittivity and retained low loss in layer-structured films via controlling interfaces

“…In recent years, enormous attention and research enthusiasm have been devoted to high dielectric (high-k) materials for their wide applications in actuators [1,2], antennas [3], capacitors [4][5][6][7], wave-transparent (or absorbing) devices [8][9][10][11][12][13], and other electronic devices [14][15][16][17][18][19][20][21][22]. Most conventional highk materials are ceramic or ceramic composites, but their applications are seriously restricted by their intrinsic frangibility, high density, poor plasticity, and low breakdown strength.…”

High temperature self-healing SiBCN ceramics derived from hyperbranched polyborosilazanes

“…S3. After oxidation, the Si2p spectra for C2 can be fitted into Si-C bond (SiC) at 100.4 eV, Si-N bond (Si 3 N 4 ) at 101.8 eV, and Si-O bond in (SiO 2 ) at 103.2 eV, respectively [39][40][41][42][43][44]. And the peak at 186.9, 190.4, and 193.1 eV is Table 2.…”