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Developing high-temperature microwave absorption material with light weight is crucial. In this work, Ti3SiC2/Na3Zr2Si2PO12 composites were exploited as light microwave absorption material at high temperature by plasma spraying and vacuum sintering for microstructure, phase, dielectric property, and microwave absorption property study. Results showed that both the preparation method and Ti3SiC2 concentration had vital influences on the dielectric properties and microwave absorption properties of Ti3SiC2/Na3Zr2Si2PO12 composites. The denser Ti3SiC2/Na3Zr2Si2PO12 ceramics had higher complex permittivity than that of Ti3SiC2/Na3Zr2Si2PO12 coatings with lower density, which could obtain better microwave absorption property in thinner thickness with less Ti3SiC2 content. As the content of Ti3SiC2 increased, the complex permittivity of both Ti3SiC2/Na3Zr2Si2PO12 coatings and ceramics improved due to the increased interfacial polarization and conduction loss. The optimum microwave absorption property was obtained in Ti3SiC2/Na3Zr2Si2PO12 ceramic with 10% Ti3SiC2 content, which had a bandwidth of 4.2 GHz and minimum reflection loss (RLm) of − 14.4 dB in 1.7 mm.

Recently, high-temperature stability is a challenge in a number of microwave absorption materials. Hence, researchers are still searching for a novel material system preferably with a high-temperature resistance to be applied in the field of microwave absorption. Here, in the current study, toward this aim, lanthanum (La)-doped strontium titanate (SrTiO3) blended with TiO2 were fabricated by hot-press sintering in a vacuum. The as-prepared samples are denoted as TiO2–Sr1−xLaxTiO3 with x varying from 0.1 to 0.3 in steps of 0.1. Scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscope (XPS), and microwave vector network analyzer were carried out to study their morphology, phase composition, structure, and electromagnetic and microwave absorption properties, respectively. It is revealed that the La atom was efficiently doped at the Sr-site in SrTiO3. Benefiting from the tunability of its dielectric and impedance properties, TiO2–Sr1−xLaxTiO3 can be utilized in a highly efficient way to absorb microwave radiations with a decent design. Results illustrated that TiO2–Sr1−xLaxTiO3 (x = 0.2) with a thickness of only 0.42 mm exhibits a high microwave absorption efficiency of −40.89 dB and can achieve a 2.82 GHz bandwidth of reflection loss value below −5 dB. Thus, TiO2–Sr1−xLaxTiO3 composites ceramics can be served as an opening opportunity for the application of high-temperature stability and tunable high-performance effectiveness microwave absorption materials in stealth technology and information security.

Gadolinium (Gd)-doped perovskite SrTiO3 combining with Al2O3, Al2O3−Sr(1−x)GdxTiO3 (x varying from 0 to 0.3 in steps of 0.1) composite ceramics was synthesized by hot-press sintering in a vacuum. X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectrometer (EDS), four-probe testing instrument, and vector network analyzer were utilized to study their phase and composition characteristics, micromorphology, electrical conductivity, electromagnetic and microwave-absorbing properties, respectively. The XRD, SEM, and EDS results demonstrated that Gd atoms were successfully doped into SrTiO3 crystal and substituted the Sr sites. As a result, Al2O3−Sr(1−x)GdxTiO3 with x = 0.2, which has the advantage of an ultra-thin thickness (0.341 mm), exhibits excellent absorbing properties with a broad bandwidth (90% microwave absorption) of 4.07 GHz in the X band. Furthermore, the present investigation illustrated that Al2O3−Sr(1−x)GdxTiO3 (x = 0.1, 0.2, and 0.3) could be applied in the X band for microwave absorption, with broadband width and ultra-thin thickness (≤ 0.35 mm), by controlling the molar ratios of Gd and the thickness.

The SiC fibers are essential for designing microwave absorption and mechanical properties of multifunctional composites. In this study, SLF, KD-II and KD-S SiC fibers were used to fabricate SiC f /SiC composites. The SLF SiC fibers are composed by amorphous SiOC. The KD-II and KD-S SiC fibers exhibit higher crystallizations and free carbon content. The conductivity of SLF, KD-II and KD-S SiC fibers are 0.0127, 1.184 and 0.1316 S/cm, respectively. The flexural strength of SLF, KD-II and KD-S SiC f /SiC composites are 147.77, 322.57 and 248.16 MPa, respectively. The microwave absorption property of the SLF SiC f /SiC composites can be obtained over -25 dB with a thickness of 2.3 mm and the effective absorption bandwidth (EAB) below -10 dB reaches 3.72 GHz with the thickness of 2.7 mm. In contrast, the KD-II SiC f /SiC composites only reach -3.6 dB in the whole X band when the thickness varies from 2 to 2.9 mm. KD-S SiC f /SiC composites can be obtained over -9dB with the thickness of 2mm and the EAB below -7 dB reaches 4.12 GHz with a thickness of 2.2 mm. The mechanisms of mechanical, microwave absorption and penitential applications for SiC f /SiC composites are also discussed.

This work aimed to develop NASICON-type Li1.3Al0.3Ti1.7(PO4)3 (LATP) ceramic as a new type of high-temperature microwave absorption material. LATP ceramics were prepared by traditional solid-state reaction with sintering temperature ranging from 950 to 1100 °C for phase, microstructure, conductivity, dielectric property, and microwave absorption property study. Moreover, the dielectric property and microwave absorption property of LATP ceramic and NASICON-type Na3Zr2Si2PO12 (NZSP) ceramic in our previous work were compared. Results showed that LATP ceramic sintered at 1050 °C exhibited the highest conductivity of 2.43 × 10–4 S cm−1 and optimal microwave absorption property. The minimum reflection loss (RLmin) was − 13.4 dB at 11.14 GHz and the bandwidth (RL

Enhanced microwave absorption Ba0.4−xLaxCa0.6Fe11.4Co0.6O19 (BLCFCO, x = 0.0, 0.1, 0.2, 0.3, and 0.4) ceramics were prepared. The characteristics of the BLCFCO ceramics such as phase, microstructure, magnetic properties, electromagnetic properties, and reflection loss (RL) were investigated. The lanthanum-based substitution enhances the microwave absorption properties of the Ba0.4Ca0.6Fe11.4Co0.6O19 ceramics, and the RL values less than − 5 dB are obtained in 8.6–12.9 GHz with a thickness of 1.5 mm. A maximum RL with − 28.3 dB can be obtained at 10.6 GHz for the composites with x = 0.3. These results indicate that the Ba0.1La0.3Ca0.6Fe11.4Co0.6O19 ceramic developed with an effective, a thin, and wide-bandwidth absorption is highly promising materials for electromagnetic application.

The A-site substituted (20 mol% Sr2+ and Ca2+) and B-site substituted (20 mol% Co3+ and Mn3+) M-type BaFe12O19 (BFO) ceramics were synthesized and the magnetic properties and microwave absorption were investigated. The A-site substitution by Ca2+ or B-site substitution by Co3+ can effectively modify the magnetic properties of the M-type BFO. The B-site dopant suppresses the complex permittivity more greatly than A-site ones and substitution of Co3+ at B-site changes the microwave permeability response to a resonate-like manner in 2.6–18 GHz. The A-site substitution is more effective on the enhancement of peak absorption whilst B-site substitution is more effective on the enhancement of absorption bandwidth. A wide bandwidth of reflection loss (RL) value below − 5 dB (> 70% microwave absorption) of the BaFe11.8Mn0.2O19 ceramic is obtained in 3.6–18 GHz and the minimum RL of − 18.5 dB is obtained at 7.2 GHz with a thickness of 2.5 mm.