Currently, the microwave absorbers usually suffer dreadful electromagnetic wave absorption (EMWA) performance damping at elevated temperature due to impedance mismatching induced by increased conduction loss. Consequently, the development of high-performance EMWA materials with good impedance matching and strong loss ability in wide temperature spectrum has emerged as a top priority. Herein, due to the high melting point, good electrical conductivity, excellent environmental stability, EM coupling effect, and abundant interfaces of titanium nitride (TiN) nanotubes, they were designed based on the controlling kinetic diffusion procedure and Ostwald ripening process. Benefiting from boosted heterogeneous interfaces between TiN nanotubes and polydimethylsiloxane (PDMS), enhanced polarization loss relaxations were created, which could not only improve the depletion efficiency of EMWA, but also contribute to the optimized impedance matching at elevated temperature. Therefore, the TiN nanotubes/PDMS composite showed excellent EMWA performances at varied temperature (298–573 K), while achieved an effective absorption bandwidth (EAB) value of 3.23 GHz and a minimum reflection loss (RLmin) value of − 44.15 dB at 423 K. This study not only clarifies the relationship between dielectric loss capacity (conduction loss and polarization loss) and temperature, but also breaks new ground for EM absorbers in wide temperature spectrum based on interface engineering.

Simultaneous development of well impedance matching and strong loss capability has become a mainstream method for achieving outstanding electromagnetic microwave absorption (EMWA) performances over wide temperature range. However, it is difficult to pursue both due to the mutual restraint of relationship between impedance matching and loss capability about temperature. Here, we propose a flexible regulation engineering of titanium nitride (TiN) nanofibrous membranes (NMs, TNMs), which could be distributed uniformly in the polydimethylsiloxane (PDMS) matrix and contributed to the formation of abundant local conductive networks, generating the local conductive loss and enhancing the loss ability of EMWs. Moreover, when the TNMs are used as functional units and dispersed in the matrix, the corresponding composites exhibit an outstanding anti-reflection effect on microwaves. As hoped, under the precondition of good impedance matching, local conductive loss and polarization loss together improve the loss capacity at room temperature, and polarization loss can compensate the local conductive loss to acquire effective dielectric response at elevated temperature. Benefiting from the reasonably synergistic loss ability caused by flexible regulation engineering, the corresponding composites exhibit the perfect EMWA performances in a wide temperature range from 298 to 573 K. This work not only elaborates the ponderable insights of independent membrane in the composition-structure-function connection, but also provides a feasible tactic for resolving coexistence of well impedance matching and strong loss capability issues in wide temperature spectrum.

Dielectric ceramics composites are potential high-temperature microwave absorption materials (MAMs), and the critical challenge is to achieve high-efficiency and temperature insensitive absorption characteristics suitable for wide temperature and frequency range. Herein, the electromagnetic attenuation properties of TiN/ Fe2Ni2N/SiO2 composites are studied in detail. The magnetic ceramic composites proposed exhibited stable attenuation behaviors at a wide temperature range (293-873 K). Notably, the optimal reflection loss (RL) value had reached -32.4 dB with a thickness of 2.8 mm at 373 K, and the effective absorption bandwidth (EAB) covered 3.89 GHz at 873 K. The excellent high-temperature attenuation capacity is attributed to the balancing strategy of dielectric and magnetic losses, as well as multiple polarization loss behaviors. The results showed that introducing magnetic components to form magnetic ceramic composites might shed light on the development of the TiN ceramic family for promising MAMs at a wide temperature range. (C) 2022 Published by Elsevier B.V.

With the increasing advance of fifth generation (5G) network and the gradual expansion of digital devices, harsh working environment for electronic devices has spawned higher requirements for microwave absorbing materials (MAMs). Since both the electromagnetic response and energy conversion character vary with temperature, to achieve temperature insensitive microwave absorption behaviour in wide temperature range has become extremely challenging. In this work, structured metacomposites containing sub-wavelength reduced graphene oxide (RGO)@carbon spheres were fabricated, and the microwave absorption was further improved through structural and composition design of the RGO@carbon units. Due to the unique anti-reflection effect on microwave of the metacomposites, the temperature-insensitive electromagnetic performance at elevated temperature could be exhibited. Moreover, both the dielectric relaxation behaviour and microwave absorption proformance of the system could be further increased. As a result, the effective absorption bandwidth (reflection loss (RL) < −10 dB) of the metacomposites with only 3.0 wt.% filler content could cover the entire X-band (8.2–12.4 GHz) frequency ranging from 298 to 473K. The metacomposite proposed in this work provides a “de-correlating” strategy to break the linkage between microwave absorption behaviour and temperature, which offers an interesting plateau for fabricating efficient high-temperature microwave absorption structures with tunable and designable advantages.

High-efficiency and temperature-insensitive microwave absorbing materials(MAMs)are ideal for high-temperature electromagnetic attenuation.Herein,the titanium nitride/boron nitride(TiN/BN)composite with TiN as the loss unit and BN as the impedance matching unit has been constructed by the in-situ synthesis method.The insulating BN not only effectively regulates and optimizes the conductivity and impedance matching of the material but also imparts steady cyclic microwave absorption properties.The steady dielectric loss ensures that TiN/BN composite has robust high-temperature absorption properties at X-band,with a minimum reflection loss(RLmin)of-16.74 dB at 873 K and an effective absorption band-width(EAB)of 3.26 GHz in the temperature range of 293-873 K.Compared with the TiN/SiO2 absorbers with a single system,the TiN/BN/SiO2 composite keeps reliable high temperature absorbing properties at 873 K.This work confirms that wave-transparent materials for dielectric property modulation can resolve poor temperature stability of effective absorption and non-reusability for high-temperature absorbing ma-terials,providing inspirations for designing efficiency high-temperature microwave absorbers.

The rational structure-effect relationship design of microwave absorption devices provides tremendous potential for the elimination of electromagnetic radiation contamination. Here, we report on the efficient microwave absorbers (MA) consisting of TiN/Fe2Ni2N nanoribbons (NRs) and nanoparticles (NPs) as a functional MA filler. The cross-linked network and multiple heterogeneous interface polarization of TiN/Fe2Ni2N NRs contributes to improved conductance loss and polarization loss and is favorable for obtaining the lightweight MA absorber at a low filler content of 15 wt%. As a comparison, due to the enhanced permeability and balanced permittivity, the maximum reflection loss of the NPs filled absorber can reach -31.9 dB at a filler thickness of 1.3 mm at a high filler content of 50 wt%. This work deepens the understanding for designing the high-performance MA through tuning and optimizing the dielectric and magnetic loss.

In this work, black titanium monoxide (TiO) nanoparticles were synthesized by hydrogen assisted magnesium thermal reduction method from nanotube titanic acid (NTA) and their electromagnetic properties were investigated. The black TiO nanoparticles exhibited the optimal reflection loss of-37.7 dB at a thin absorbance layer of 1.2 mm in thickness, which showing a promising candidate in electromagnetic wave absorbing (EA). To explore the mechanism of EA, TiO nanoparticles prepared from the other two initiators (commercial grade TiO and P25 titanium dioxide) was used as a comparison. The results show that the crystalline structure and microscopic defects, which arouse from the formation of TiO in the hydrogen assisted process, affect the electromagnetic performance of Ti-O binary system significantly in addition to their intrinsic effects. We hope this study help to open a new way for the designing of highperformance EA materials. (c) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.