Structural Engineering Enabled Bimetallic (Ti_1‐yNb_y)₂AlC Solid Solution Structure for Efficient Electromagnetic Wave Absorption in Gigahertz

Abstract

Microstructures play a critical role to influence the polarization behavior of dielectric materials, which determines the electromagnetic response ability in gigahertz. However, the relationship between them, especially in the solid‐solution structures is still absent. Herein, a series of (Ti1‐yNby)2AlC MAX phase solid solutions with nano‐laminated structures have been employed to illuminate the aforementioned problem. The relationship has been investigated by the lattice distortion constructed via tuning the composition from Ti to Nb in the M‐site atomic layer. Experimental characterizations indicated that the dielectric response behaviors between declined conduction loss and boosted polarization loss can be well balanced by niobium atom manipulative solid‐solution engineering, which is conducive to impedance matching and electromagnetic absorption performance. Theoretical calculation further proved that the origin of electric dipoles is ascribed to the charge density differences resulting from the altered microscopic atomic distribution. As a result, the Ti1.2Nb0.8AlC exhibits the mostly optimized microwave absorption property, in which a minimum reflection loss of −42 dB and an effective absorption bandwidth of 4.3 GHz under an ultra‐thin thickness of 1.4 mm can be obtained. This work provides insight into the structural engineering in modifying electromagnetic response performance at gigahertz and which can be expanded to other solid‐solution materials.

Optimizing dielectric polarization for electromagnetic wave attenuation via an enhanced Maxwell–Wagner–Sillars effect in hollow carbon microspheres

“…RCS is the reflected intensity of the electromagnetic wave signal when the objects are irradiated by the detection radar. 64 In other words, when the detection objects cover the absorber layer, the smaller the reflected signal intensity, the stronger the attenuation capability to the irradiated electromagnetic energy. The model included the absorbers as the absorption layer and a perfect electric conductor (PEC) substrate as the reflected layer, and the incident EMW was irradiated along the negative direction of the Z -axis (eqn (S6)†).…”

Enhanced Polarization Loss toward Lanthanum–Samarium Doping-Encoded Defect Genes of Ferrite for Optimizing Microwave Absorption

“…Furthermore, the 1/4 wavelength offset mechanism and impedance matching can explain the MA mechanism, including the location and intensity of the reflection loss peak, if the absorber thickness ( t m ) at the absorption peak frequency ( f m ) satisfies the following equation t m = n λ 4 = n c f 4 m false| ε normalr μ normalr false| ( n = 1 , 3 , 5 , . . . ) where c is the speed of light in free space, |μ r | and |ε r | are the moduli of μ r and ε r , respectively, and the incident and reflected waves in the absorber differ by 180°, resulting in the disappearance of each other at the air absorber interface. Furthermore, the radar cross section (RCS) can be calculated through the equation σ .25em ( normald normalB normalm 2 ) = 10 .25em log true[ 4 π S λ 2 true| E normals E i true| 2 true] where S is the area of the simulated plate, λ is the wavelength of the incident EM wave, E s is the electric field intensity of transmitting waves, and E i is the electric field intensity of receiving waves.…”

Bimetallic solid solution MAX phase Ti2NbAlC2 as saturable absorber for passively Q-switched Er3+-doped fiber laser

“…The properties of MAX phase can be further tailor by forming bimetallic solid solution MAX phase on M-site. For instance, dissolving heteroatom in Msite can tune the electric property of MAX phase, since the d-electrons of M-site chemistry dominates the conductivity of MAX phase [28]. To date, numerous bimetallic solid solution MAX phase materials have been synthesized and studied.…”