Facile Preparation and Electromagnetic Properties of Core−Shell Composite Spheres Composed of Aloe-like Nickel Flowers Assembled on Hollow Glass Spheres

Abstract

Aloe-like nickel flowers assembled on hollow glass spheres are successfully synthesized by a facile low-temperature hydrothermal reduction process, and thus novel 3D core−shell composite hollow spheres with hierarchical structures are fabricated. By properly tuning the process conditions and the component of the reaction solution, a series of composite spheres with gradient in morphologies of the shell layer can be prepared. On the basis of a series of contrast experiments, the probable formation mechanism of the core−shell hierarchical structures is proposed. The magnetic properties of the products are studied, and the results demonstrate that the composite spheres present ferromagnetic properties related to the special microstructures. Because of the conductive and ferromagnetic behavior of the nickel shells, the composite spheres possess morphology-dependent microwave absorption properties and may have some promising applications in low-density magnetic materials and microwave absorbers. This work provides an additional strategy to prepared core−shell composite spheres with tailored shell morphology and electromagnetic properties.

Preparation and microwave absorption properties of basalt fiber/nickel core–shell heterostructures

“…R L of sample C is in the range of 5.3-7.9 dB in the whole frequency investigated. However, R L of sample B is more than 15 dB in the whole X band and reaches 40 dB at 8.9 GHz, which is better than or comparable to those of CNT/Fe nanocomposites [24,25], Fe 3 O 4 /SnO 2 core/shell nanorods [27], hollow glass spheres/nickel core/shell composite [39] and Ni/C nanocapsules [40]. The excellent microwave absorption properties of basalt fiber/nickel core-shell heterostructures are attributed to the effective complementarities between the dielectric loss and the magnetic loss as described above.…”

Microwave Absorption Properties of Fe-Doped Ordered Mesoporous Carbon (CMK-3)/Silica Matrix Nanocomposites with Magnetic Multi-Resonance Mechanisms

“…It is well known that EM wave absorbing/shielding materials have been famously testi¯ed in that unnecessary EM signals will be absorbed by these kinds of products as soon as possible. [1][2][3][4] That is to say, to the greatest extent, the incent EM waves will be more absorbed and little re°ected as well as¯nally converted into heat energy with all aspects of applications, such as stealth¯ghting aircrafts, warships etc., during the process of absorbtion. Though a considerable number of works about this issue have been completed by scienti¯c researchers, yet an ideal target seeking for light-weight, high-e±cient, little-density and wide-bandwidth in absorbers is not preferably solved.…”

Controlled Synthesis and Microwave Absorption Property of Chain-Like Co Flower

“…The microwave absorbing material has received extensive attention due to their prospective application in electromagnetic shielding coatings, microwave darkrooms, and self-concealing weapons in industry, commerce, and military affairs [1]–[3]. The conventional electromagnetic loss mechanisms are magnetic loss and dielectric loss, so most of microwave absorbers are composed of magnetic and dielectric materials.…”