Research on magnetic and microwave absorbing properties of Co2Y ferrite fabricated by sol–gel process

La1-xCaxMnO3(0≤x≤0.5) with perovskite-type structure has been successfully prepared by sol-gel method as a microwave and infrared multi-functional material. The effects of Ca incorporation on the stucture, electrical conductivity, infrared emissivity and microwave-absorbing properties were investigated in detail by XRD, 4-point probes resistivity measurement system,IR-2 infrared-emissivity analyzer and vector network analyzer. XRD results show that the perovskite structure of LaMnO3 is hardly changed when the doping concentration (x) of Ca2+ is less than or equal to 0.5. The incorporation of Ca in LaMnO3 leads to the decrease of electrical conductivity, while the infrared emissivities are decreased. Moreover, microwave-absorbing properties in the frequency range of 2-18 GHz are sensitive to Ca content. The optimal reflection loss calculated from the measured permittivity and permeability is 42 dB at 10.5 GHz with a thickness of 2.0 mm when the doping amount of Ca2+ is 0.1. It is possible to make Ca-doped lanthanum manganites achieve compatible camouflage capability for radar and infrared wave-band.

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Preparation and microwave absorbing properties of polyaniline/NiFe2O4/graphite nanosheet composites via sol–gel reaction and in situ polymerization

Journal of Sol-Gel Science and Technology ◽

10.1007/s10971-016-4226-6 ◽

2016 ◽

Vol 81 (3) ◽

pp. 824-830 ◽

Cited By ~ 16

Author(s):

Xingliang Chen ◽

Shuhua Qi

Keyword(s):

In Situ Polymerization ◽

Sol Gel ◽

Microwave Absorbing Properties ◽

Graphite Nanosheet ◽

Microwave Absorbing

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Microwave Absorption of BaLa0.5Fe11.5O19/SiO2 Nano-Powders

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.105-106.380 ◽

2010 ◽

Vol 105-106 ◽

pp. 380-382

Author(s):

Zhi Dong Han ◽

Qing Rui Zhao ◽

Li Min Dong ◽

Ze Wu ◽

Xian You Zhang

Keyword(s):

Sol Gel ◽

Sio2 Nanoparticles ◽

Nano Particles ◽

Powder Size ◽

X Ray Diffraction ◽

Microwave Absorbing Properties ◽

Diffraction Peaks ◽

Microwave Absorbing ◽

Xrd Patterns ◽

Nano Size

Nano-size BaM hexaferrites (BaLa0.5Fe11.5O19) were synthesized in the presence of SiO2 nano- particles by sol-gel method. The X-ray diffraction (XRD) patterns of ferrites annealed at above 900°C manifested that all the species had hexagonal crystal structure and no diffraction peaks of SiO2 found. Compared with BaLa0.5Fe11.5O19 powders, those synthesized in the presence of SiO2 nano-particles presented in smaller powder size, as proved by scanning electron microscopy (SEM). As a result, SiO2 nanoparticles promoted the formation of more homogeneous and finer ferrite crystal while the structure of hexaferrites consisted with that synthesized without SiO2 nano-particles. Microwave absorbing properties were evaluated. As a result, BaLa0.5Fe11.5O19/SiO2 showed good microwave absorbing properties with the maximum absorption more than 20dB.

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The crystallization of thin-film ceramics

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100122095 ◽

1992 ◽

Vol 50 (1) ◽

pp. 338-339

Author(s):

J.M. Schwartz ◽

L.F. Francis ◽

L.D. Schmidt ◽

P.S. Schabes-Retchkiman

Keyword(s):

Thin Films ◽

Grain Size ◽

Sol Gel ◽

Processing Route ◽

Small Areas ◽

Ceramic Thin Films ◽

Complex Shapes ◽

Sol Gel Process ◽

Ceramic Precursors ◽

Crystalline Ceramic

Ceramic thin films and coatings are of interest for electrical, optical, magnetic and thermal barrier applications. Critical for improved properties in thin films is the development of specific microstructures during processing. To this end, the sol-gel method is advantageous as a versatile processing route. The sol-gel process involves depositing a solution containing metalorganic or colloidal ceramic precursors onto a substrate and heating the deposited layer to form a crystalline or non-crystalline ceramic coating. This route has several advantages, including the ability to create tailored microstructures and properties, to coat large or small areas, simple or complex shapes, and to more easily prepare multicomponent ceramics. Sol-gel derived coatings are amorphous in the as-deposited state and develop their crystalline structure and microstructure during heat-treatment. We are particularly interested in studying the amorphous to crystalline transformation, because many key features of the microstructure such as grain size and grain size distribution may be linked to this transformation.

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