Deposition of a SiO2 Shell of Variable Thickness and Chemical Composition to Carbonyl Iron: Synthesis and Microwave Measurements
| Autor: | Dmitry Petrov, Andrey N. Lagarkov, S. N. Starostenko, Andrey S. Naboko, V. I. Polozov, P.A. Zezyulina, Sergey A. Maklakov, Alexey V. Osipov, Sergey S. Maklakov, Arthur V. Dolmatov |
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| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Permittivity
soft magnetic powder Materials science Scanning electron microscope Iron Shell (structure) 02 engineering and technology TP1-1185 engineering.material 010402 general chemistry 01 natural sciences Biochemistry Article Analytical Chemistry Magnetics Carbonyl iron Coating Paraffin wax Electrical and Electronic Engineering Microwaves Instrumentation Chemical composition protective coating Chemical technology Silicon Dioxide 021001 nanoscience & nanotechnology Atomic and Molecular Physics and Optics 0104 chemical sciences Chemical engineering microwave permittivity engineering core–shell particles 0210 nano-technology Layer (electronics) |
| Zdroj: | Sensors, Vol 21, Iss 4624, p 4624 (2021) Sensors Volume 21 Issue 14 Sensors (Basel, Switzerland) |
| ISSN: | 1424-8220 |
| Popis: | Protective SiO2 coating deposited to iron microparticles is highly demanded both for the chemical and magnetic performance of the latter. Hydrolysis of tetraethoxysilane is the crucial method for SiO2 deposition from a solution. The capabilities of this technique have not been thoroughly studied yet. Here, two factors were tested to affect the chemical composition and the thickness of the SiO2 shell. It was found that an increase in the hydrolysis reaction time thickened the SiO2 shell from 100 to 200 nm. Moreover, a decrease in the acidity of the reaction mixture not only thickened the shell but also varied the chemical composition from SiO3.0 to SiO8.6. The thickness and composition of the dielectric layer were studied by scanning electron microscopy and energy-dispersive X-ray analysis. Microwave permeability and permittivity of the SiO2-coated iron particles mixed with a paraffin wax matrix were measured by the coaxial line technique. An increase in thickness of the silica layer decreased the real quasi-static permittivity. The changes observed were shown to agree with the Maxwell Garnett effective medium theory. The new method developed to fine-tune the chemical properties of the protective SiO2 shell may be helpful for new magnetic biosensor designs as it allows for biocompatibility adjustment. |
| Databáze: | OpenAIRE |
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