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Dolmatov AV, Maklakov SS, Artemova AV, Petrov DA, Shiryaev AO, Lagarkov AN. Deposition of Thick SiO 2 Coatings to Carbonyl Iron Microparticles for Thermal Stability and Microwave Performance. SENSORS (BASEL, SWITZERLAND) 2023; 23:1727. [PMID: 36772763 PMCID: PMC9919206 DOI: 10.3390/s23031727] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 01/23/2023] [Accepted: 02/01/2023] [Indexed: 06/18/2023]
Abstract
Thick dielectric SiO2 shells on the surface of iron particles enhance the thermal and electrodynamic parameters of the iron. A technique to deposit thick, 500-nm, SiO2 shell to the surface of carbonyl iron (CI) particles was developed. The method consists of repeated deposition of SiO2 particles with air drying between iterations. This method allows to obtain thick dielectric shells up to 475 nm on individual CI particles. The paper shows that a thick SiO2 protective layer reduces the permittivity of the 'Fe-SiO2-paraffin' composite in accordance with the Maxwell Garnett medium theory. The protective shell increases the thermal stability of iron, when heated in air, by shifting the transition temperature to the higher oxide. The particle size, the thickness of the SiO2 shells, and the elemental analysis of the samples were studied using a scanning electron microscope. A coaxial waveguide and the Nicholson-Ross technique were used to measure microwave permeability and permittivity of the samples. A vibrating-sample magnetometer (VSM) was used to measure the magnetostatic data. A synchronous thermal analysis was applied to measure the thermal stability of the coated iron particles. The developed samples can be applied for electromagnetic compatibility problems, as well as the active material for various types of sensors.
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Dolmatov AV, Maklakov SS, Zezyulina PA, Osipov AV, Petrov DA, Naboko AS, Polozov VI, Maklakov SA, Starostenko SN, Lagarkov AN. Deposition of a SiO 2 Shell of Variable Thickness and Chemical Composition to Carbonyl Iron: Synthesis and Microwave Measurements. SENSORS (BASEL, SWITZERLAND) 2021; 21:4624. [PMID: 34300364 PMCID: PMC8309671 DOI: 10.3390/s21144624] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 07/01/2021] [Accepted: 07/02/2021] [Indexed: 11/17/2022]
Abstract
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.
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Affiliation(s)
- Arthur V. Dolmatov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
- Moscow Institute of Physics and Technology, National Research University, 9 Institutskiy per., 141700 Dolgoprudny, Russia
| | - Sergey S. Maklakov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Polina A. Zezyulina
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Alexey V. Osipov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Dmitry A. Petrov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Andrey S. Naboko
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Viktor I. Polozov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
- Moscow Institute of Physics and Technology, National Research University, 9 Institutskiy per., 141700 Dolgoprudny, Russia
| | - Sergey A. Maklakov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Sergey N. Starostenko
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
| | - Andrey N. Lagarkov
- Institute for Theoretical and Applied Electromagnetics RAS, Izhorskaya St. 13, 125412 Moscow, Russia; (A.V.D.); (P.A.Z.); (A.V.O.); (D.A.P.); (A.S.N.); (V.I.P.); (S.A.M.); (S.N.S.); (A.N.L.)
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Photocatalysis: Activity of Nanomaterials. Catalysts 2021. [DOI: 10.3390/catal11050611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Photocatalytic processes have shown great potential as a low-cost, green-chemical, and sustainable technology able to address energy and environmental issues [...]
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