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Projects / Programmes source: ARIS

Synthesis of magnetic nanoparticles for the microwave absorbers and magnetic fluids

Research activity

Code Science Field Subfield
2.04.00  Engineering sciences and technologies  Materials science and technology   

Code Science Field
T153  Technological sciences  Ceramic materials and powders 
Keywords
synthesis of nanoparticles, ferrites, microvawe materials, nanocomposites, magnetic fluids
Evaluation (rules)
source: COBISS
Researchers (16)
no. Code Name and surname Research area Role Period No. of publicationsNo. of publications
1.  27839  PhD Tanja Botić  Systems and cybernetics  Researcher  2009  73 
2.  19411  PhD Vladimir Boštjan Bregar  Materials science and technology  Researcher  2007 - 2009  105 
3.  28207  Boštjan Denac    Technical associate  2007 - 2008  18 
4.  28223  PhD Ana Drmota Petrič  Chemical engineering  Junior researcher  2007 - 2009  28 
5.  01360  PhD Mihael Drofenik  Chemistry  Researcher  2007 - 2009  770 
6.  30163  Gregor Ferk  Chemical engineering  Researcher  2009  49 
7.  05958  PhD Darko Hanžel  Physics  Researcher  2007 - 2009  177 
8.  15148  PhD Darja Lisjak  Materials science and technology  Researcher  2007 - 2009  414 
9.  10372  PhD Darko Makovec  Materials science and technology  Head  2007 - 2009  667 
10.  28943  Simon Medved  Electronic components and technologies  Researcher  2007 - 2009 
11.  05616  Bogo Miklavčič  Electronic components and technologies  Researcher  2007 - 2009 
12.  19271  PhD Darja Pečar  Chemical engineering  Researcher  2007 - 2008  319 
13.  15599  Tomislav Pustotnik    Technical associate  2008 - 2009 
14.  10727  PhD Mojca Slemnik  Chemistry  Researcher  2007 - 2008  119 
15.  12025  MSc Peter Tarman  Mechanics  Researcher  2007 - 2009  22 
16.  10019  PhD Andrej Žnidaršič  Electronic components and technologies  Researcher  2007 - 2009  206 
Organisations (2)
no. Code Research organisation City Registration number No. of publicationsNo. of publications
1.  0106  Jožef Stefan Institute  Ljubljana  5051606000  91,005 
2.  0794  University of Maribor, Faculty of Chemistry and Chemical Engineering  Maribor  5089638012  13,075 
Abstract
The project is concerned with investigation, which will lead to the syntheses of nanoparticles of barium hexaferrite, one of technically most attractive magnetic materials, which can be applied in magnetic fluids and microwave absorbers. The syntheses route will be developed via the controlled hydrothermal process governed by the basic theory of crystallization, which strictly separates the nucleation from the particle growth process. The synthesized magnetic nanoparticles will be used to prepare magnetic nanocomposites for the absorption of electromagnetic radiation and for magnetic fluids.
Significance for science
In the project, ultrafine, superparamagnetic nanoparticles of barium hexaferrite were hydrothermally synthesized together with their stable suspensions, i.e., ferrofluids, for the first time. A broad knowledge related to the processes responsible for the control of the particle size during the hydrothermal synthesis has been developed. Research of the mechanisms that enable the decrease of the hexaferrite formation temperature prove to be of crucial importance. The developed knowledge enabled us to be the first in the world to synthesize hexaferrite using simple co-precipitation. Secondary re-crystallization also has an important influence on the particle growth during synthesis. In this project the method was developed, which enables complete blocking of the secondary re-crystallization. The method based on the adsorption of oleic acid onto the synthesized nanoparticles is general and can also be applied in the hydrothermal synthesis of other materials. The synthesis of the ultrafine hexaferrite nanoparticles enabled a study of the adaptation of the material’s crystal structure and the magnetic properties to their very small size (size effect). Both effects are of fundamental importance for the development of nanoscience. As the nanoparticles’ size decrease to reach the dimensions of a few cell parameters of their crystal structure, their structure changes significantly, which also influences the properties. This effect has been intensively studied in the case of ferrites with a simple, cubic-spinel structure. For the basic science, also the research on the influence of the size effect on the complex, layered structure of hexaferrite would be of great interest. The thickness of the disc-like nanoparticles synthesized in the framework of this project barely exceeds one cell parameter of their structure and makes them very interesting for a study of the size effect. In the framework of the project, some of the basic influences of their properties have been explained. However, we believe that the possibility of synthesizing appropriate nanoparticles will trigger further research. The project contributed to the development of new knowledge regarding the characterization of nanomaterials. In the research on the structural properties of the nanoparticles some sophisticated methods were used, including high-resolution electron microscopy, X-ray diffractometry, and Mossbauer spectroscopy. In the characterisation of the ultrafine nanoparticles, these methods are at the cutting edge. The characterization therefore required the development of new knowledge . Special attention was given to the development of the knowledge related to the preparation of stable suspensions of the barium hexaferrite nanoparticles in different carrier liquids, i.e., ferrofluids. Ferrofluids have numerous applications in technology and, recently, especially in medicine. In addition, ferrofluids are important as precursors for the syntheses of different magnetic nanocomposite materials. It is expected that our new ferrofluids will be particularly important in the preparation of a number of new nanostructured materials, for example, nanocomposite materials containing nanoparticles dispersed in solid matrixes of a polymer or silica. In this project, the nanocomposite containing a large content of nanoparticles in a methyl methacrylate matrix was prepared. Stable suspensions are also needed for the deposition of nanoparticle layers onto different substrates, for example, with electrophoresis. In the framework of the project the original method for the preparation of the ferrofluids using the hydrothermal method was developed. The method is based on the synthesis of nanoparticles in the presence of oleic acid as a surfactant. The method is general and appropriate for the preparation of ferrofluids of different materials. For example, the method was already successfully applied in the preparation of ferrofluids based on cobalt-ferrite nanoparticles.
Significance for the country
The synthesis of superparamagnetic, barium-hexaferrite nanoparticles and their stable suspensions, so-called ferrofluids, represents a possible foundation for the development of different new materials, especially nanocomposite materials containing magnetic nanoparticles dispersed in different solid matrixes or deposited onto different substrates. New materials can represent new products with a lot of added value for Slovenian industry. All the procedures developed for the syntheses of nanoparticles and ferrofluids enable a rapid transfer to mass production. One of the possible applications of hexaferrite-containing polymer nanocomposites is in absorbers for the protection of humans and devices against electromagnetic radiation at high frequencies. Thus, the knowledge developed in the framework of this project will not only contribute to the development of new products in Slovenia, but will also be of general importance for the protection against electromagnetic radiation.
Most important scientific results Annual report 2008, final report, complete report on dLib.si
Most important socioeconomically and culturally relevant results Annual report 2008, final report, complete report on dLib.si
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