MOSCOW , 9 Mar. NCFU scientists have discovered patterns that can be used to create intelligent heat exchange systems. According to them, using a magnetic field, it is possible to influence the microstructure of a composite material. This leads to a change in its ability to conduct heat. The results of the study are published in Chemical Physics Letters.
A composite is a multi-component material made from two or more components with different physical and/or chemical properties that, when combined, result in a new material with characteristics different from those of the individual components and not the result of their simple addition.
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Scientists from the North Caucasian Federal University (NCFU) have studied a composite in which microparticles with high thermal conductivity are distributed in a medium with a low ability to conduct heat.
value in the material, a continuous trajectory of heat flow is formed, that is, there is a percolation effect and a sharp change in the properties of the material, in this case, thermal conductivity.
As explained at the university, in physics and chemistry, percolation is the phenomenon of the flow or non-flow of substances through materials. A good example of the process is the preparation of filter coffee when water flows through ground beans. » data-crop-width=»600″ data-crop-height=»400″ data-source-sid=»not_rian_photo» class=»lazyload» width=»1920″ height=»1280″ decoding=»async» />
In order to create the percolation effect, NCFU scientists in their study changed the structure of composites using a magnetic field.
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“In addition to heat-conducting graphite microparticles, the composite under study also contains magnetic nanoparticles. We acted on the material with a magnetic field from the outside. As a result, the nanoparticles ordered the graphite particles, and the effect we needed took place,” said Artur Zakinyan, head of the Department of Theoretical and Mathematical Physics of the NCFU.
By varying the parameters of the magnetic field, it is possible to change the thermal conductivity of the medium, he added. Studies have shown that the magnetic field has the greatest effect when the concentration of graphite particles is above the percolation threshold. one object to another (for example, coolant in radiators).
Unlike a material with fixed properties (for example, water), properties can be modified in intelligent environments, experts explained. To change the intensity of heat dissipation, it is not necessary to change the conductive material. It is enough to influence the magnetic field, which causes structural changes in it. This will allow to control the intensity of heat transfer, the scientists said.
The authors will continue to study how the modification of the structure can affect the change in various characteristics of such composite materials.