| Abstract [eng] |
Nowadays, technology is expanding very fast. This is one of the main reasons why more and more research is being carried out on a variety of substances with specific properties and characteristics. One such material is coal. The physical parameters of its various composites differ significantly from those of other materials. That is why there is so much interest in coal. Polymer composites with carbon nanoparticles have attracted a great deal of attention. Carbon nanotubes (CNTs) are distinctive for their physical and structural properties and have many prospects for the production of new materials. One of the many materials that are associated with carbon is carbon-coated nickel nanoparticles Ni @ C. Nickel (Ni) nanoparticles and carbon-coated Ni nanoparticles have superparamagnetic or ferromagnetic properties that make them promising in the design of microwave absorbing devices due to magnetic loss. In this area of scientific interest, low-frequency noise spectroscopy can be applied as an information method to investigate the conductance mechanisms of charge carriers in new materials. The aim of this study was to investigate the low-frequency noise characteristics of composites and charge transfer mechanisms with a binding matrix of epoxy resin and a filler of Ni @ C and Multiwalled Carbon nanotubes (MWCNT) in the frequency range of 10 Hz to 20 Hz and temperature range of 75 K to 380 K. The low frequency characteristics and charge transfer mechanisms of composites were investigated. In the studied frequency range, the electrical fluctuation spectra of composite materials with MWCNT and Ni @ C nanoparticles are almost always 1 / fa type. These noises are due to the superposition of Motto’s jumps and carrier capture and release processes. Minimal components of generational - recombinant (GR) noise caused by deep carrier capture centers were also observed in the samples at low voltages. In the study of the temperature characteristics of the samples, it was observed that thermally activated tunneling takes place in the low temperature range of 75 - 180 K samples with 0.09% vol MWCNT + 0.2% vol. It has also been observed from the Mott's approximation that in samples with 0.09% vol MWCNT + 0.2% vol Ni @ C the percolation network consists mainly of Ni @ C particles. |
