Ranu Pal; Sandeep Kumar Singh; M.J. Akhtar; Kamal K. Kar
Abstract
Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental ...
Read More
Efforts to use microwaves in material processing are gradually increasing. However, the phenomenon associated with the processing is less understood. The conversion of electromagnetic energy into heat depends largely on the dielectric properties of the material being treated. Therefore, the fundamental knowledge of these properties is essential for processing of materials using microwaves. In this study, first the dielectric evolution of silicon carbide (SiC) infused epoxy nanocomposites prepared at room temperature with 0-0.3 wt% content of SiC was measured. Secondly, the dielectric properties of the prepared nanocomposites after heating for 10 min in microwaves at a power of 500 W were investigated in order to see the effect of microwave curing. The dielectric properties of all the samples were measured at the microwave frequency of 2.45 GHz using the advanced cavity perturbation method attached to a vector Network Analyzer (VNA). The results indicate that the dielectric properties of the resultant nanocomposites increase with the increase in SiC content as compared to the neat epoxy sample. However, the dielectric properties were found to be decrease after microwave curing signaling the maximum possible extent of curing. This indicates that reinforcement of SiC nanoparticles in epoxy makes them ideal candidates for efficient microwave curing of nanocomposites. Lastly, the determination of thermal properties also confirms the maximum possible extent of curing of epoxy using SiC as nanofillers. Copyright © 2018 VBRI Press.
Vishal K. Chakradhary; Azizurrahaman Ansari; M.J. Akhtar
Abstract
Material synthesis is a scientific art, considering all parameters and conditions in practical view and applying them in an experiment. Properties of synthesized material can be tuned further by technically playing with concerned parameters individually. In this work, a one to one relation between the ...
Read More
Material synthesis is a scientific art, considering all parameters and conditions in practical view and applying them in an experiment. Properties of synthesized material can be tuned further by technically playing with concerned parameters individually. In this work, a one to one relation between the formation of cubic spinel ferrite structure with stable phase and morphology has been established, and corresponding changes in the magnetic properties are investigated with temperature. Heat treatment method is adopted for the preparation of nanoparticles of cobalt doped nickel ferrite Ni1-xCoxFe2O4 (x=0.5) and characterized by XRD, FESEM, TGA and VSM. Initially, as synthesized powder sample shows amorphous and weak ferromagnetic nature (Ms = 0.04 emu/g, Hc = 92.42 Oe), but heat treatment at 400ºC exhibits signature of phase formation with irregular particle shape and ferromagnetic (Ms = 6.62emu/g, Hc = 460 Oe) behaviour. On further heating upto 600ºC, the nanoparticles of Ni1-xCoxFe2O4 (x=0.5) is formed with stable cubic spinel crystal structure (lattice constant a=8.35452Å) and enhanced magnetic properties (Ms=8.24emu/g, Hc=1955Oe). Due to higher coercivity obtained of Ni1-xCoxFe2O4 (x=0.5) nanoparticles, it may be useful material in the production of data storage devices, permanent magnet, parts of electronic circuits and also in stealth technology.
