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  1. نقش فاز پلیمری در بهبود عملکرد و جذب الکترومغناطیسی نانوکامپوزیت‌های فریت‌های اسپینل نیکل و کبالت
نقش فاز پلیمری در بهبود عملکرد و جذب الکترومغناطیسی نانوکامپوزیت‌های فریت‌های اسپینل نیکل و کبالت
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نقش فاز پلیمری در بهبود عملکرد و جذب الکترومغناطیسی نانوکامپوزیت‌های فریت‌های اسپینل نیکل و کبالت

خان احمدی صمغ آبادی، سیاوش Khanahmadi Samghabadi, Siavash

The Role of Polymeric phase in Enhancing the Performance and Electromagnetic Absorption of Nickel and Cobalt Spinel Ferrite Nanocomposites

Khanahmadi Samghabadi, Siavash | 2025

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 58436 (07)
  4. University: Sharif University of Technology
  5. Department: Materials Science and Engineering
  6. Advisor(s): Madaah Hoseini, Hamid Reza; Pircheraghi, Gholamreza
  7. Abstract:
  8. In light of the increasing challenges posed by electromagnetic interference in electronic and telecommunication systems, the development of high-performance microwave absorbers is of great importance. In this study, spinel ferrite-based nanocomposites of (CoxNi1-x)Fe2O4 were synthesized and investigated in several steps with the aim of improving electromagnetic wave absorption and magnetic properties. In the first stage, (CoxNi1-x)Fe2O4 nanoparticles were synthesized using the chemical co-precipitation method for various values of x (ranging from 0 to 1 in steps of 0.25). After determining the optimal composition at x = 0.75, the samples were prepared and examined at four different calcination temperatures (600, 700, 800, and 900 °C). The structural, morphological, magnetic, and absorptive parameters of the samples were analyzed and evaluated using XRD, FTIR, FE-SEM (EDS), DLS, EDS, VSM, and VNA tests, respectively. Subsequently, to improve the absorption performance and enhance physical properties, the optimized nanoparticles were coated with polyaniline. This process was carried out by an emulsion method at three different weight ratios (0.5, 1, and 1.5). The investigation of saturation magnetization and coercivity showed that the coated sample with a weight ratio of 0.5 exhibited a decrease in Ms (from 68 to 51 emu/g) and an increase in Hc (from 841 to 941 Oe). Microwave absorption tests also indicated a significant improvement in the absorptive performance of the nanocomposite after coating; while the pure sample (Co0.8Ni0.2)Fe2O4 demonstrated an absorption of −17 dB at 16.4 GHz with an effective bandwidth of 1.6 GHz and a matching thickness of 10.2 mm, the coated sample (Co0.8Ni0.2)Fe2O4/PANI exhibited an absorption of −18 dB at 16.4 GHz with an effective bandwidth of 4.2 GHz at a matching thickness of 5.2 mm. These results confirm that the addition of a conductive polymeric phase can lead to improved microwave absorption performance and magnetic properties, making the synthesized nanocomposite an efficient candidate in the field of electromagnetic absorbers
  9. Keywords:
  10. Spinel Ferrite ; Co-Precipitation Synthesis ; Chemical Precipitation ; Magnetic Properties ; Structure-Magnetic Property Correlation ; Electromagnetic Absorption

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