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Carbon-coated Fe3O4 core-shell super-paramagnetic nanoparticle-based ferrofluid for heat transfer applications
Mohd Imran1, Nasser Zouli1, Tansir Ahamad2
1Department of Chemical Engineering, Faculty of Engineering, Jazan University P.O. Box. 706 Jazan 45142 Saudi Arabia.
Nanoscale Advances
|September 22, 2022
Summary
This study demonstrates significant enhancements in electrical and thermal conductivity using iron oxide (Fe3O4) and carbon-coated Fe3O4 core-shell nanoparticles in ferrofluids. These findings offer improved material properties for advanced applications.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Ferrofluids based on iron oxide nanoparticles (NPs) are crucial for various applications.
- Investigating the electrical and thermal conductivity of these ferrofluids is essential for optimizing their performance.
- Carbon coating can modify the properties of magnetic nanoparticles.
Purpose of the Study:
- To synthesize and characterize Fe3O4 and Fe3O4@carbon (Fe3O4@C) core-shell nanoparticles (NPs).
- To investigate the electrical and thermal conductivity of ferrofluids based on these NPs.
- To compare the conductivity enhancements with existing material systems and theoretical models.
Main Methods:
- Fe3O4 NPs synthesized via chemical co-precipitation.
- Carbon coating applied using the hydrothermal technique.
- Electrical and thermal conductivity measured for ferrofluids with varying NP concentrations and sizes.
- Magnetic characterization to confirm superparamagnetic behavior.
Main Results:
- Synthesized Fe3O4 NPs (∼5-25 nm) and Fe3O4@C NPs (∼7-28 nm) with carbon shell thickness of ∼1-3 nm.
- Superparamagnetic behavior observed for small average-sized Fe3O4 and Fe3O4@C NPs.
- Exceptional electrical conductivity enhancement: up to ~3222% for Fe3O4 NPs and ~2015% for Fe3O4@C NPs.
- Significant thermal conductivity enhancement: ~153% for Fe3O4 NPs and ~116% for Fe3O4@C NPs.
- Higher thermal conductivity in bare Fe3O4 NP ferrofluids attributed to chain-like network formation.
Conclusions:
- Fe3O4 and Fe3O4@C core-shell NPs significantly enhance electrical and thermal conductivity in ferrofluids.
- Bare Fe3O4 NPs showed superior thermal conductivity enhancement due to network formation.
- Experimental results align with the Maxwell effective model and surpass previously reported data.
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