Bahgata, M., Khedr, M., El Rouby, W. (2008). KINETICS AND MECHANISMS OF NANOCRYSTALLINE MGFE2O4/ CUFE2O4 CORE/SHELL REDUCTION IN FLOWING HYDROGEN AT 400–700 OC. test, 4(4th International Conference On Chemical & Environmental Engineering), 83-100. doi: 10.21608/iccee.2008.38377
M. Bahgata; M. H. Khedr; W. M.A. El Rouby. "KINETICS AND MECHANISMS OF NANOCRYSTALLINE MGFE2O4/ CUFE2O4 CORE/SHELL REDUCTION IN FLOWING HYDROGEN AT 400–700 OC". test, 4, 4th International Conference On Chemical & Environmental Engineering, 2008, 83-100. doi: 10.21608/iccee.2008.38377
Bahgata, M., Khedr, M., El Rouby, W. (2008). 'KINETICS AND MECHANISMS OF NANOCRYSTALLINE MGFE2O4/ CUFE2O4 CORE/SHELL REDUCTION IN FLOWING HYDROGEN AT 400–700 OC', test, 4(4th International Conference On Chemical & Environmental Engineering), pp. 83-100. doi: 10.21608/iccee.2008.38377
Bahgata, M., Khedr, M., El Rouby, W. KINETICS AND MECHANISMS OF NANOCRYSTALLINE MGFE2O4/ CUFE2O4 CORE/SHELL REDUCTION IN FLOWING HYDROGEN AT 400–700 OC. test, 2008; 4(4th International Conference On Chemical & Environmental Engineering): 83-100. doi: 10.21608/iccee.2008.38377

KINETICS AND MECHANISMS OF NANOCRYSTALLINE MGFE2O4/ CUFE2O4 CORE/SHELL REDUCTION IN FLOWING HYDROGEN AT 400–700 OC

The International Conference on Chemical and Environmental Engineering
Article 6, Volume 4, 4th International Conference On Chemical & Environmental Engineering, May 2008, Pages 83-100    PDF (836.88 K)
Document Type: Original Article
DOI: 10.21608/iccee.2008.38377
Authors
M. Bahgata1; M. H. Khedr2; W. M.A. El Rouby3
1Researcher, Central Metallurgical Research and Development Institute (CMRDI), Helwan, Egypt.
2Prof. of Materials Science , Chemistry Department, Faculty of Science, Beni-Sueif University, Beni-Sueif, Egypt.
3Faculty of Science, Beni-Sueif University, Beni-Sueif, Egypt.
Abstract
ABSTRACT:
Copper ferrite nanoparticles are coated with magnesium ferrite nanoparticles to form CuFe2O4/ MgFe2O4 core/shell structure by hydrothermal precipitation method. The final precipitate was filtered, washed thoroughly with deionized water and dried at 343K for 24 h. The resulting sample was then calcined at 1173K for 2 h giving the magnetic material CuFe2O4/MgFe2O4 core/shell. The fired powder is then pressed in form of pellets and sintered at 500 oC for 2 h. CuFe2O4/ MgFe2O4 core/shell were isothermally reduced in hydrogen flow at 400-700 oC. The reduced nano-crystalline CuFe2O4/MgFe2O4 core/ shell compacts were characterized by XRD, TEM, SEM, VSM and reflected light microscope. Microstructure of partially and completely reduced samples was studied and the activation energy values were calculated from Arrhenius equation. The activation energy of the initial stage was found to be 9.2kJ/mol, and for the final stage is found to be 23kJ/mol. The approved mathematical formulations for the gas solid reaction were applied and it was found that at the initial stages the reaction is controlled by gaseous diffusion mechanism while the final reaction stages is controlled by the combined gaseous diffusion and interfacial chemical reaction mechanisms.
Keywords
Core–shell; Nanoparticles; Reduction; Kinetics; mechanisms and magnetic properties
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