Sol-gel based chemical synthesis of Nd2Fe14B hard magnetic nanoparticles

Pratap K. Deheri; Viswanathan Swaminathan; Shekhar D. Bhame; Zhongwu Liu; Raju V. Ramanujan

doi:10.1021/cm103148n

Sol-gel based chemical synthesis of Nd₂Fe₁₄B hard magnetic nanoparticles

Pratap K. Deheri, Viswanathan Swaminathan, Shekhar D. Bhame, Zhongwu Liu, Raju V. Ramanujan

Research output: Contribution to journal › Article › peer-review

114 Citations (Scopus)

Abstract

Nd₂Fe₁₄B hard magnetic nanoparticles were synthesized by chemical synthesis techniques. Nd-Fe-B gel was prepared using NdCl ₃•6H₂O, FeCl₃•6H₂O, H ₃BO₃, citric acid, and ethylene glycol (EG) by a Pechini type sol-gel method. This gel was subsequently annealed to produce mixed oxide powders. Nd₂Fe₁₄B nanoparticles were prepared from these oxides by a reduction-diffusion process. The phase analysis, structure, and magnetic properties were determined by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) techniques. The mechanism of Nd₂Fe₁₄B formation was investigated by differential scanning calorimetry (DSC), XRD, and thermodynamic free energy change data. Our experimental and modeling results showed that the reduction-diffusion of the Nd-Fe-B mixed oxide was a three step process. The reduction of Fe ₂O₃ to Fe and B₂O₃ to B occurred at 300 °C. NdH₂ and Fe was formed from Nd₂O₃ and NdFeO₃ at 620 °C. The Nd₂Fe₁₄B phase was formed from NdH₂, Fe, and B at 692 °C. The coercivity of as-synthesized powder was 6.1 kOe. The Henkel plot showed that this powder was exchange coupled; removal of CaO by washing led to dipolar interactions and a decrease in coercivity.

Original language	English
Pages (from-to)	6509-6517
Number of pages	9
Journal	Chemistry of Materials
Volume	22
Issue number	24
DOIs	https://doi.org/10.1021/cm103148n
Publication status	Published - Dec 28 2010
Externally published	Yes

ASJC Scopus Subject Areas

General Chemistry
General Chemical Engineering
Materials Chemistry

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10.1021/cm103148n

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@article{827fd6b007f0466a8d015c7cd4c7c675,

title = "Sol-gel based chemical synthesis of Nd2Fe14B hard magnetic nanoparticles",

abstract = "Nd2Fe14B hard magnetic nanoparticles were synthesized by chemical synthesis techniques. Nd-Fe-B gel was prepared using NdCl 3•6H2O, FeCl3•6H2O, H 3BO3, citric acid, and ethylene glycol (EG) by a Pechini type sol-gel method. This gel was subsequently annealed to produce mixed oxide powders. Nd2Fe14B nanoparticles were prepared from these oxides by a reduction-diffusion process. The phase analysis, structure, and magnetic properties were determined by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) techniques. The mechanism of Nd2Fe14B formation was investigated by differential scanning calorimetry (DSC), XRD, and thermodynamic free energy change data. Our experimental and modeling results showed that the reduction-diffusion of the Nd-Fe-B mixed oxide was a three step process. The reduction of Fe 2O3 to Fe and B2O3 to B occurred at 300 °C. NdH2 and Fe was formed from Nd2O3 and NdFeO3 at 620 °C. The Nd2Fe14B phase was formed from NdH2, Fe, and B at 692 °C. The coercivity of as-synthesized powder was 6.1 kOe. The Henkel plot showed that this powder was exchange coupled; removal of CaO by washing led to dipolar interactions and a decrease in coercivity.",

author = "Deheri, {Pratap K.} and Viswanathan Swaminathan and Bhame, {Shekhar D.} and Zhongwu Liu and Ramanujan, {Raju V.}",

year = "2010",

month = dec,

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doi = "10.1021/cm103148n",

language = "English",

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T1 - Sol-gel based chemical synthesis of Nd2Fe14B hard magnetic nanoparticles

AU - Deheri, Pratap K.

AU - Swaminathan, Viswanathan

AU - Bhame, Shekhar D.

AU - Liu, Zhongwu

AU - Ramanujan, Raju V.

PY - 2010/12/28

Y1 - 2010/12/28

N2 - Nd2Fe14B hard magnetic nanoparticles were synthesized by chemical synthesis techniques. Nd-Fe-B gel was prepared using NdCl 3•6H2O, FeCl3•6H2O, H 3BO3, citric acid, and ethylene glycol (EG) by a Pechini type sol-gel method. This gel was subsequently annealed to produce mixed oxide powders. Nd2Fe14B nanoparticles were prepared from these oxides by a reduction-diffusion process. The phase analysis, structure, and magnetic properties were determined by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) techniques. The mechanism of Nd2Fe14B formation was investigated by differential scanning calorimetry (DSC), XRD, and thermodynamic free energy change data. Our experimental and modeling results showed that the reduction-diffusion of the Nd-Fe-B mixed oxide was a three step process. The reduction of Fe 2O3 to Fe and B2O3 to B occurred at 300 °C. NdH2 and Fe was formed from Nd2O3 and NdFeO3 at 620 °C. The Nd2Fe14B phase was formed from NdH2, Fe, and B at 692 °C. The coercivity of as-synthesized powder was 6.1 kOe. The Henkel plot showed that this powder was exchange coupled; removal of CaO by washing led to dipolar interactions and a decrease in coercivity.

AB - Nd2Fe14B hard magnetic nanoparticles were synthesized by chemical synthesis techniques. Nd-Fe-B gel was prepared using NdCl 3•6H2O, FeCl3•6H2O, H 3BO3, citric acid, and ethylene glycol (EG) by a Pechini type sol-gel method. This gel was subsequently annealed to produce mixed oxide powders. Nd2Fe14B nanoparticles were prepared from these oxides by a reduction-diffusion process. The phase analysis, structure, and magnetic properties were determined by Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR), X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), and vibrating sample magnetometer (VSM) techniques. The mechanism of Nd2Fe14B formation was investigated by differential scanning calorimetry (DSC), XRD, and thermodynamic free energy change data. Our experimental and modeling results showed that the reduction-diffusion of the Nd-Fe-B mixed oxide was a three step process. The reduction of Fe 2O3 to Fe and B2O3 to B occurred at 300 °C. NdH2 and Fe was formed from Nd2O3 and NdFeO3 at 620 °C. The Nd2Fe14B phase was formed from NdH2, Fe, and B at 692 °C. The coercivity of as-synthesized powder was 6.1 kOe. The Henkel plot showed that this powder was exchange coupled; removal of CaO by washing led to dipolar interactions and a decrease in coercivity.

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Sol-gel based chemical synthesis of Nd₂Fe₁₄B hard magnetic nanoparticles

Abstract

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