Sol–gel-based chemical synthesis of NdFeB hard magnetic nanoparticles

2018 ◽  
Vol 32 (34n36) ◽  
pp. 1840070 ◽  
Author(s):  
Jinshan Zhang ◽  
Wei Wu ◽  
Fangshi Meng ◽  
Hao Ding ◽  
Jiling Dong
Keyword(s):  
Saturation Magnetization ◽  
Sol Gel ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Oxide Powders ◽  
Intermediate Phases ◽  
Washing Process ◽  
Oxide Phases

NdFeB nanoparticles were synthesized by a sol–gel method. Firstly, NdFeB gel was prepared by using citric acid and glycol as the gel, and the corresponding salts of Nd, Fe and boric acid. The gel was subsequently annealed under a high temperature condition to obtain NdFeB-oxide phases. Then NdFeB nanoparticles were yielded by reductive annealing of precursors. Microstructure, phase composition and magnetic properties were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM) and vibrating sample magnetometer (VSM), and also differential scanning calorimetry (DSC) analysis was performed to determine the annealing temperature. At 400[Formula: see text]C, intermediate phases of Fe3BO5 and NdBO3 were formed and stable up to 600[Formula: see text]C; while at 800[Formula: see text]C, they would reacted in presence of oxygen to form NdFeO3 and B2O3. Nd2O3 and Fe2O3 were also formed at this temperature. SEM micrographs of reduced powders after washing process showed an average particle size below 100 nm in all the samples. VSM results showed the oxide powder formed at 800[Formula: see text]C had a coercivity of 1.55 kOe and a saturation magnetization of 1.08 emu/g. The powder synthesized by reduction of oxide powders at 800[Formula: see text]C had a coercivity of 1.02 kOe and a saturation magnetization of 14.17 emu/g.

A Calcination Technology for Ultrafine La3NbO7 Powder Prepared by Sol-Gel Process

2011 ◽  
Vol 412 ◽  
pp. 271-274
Author(s):  
Ying Li ◽  
Qiang Xu ◽  
Ling Dai
Keyword(s):  
Single Phase ◽  
Sol Gel ◽  
Average Particle Size ◽  
Complex Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Acid Complex ◽  
Calcination Process ◽  
Sol Gel Process

In order to prepare ultrafine La3NbO7 powder, a potential material for thermal barrier coatings, the calcination process of La3NbO7 was studied in this paper.The precursor of La3NbO7 was synthesized by using a citric acid complex method. A calcination process had been systematically investigated. The reaction temperature was determined by differential scanning calorimetry (DSC). The phase composition of powders was characterized by X-ray diffraction (XRD), and the morphology was obtained by scanning electron microscope (SEM). The results revealed that the single-phase La3NbO7 powder could be successfully prepared while the calcination temperature exceeded 800°C and a better morphology could be maintained at 800°C for 4 hours. Considering all above, an optimum calcination scheme was adopted at 800°C for 4 hours. The as-prepared La3NbO7 powders had a grain size of about 50nm and an average particle size of about 300nm.

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

Pb2+ and Ce3+ Doped SrZnO2: New Blue Luminescent Phosphors

2006 ◽  
Vol 916 ◽  
Author(s):  
Alp Manavbasi ◽  
Jeffrey C LaCombe
Keyword(s):  
Sol Gel ◽  
Average Particle Size ◽  
Broad Band ◽  
Emission Spectra ◽  
Broad Emission Band ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Broad Emission ◽  
Diffraction Patterns ◽  
Individual Particles

AbstractTwo new blue emitting phosphors, SrZnO2:Pb2+ and Ce3+ were synthesized by adipic acid and sucrose templated sol-gel routes, respectively. The resulting phosphor particles were fine, nanocrystalline and pure. The optimum activator concentrations were found to be 1 mol% Pb2+ and 12 mol% Ce3+. Two excitation bands centered at 283 and 317 nm, plus a weak shoulder at 275 nm were observed for Pb2+ doped samples, however only one broad excitation band with a maximum at 294 nm was observed for Ce3+ doped samples fired at 1000 °C for 2h. The emission spectra of SrZnO2:Pb2+ showed a very broad band extending from 374 to 615 nm with a maximum at ~455 nm which was ascribed to the 3P1 ¡æ 1S0 transition on the Pb2+ ions allowed by the strong spin-orbit (SO) coupling. Similarly, SrZnO2:Ce3+ showed a broad emission band extending from 374 to 609 nm and centered at 467 nm. This broad emission was attributed to the 5d1 ¡æ 4f1 transition of Ce3+ ions. The lower level 2F5/2 of the 4f1 is populated but the level 2F7/2 is almost empty at room temperature where all measurements were taken. The luminescence properties of Ce3+, K+ co-doped SrZnO2 revealed that the characteristic band locations remained the same and the ratio of emission to excitation intensities were constant. X-ray diffraction patterns showed that the SrZnO2 phase started to form at 900 °C (after 2 hrs), and the single-phase SrZnO2 obtained at 1000 °C. SEM micrographs of both phosphors have a rounded and filled morphology for individual particles with an approximate diameter of 50-250 nm. Dynamic light scattering studies revealed that average particle size is around 1 ¥ìm for both phosphors.

Porous Ceramic Humidity Sensors Using Sol-Gel Processed ZrTiO4 Nanoparticles

2006 ◽  
Vol 45 ◽  
pp. 1803-1808 ◽  
Author(s):  
I.C. Cosentino ◽  
E.N.S. Muccillo ◽  
F.M. Vichi ◽  
R. Muccillo
Keyword(s):  
Porous Ceramic ◽  
Mercury Porosimetry ◽  
Sol Gel ◽  
Average Particle Size ◽  
Nitrogen Adsorption ◽  
Zirconium Oxychloride ◽  
Average Particle ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Adsorption Analysis

Ceramic ZrTiO4 powders were prepared by a sol-gel method using zirconium oxychloride and titanium tetraisopropoxide. In situ high temperature X-ray diffraction results show that crystallization of the amorphous gel starts at 400°C. Single-phase ZrTiO4 nanoparticles of 46 nm average particle size, determined by nitrogen adsorption analysis, were obtained after heat treatment at 450°C for 1 h. After pressing these sinteractive powders, pellets with controlled pore size distribution were obtained by sintering at temperatures as low as 400°C. The analysis of pores by mercury porosimetry gives an average porosity of 45%. The electrical resistivity, determined by impedance spectroscopy measurements at 24°C under different humidity environments, shows the ability of these pellets to adsorb water vapor in the porous surfaces.

scholarly journals PCL/PHBV Microparticles as Innovative Carriers for Oral Controlled Release of Manidipine Dihydrochloride

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Fernanda Malaquias Barboza ◽  
Willian Moreira Machado ◽  
Luiz Renato Olchanheski Junior ◽  
Josiane Padilha de Paula ◽  
Sônia Faria Zawadzki ◽  
...  
Keyword(s):  
Controlled Release ◽  
Animal Studies ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Chemically Modified ◽  
Diffraction Patterns

Microparticles of poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) containing manidipine dihydrochloride (MAN) were successfully prepared by the simple emulsion/solvent evaporation method. All formulations showed loading efficiency rates greater than 80% and average particle size less than 8 μm. Formulations had spherical shape with smooth and porous surface for PCL and PHBV, respectively. According to Fourier-transform infrared spectroscopy, initial components were not chemically modified during microencapsulation. X-ray diffraction patterns and differential scanning calorimetry demonstrated that this process led to drug amorphization.In vitrodissolution studies showed that all microparticles prolonged MAN release, mainly which one obtained using PCL that contained 5% of drug loaded (PCL-M5). Animal studies demonstrated that formulationPCL-M5was able to keep the variation of mean arterial pressure after phenylephrine administration up to 24 hours. These data confirmed the sustained antihypertensive effect of the investigated microparticles. Results provided an experimental basis for using formulationPCL-M5as a feasible carrier for oral controlled release of MAN intended for treating high blood pressure.

scholarly journals Preparation, characterization and analysis of zinc oxide nano-particles using a sol-gel technique as an inhibitor for bacteria

2020 ◽  
Vol 11 (1) ◽  
pp. 747-754
Author(s):  
Saja S. Al-Taweel ◽  
Rana S. Al-Taweel ◽  
Hasan M. Luaibi
Keyword(s):  
Zinc Oxide ◽  
Sol Gel ◽  
Average Particle Size ◽  
Spherical Shape ◽  
Nano Particles ◽  
Klebsiella Pneumonia ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Zno Nps ◽  
Atomic Force

In this work, zinc oxide nanoparticles (ZnO - NPs) were prepared using a sol-gel methodology and tested for their antibacterial activity against each of the following pathogenic species: Escherichia coli, Klebsiella pneumonia, and Staphylococcus aureus by well diffusion assay. The sample prepared was characterized by different techniques: Atomic Force Microscope AFM; Fourier Transform Infrared FT-IR; Scanning Electron Microscope SEM and X-Ray Diffraction Spectroscopy XRD. The XRD result showed that ZnO - NPs presence in wurtzite the structure of ZnO. The AFM and SEM of the surface analysis indicate that the most ZnO – NPs appear approximately in a spherical shape with some agglomeration. The average particle size for  ZnO - NPs is nearly 37 nm. Volumes 25µl, 50µl, 75µl, 100µl, 125µl, and 150µl of 10 mg\ ml concentration of  ZnO - NPs were used, the antimicrobial activity results showed that ability for  ZnO - NPs to inhibit the growth of S.aureus increased as the solution volume increased, while the growing of (K. pneumonia) and (E. coli) was inhibited only with the volume 75µl where the inhibition zones diameters were 15mm and 10mm respectively.

scholarly journals Effects of Hydrothermal and Microwave Dual Treatment and Zein on the Enzymolysis of High Amylose Corn Starch

Gels ◽  
2022 ◽  
Vol 8 (1) ◽  
pp. 29
Author(s):  
Jie Liu ◽  
Qiuye Yang ◽  
Tiantian Yuan ◽  
Yawei Liu ◽  
Guihong Fang
Keyword(s):  
Moisture Content ◽  
Corn Starch ◽  
Average Particle Size ◽  
Microwave Treatment ◽  
Decomposition Temperature ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Amylose

Resistant starch (RS) type 2-high-amylose corn starch (HACS) was subjected to simultaneous hydrothermal (25% moisture content, 90 °C for 12 h) and microwave (35% moisture content, 40 W/g microwaving for 4 min) treatment and zein (at a zein to treated starch ratio of 1:5, 50 °C for 1 h) to improve its resistance to enzymolysis. Scanning electron microscopy (SEM) highlighted the aggregation and adhesion of the composite. The average particle size of the composite (27.65 μm) was exceeded that of both the HACS (12.52 μm) and the hydrothermal and microwave treated HACS (hydro-micro-HACS) (12.68 μm). The X-ray diffraction results revealed that the hydro-micro-HACS and composite remained B-type, while their crystallinity significantly decreased to 16.98% and 12.11%, respectively. The viscosity of the hydro-micro-HACS and composite at 50 °C was 25.41% and 35.36% lower than that of HACS. The differential scanning calorimetry (DSC) results demonstrated that the composite displayed a new endothermic peak at 95.79 °C, while the weight loss rate and decomposition temperature were 7.61% and 2.39% lower than HACS, respectively. The RS content in HACS, the hydro-micro-HACS, and composite was 47.12%, 57.28%, and 62.74%, respectively. In conclusion, hydrothermal and microwave treatment combined with zein provide an efficient physical strategy to enhance the RS type 2-HACS.

scholarly journals PREPARATION AND STUDY OF FERRITE GARNET R3Fe5O12 (R=Y, Gd, Dy) NANOPARTICLES

2012 ◽  
Vol 15 (2) ◽  
pp. 27-34
Author(s):  
Nguyet Thi Thuy Dao ◽  
Duong Phuc Nguyen ◽  
Hien Duc Than
Keyword(s):  
Particle Size ◽  
Sol Gel ◽  
Average Particle Size ◽  
Particle Morphology ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Ferrite Garnet ◽  
Transmission Electron ◽  
Scherrer Formula

This paper presents the synthesis and characterization of Y3Fe5O12, Gd3Fe5O12 and Dy3Fe5O12 nanoparticles by sol-gel method using initial salts solution of Y(NO3)3, Gd(NO3)3, Dy(NO3)3, Fe(NO3). The lattice constant, crystallite size and particle morphology of these ferrite garnet nanoparticles were studied by using X-ray diffraction and transmission electron microscopy (TEM). The results showed that the garnet samples prepared by this method were formed at 800oC, which is lower than the sintering temperature for ceramic bulk samples (1400oC). The particle size is in the range 25- 40 nm as observed via TEM image and the average particle size was found to be 37nm using Debye- Scherrer formula.

scholarly journals Fabrication and characterisation of Fe2O3/chitosan aerogel-like spheres

2021 ◽  
Vol 10 (1) ◽  
pp. 74-78
Author(s):  
Nhan Dang Thi Thanh ◽  
Don Truong Thi ◽  
Thang Le Quoc ◽  
Tien Tran Dong ◽  
Son Le Lam
Keyword(s):  
High Surface ◽  
Sol Gel ◽  
Average Particle Size ◽  
High Surface Area ◽  
Hollow Structure ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Factors Affecting ◽  
Sol Gel Process ◽  
High Surface Area Materials

Presently, biopolymer materials have been given more attention for their outstanding properties, high efficiencies and promising applications in various fields. In this study, Fe2O3/chitosan aerogel-like spheres were successfully prepared from chitosan and FeCl3 by sol–gel process and freeze-drying to provide high-surface area materials. The factors affecting the material synthesis have been studied. The asprepared Fe2O3/chitosan material was characterized by Infrared Spectroscopy (IR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) methods. The results showed that the aerogel spheres have a hollow structure made of chitosan nanofibril networks. Fe2O3 nanoparticles get high crystallinity and have an average particle size of 33 nm.

Preparation and Research of α-Fe/Montmorillonite Magnetic Material

2014 ◽  
Vol 809-810 ◽  
pp. 433-437
Author(s):  
Cheng Cheng Shi ◽  
Long Gui Peng ◽  
Zhi Wang
Keyword(s):  
Magnetic Material ◽  
Particle Size ◽  
Composite Material ◽  
Saturation Magnetization ◽  
Average Particle Size ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Layer Spacing ◽  
Particle Size Analyzer

α-Fe/montmorillonite (MMT) magnetic material was successfully prepared by the in-situ pillared-reduction method. The composite material was characterized by X-ray diffraction (XRD), laser particle size analyzer and other instruments. The magnetic property was researched by saturation magnetization. The results showed that: when 0.1mol/L hydroxyl-Fe was added as pillared agent, hydroxyl-Fe and cation of the MMT exchanged, leading to the inter-layer spacing expanded to 1.41nm and reached saturated pillared point. MMT interlayer hydroxyl-Fe was completely restored to α-Fe grains of 116nm when reducing agent was 0.2mol/L and produced α-Fe/MMT composite material. The average particle size of the composite was 5.529μm, the specific saturation magnetization was 0.812emu/g (9×103A/moutside magnetic field) and exhibited ferromagnetism.

Sign in / Sign up

Export Citation Format

Share Document