Synthesis and Characterization of Crystalline FeCo Nanoparticles

2006 ◽  
Vol 6 (11) ◽  
pp. 3417-3421 ◽  
Author(s):  
Chang Woo Kim ◽  
Young Hwan Kim ◽  
Hyun Gil Cha ◽  
Don Keun Lee ◽  
Young Soo Kang
Keyword(s):  
Exchange Coupling ◽  
Chemical Method ◽  
Coupling Effect ◽  
Molar Ratio ◽  
Feco Alloy ◽  
Uniform Size ◽  
Different Temperatures ◽  
Shape Controlled ◽  
Feco Nanoparticles

The monodispersed FeCo nanoparticles were synthesized with borohydride as a reducing agent by coprecipitation method in aqueous solution. The composition and the size of FeCo nanoparticle was controlled by fitting the molar ratio of starting material, the reaction time and the falling rate. To prepare the crystallized nanoparticles, the amorphous FeCo nanoparticles were annealed at the different temperatures for 1 hr, respectively. The size of the crystalline FeCo nanoparticles was controlled in order to maintain the uniform size of 20nm. The as-annealed FeCo alloy could get the highest Ms value of the powder which has been ever synthesized by coprecipitation or other chemical method. The size- and shape-controlled crystalline FeCo nanoparticles can be applied for spring magnet in order to get exchange coupling effect.

Synthesis and Characterization of Antiferromagnetic Kmnf3 Nanoparticles

1999 ◽  
Vol 577 ◽  
Author(s):  
C. Sangregorio ◽  
E. E. Carpenter ◽  
C. J. O'connor
Keyword(s):  
Magnetic Properties ◽  
Reverse Micelles ◽  
Exchange Coupling ◽  
Hysteresis Loops ◽  
Size Control ◽  
Synthesis And Characterization ◽  
Uniform Size ◽  
Average Size ◽  
Aqueous Core

ABSTRACTThe magnetic properties of nanosized antiferromagnetic particles of KMnF3 are presented. The particles were synthesized using the microemulsion technique, i.e. by using the aqueous core of reverse micelles as constrained microreactors for the precipitation of the particles. The structural characterization of the samples, accomplished by TEM and XRD, reveal that the samples consist of cubic-shaped, crystalline KMnF3 nanoparticles of uniform size. Control over the average size of the particles was achieved by changing the reaction time. Four different samples of average size in the range 13-35 nm were prepared. DC magnetic susceptibility measurements revealed superparamagnetic behavior of the particles. Hysteresis loops measured after field cooling the samples through TN were shifted. The shift is ascribed to the exchange coupling between the antiferromagnetic core of the particles and the uncompensated spin shell surrounding it.

scholarly journals Methods of characterization of multiphase Nd-Fe-B melt-spun alloys

2007 ◽  
Vol 39 (2) ◽  
pp. 193-198 ◽  
Author(s):  
A. Grujic ◽  
V. Cosovic ◽  
J. Stajic-Trosic ◽  
A. Maricic ◽  
N. Talijan
Keyword(s):  
Magnetic Material ◽  
Exchange Coupling ◽  
Permanent Magnets ◽  
Coupling Effect ◽  
Melt Spun ◽  
Methods And Techniques ◽  
New Type ◽  
Insight Into ◽  
Microstructure And Magnetic Properties

Nanocomposite permanent magnetic materials based on Nd-Fe-B alloys with a low Nd content are a new type of permanent magnetic material. The microstructure of these nanocomposite permanent magnets is composed of a mixture of magnetically soft and hard phases providing the so called exchange coupling effect. Beside the optimization process parameters, methods of characterization have a very important role in the design of an optimal magnetic matrix of multiphase melt-spun Nd-Fe-B alloys. Different methods and techniques of characterization were used for observation and study of the microstructure evolution during crystallization. A summary results of measurements using different methods of characterization are presented to enable a better insight into relations between the microstructure and magnetic properties of the investigated melt-spun Nd-Fe-B alloys. .

Fabrication and Characterization of Size- and Shape-Controlled C60 Nano/microcrystals by Solvent-Induced Reprecipitation Process (SIRP)

2007 ◽  
Vol 1054 ◽  
Author(s):  
Akito Masuhara ◽  
Zhenquan Tan ◽  
Hitoshi Kasai ◽  
Hachiro Nakanishi ◽  
Hidetoshi Oikawa
Keyword(s):  
Crystal Structure ◽  
Molar Ratio ◽  
Hexagonal Crystal Structure ◽  
Hexagonal Crystal ◽  
Crystal Solvates ◽  
Integrated Devices ◽  
Shape Controlled ◽  
Fabrication And Characterization ◽  
Shape And Size

ABSTRACTWe have first developed useful Solvent-Induced Reprecipitation Process, and have first succeeded in fabricating C60 nano/microcrystals with various shape and size, using m-xylene and 2-propanol as good and poor solvents, respectively.It was found that the resulting C60 nano/microcrystals had a hexagonal crystal structure, and that were a kind of crystal solvates in which the molar ratio of C60 to m-xylene was 3:2. C60 nano/microcrystals could be said to be important nano components of integrated devices in electronics.

Synthesis of FeCo Alloy Nanoparticles for Electromagnetic Absorber by Polyol Method

2020 ◽  
Vol 20 (8) ◽  
pp. 4926-4932
Author(s):  
Dae Seok Seo ◽  
Jong Hwan Park ◽  
Jae Chul Ro ◽  
Kyung Sub Lee ◽  
Su Jung Suh
Keyword(s):  
Electron Microscopy ◽  
Synthesis Temperature ◽  
Alloy Nanoparticles ◽  
Feco Alloy ◽  
X Ray Diffraction ◽  
Molar Ratios ◽  
Transmission Electron ◽  
Different Temperatures ◽  
Optimized Conditions ◽  
Feco Nanoparticles

The correlations among magnetic properties, synthesis temperature, and composition of FeCo nanoparticles were investigated herein. Fe80Co20 alloy nanoparticles synthesized at different temperatures (383, 393, 403, 413, 428, and 443 K) showed variable compositions and aggregation degrees of the FeCo nanoparticles. Under the optimized conditions of synthesis temperature of 403 K and duration of 1 h, FeCo nanoparticles were synthesized at molar ratios of 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, and 1:9. The FeCo alloy nanoparticles were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, vibrating sample magnetometer, fourier transform infrared, and network analyzer. With increasing Co content, the extent of aggregation increased. The cobalt ferrite phase was detected under some conditions, and all FeCo nanoparticles showed high saturation magnetization and low coercive forces. The prepared FeCo nanoparticles exhibited high permeability at a high frequency range.

Synthesis and Characterization of Nanocrystalline ZnO Powders by a Direct Thermal Decomposition Route Using Zinc Nitrate Hexahydrate

2013 ◽  
Vol 770 ◽  
pp. 68-71 ◽  
Author(s):  
Supphadate Sujinnapram ◽  
Uraiphorn Termsuk ◽  
Atcharawan Charoentam ◽  
Sutthipoj Sutthana
Keyword(s):  
Thermal Decomposition ◽  
Crystallization Temperature ◽  
Zinc Nitrate ◽  
Zinc Nitrate Hexahydrate ◽  
Absorption Peak ◽  
Synthesis And Characterization ◽  
Nitrate Hexahydrate ◽  
Different Temperatures ◽  
Zno Powders

The nanocrystalline ZnO powders were synthesized by a direct thermal decomposition using zinc nitrate hexahydrate as starting materials. The precursor was characterized by TG-DTA to determine the thermal decomposition and crystallization temperature which was found to be at 325 oC. The precursors were calcined at different temperatures of 400, 500, and 600°C for 4 h. The structure of the prepared samples was studied by XRD, confirming the formation of wurtzite structure. The synthesized powders exhibited the UV absorption below 400 nm (3.10 eV) with a well defined absorption peak at around 285 nm (4.35 eV). The estimated direct bandgaps were obtained to be 3.19, 3.16, and 3.14 eV for the ZnO samples thermally decomposed at 400, 500, and 600°C, respectively.

Structural Characterization of Two Novel Oxidative Derivatives of Cyclosporine Generated By a Chemical Method

1998 ◽  
Vol 31 (3) ◽  
pp. 173-180 ◽  
Author(s):  
WingT Liu ◽  
Kirk Marat ◽  
Ying Ren ◽  
RonaldT Eng ◽  
PuiY Wong
Keyword(s):  
Structural Characterization ◽  
Chemical Method ◽  
Derivatives Of

scholarly journals Facile Synthesis and Characterization of Palm CNF-ZnO Nanocomposites with Antibacterial and Reinforcing Properties

2021 ◽  
Vol 22 (11) ◽  
pp. 5781
Author(s):  
Janarthanan Supramaniam ◽  
Darren Yi Sern Low ◽  
See Kiat Wong ◽  
Loh Teng Hern Tan ◽  
Bey Fen Leo ◽  
...  
Keyword(s):  
Plant Biomass ◽  
Cellulose Nanofibers ◽  
High Strength ◽  
Salmonella Typhi ◽  
Particle Sizes ◽  
Mechanical Reinforcement ◽  
Uniform Size ◽  
Preparation Methods ◽  
Potential Applications

Cellulose nanofibers (CNF) isolated from plant biomass have attracted considerable interests in polymer engineering. The limitations associated with CNF-based nanocomposites are often linked to the time-consuming preparation methods and lack of desired surface functionalities. Herein, we demonstrate the feasibility of preparing a multifunctional CNF-zinc oxide (CNF-ZnO) nanocomposite with dual antibacterial and reinforcing properties via a facile and efficient ultrasound route. We characterized and examined the antibacterial and mechanical reinforcement performances of our ultrasonically induced nanocomposite. Based on our electron microscopy analyses, the ZnO deposited onto the nanofibrous network had a flake-like morphology with particle sizes ranging between 21 to 34 nm. pH levels between 8–10 led to the formation of ultrafine ZnO particles with a uniform size distribution. The resultant CNF-ZnO composite showed improved thermal stability compared to pure CNF. The composite showed potent inhibitory activities against Gram-positive (methicillin-resistant Staphylococcus aureus (MRSA)) and Gram-negative Salmonella typhi (S. typhi) bacteria. A CNF-ZnO-reinforced natural rubber (NR/CNF-ZnO) composite film, which was produced via latex mixing and casting methods, exhibited up to 42% improvement in tensile strength compared with the neat NR. The findings of this study suggest that ultrasonically-synthesized palm CNF-ZnO nanocomposites could find potential applications in the biomedical field and in the development of high strength rubber composites.

scholarly journals Synthesis and Characterization of Partially Renewable Oleic Acid-Based Ionomers for Proton Exchange Membranes

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 130
Author(s):  
Carlos Corona-García ◽  
Alejandro Onchi ◽  
Arlette A. Santiago ◽  
Araceli Martínez ◽  
Daniella Esperanza Pacheco-Catalán ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Proton Conductivity ◽  
Electrochemical Impedance ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Molar Ratio ◽  
Aromatic Diamines ◽  
Chemical Structures ◽  
Long Chain

The future availability of synthetic polymers is compromised due to the continuous depletion of fossil reserves; thus, the quest for sustainable and eco-friendly specialty polymers is of the utmost importance to ensure our lifestyle. In this regard, this study reports on the use of oleic acid as a renewable source to develop new ionomers intended for proton exchange membranes. Firstly, the cross-metathesis of oleic acid was conducted to yield a renewable and unsaturated long-chain aliphatic dicarboxylic acid, which was further subjected to polycondensation reactions with two aromatic diamines, 4,4′-(hexafluoroisopropylidene)bis(p-phenyleneoxy)dianiline and 4,4′-diamino-2,2′-stilbenedisulfonic acid, as comonomers for the synthesis of a series of partially renewable aromatic-aliphatic polyamides with an increasing degree of sulfonation (DS). The polymer chemical structures were confirmed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (1H, 13C, and 19F NMR) spectroscopy, which revealed that the DS was effectively tailored by adjusting the feed molar ratio of the diamines. Next, we performed a study involving the ion exchange capacity, the water uptake, and the proton conductivity in membranes prepared from these partially renewable long-chain polyamides, along with a thorough characterization of the thermomechanical and physical properties. The highest value of the proton conductivity determined by electrochemical impedance spectroscopy (EIS) was found to be 1.55 mS cm−1 at 30 °C after activation of the polymer membrane.

scholarly journals Biodiesel Production from Melia azedarach and Ricinus communis Oil by Transesterification Process

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 427 ◽  
Author(s):  
Muhammad Awais ◽  
Sa’ed A Musmar ◽  
Faryal Kabir ◽  
Iram Batool ◽  
Muhammad Asif Rasheed ◽  
...  
Keyword(s):  
Ricinus Communis ◽  
Cost Effective ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Melia Azedarach ◽  
Renewable Fuel ◽  
Animal Fats ◽  
Edible Crops ◽  
American Society

Biodiesel is a renewable fuel usually produced from vegetable oils and animal fats. This study investigates the extraction of oil and its conversion into biodiesel by base-catalyzed transesterification. Firstly, the effect of various solvents (methanol, n-hexane, chloroform, di-ethyl ether) on extraction of oil from non-edible crops, such as R. communis and M. azedarach, were examined. It was observed that a higher concentration of oil was obtained from R. communis (43.6%) as compared to M. azedarach (35.6%) by using methanol and n-hexane, respectively. The extracted oils were subjected to NaOH (1%) catalyzed transesterification by analyzing the effect of oil/methanol molar ratio (1:4, 1:6, 1:8 and 1:10) and varying temperature (20, 40, 60 and 80 °C) for 2.5 h of reaction time. M. azedarach yielded 88% and R. communis yielded 93% biodiesel in 1:6 and 1:8 molar concentrations at ambient temperature whereas, 60 °C was selected as an optimum temperature, giving 90% (M. azedarach) and 94% (R. communis) biodiesel. The extracted oil and biodiesel were characterized for various parameters and most of the properties fulfilled the American Society for Testing and Materials (ASTM) standard biodiesel. The further characterization of fatty acids was done by Gas Chromatography/Mass Spectrometer (GC/MS) and oleic acid was found to be dominant in M. azedarach (61.5%) and R. communis contained ricinoleic acid (75.53%). Furthermore, the functional groups were analyzed by Fourier Transform Infrared Spectroscopy. The results suggested that both of the oils are easily available and can be used for commercial biodiesel production at a cost-effective scale.

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