scholarly journals Comparative studies on impact of synthesis methods on structural and magnetic properties of magnesium ferrite nanoparticles

2014 ◽  
Vol 8 (3) ◽  
pp. 137-143 ◽  
Author(s):  
Navneet Kaur ◽  
Manpreet Kaur

Magnesium ferrite nanoparticles (NPs) were synthesized by co-precipitation, sol-gel and solution combustion methods. Polyethylene glycol (PEG), urea and oxalyl dihydrazide (ODH) were used as fuels for the combustion. Various physicochemical techniques viz. X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Fourier transform infrared spectroscopy (FT-IR), BET surface analysis and transmission electron microscopy (TEM) were utilized to study the effect of synthetic methodology on the properties of synthesized NPs. Differences in crystallinity, surface area, particle size and magnetic parameters of the ferrite NPs synthesized by different methods were observed. XRD pattern of NPs obtained by sol-gel and combustion methods confirmed phase purity where as in co-precipitation method ?-Fe2O3 was detected as impurity phase which also resulted in greater value of physical density and lowering of magnetic parameters of the final thermolysis product. TEM micrographs indicated that ferrite NPs are spherical with average diameter of 12-25 nm. Presence of rectangular shaped crystallites of ?-Fe2O3 was clearly evident in the TEM images of the NPs synthesized by co-precipitation method.

2015 ◽  
Vol 1088 ◽  
pp. 371-376 ◽  
Author(s):  
Xia Zhang ◽  
Cui Xia Yan ◽  
Rong Feng Guan

Spherical YAG:Ce3+phosphors were synthesized by three different routes namely sol-gel method, co-precipitation method and solvethermal method. The microstructure, crystallization and luminescent properties of the phosphors were studied in order to find the best processing parameter for spherical shape and good luminescence properties of YAG:Ce3+phosphor. Adding citric acid to the precursor solution resulted in the formation of spherical particles in sol-gel method. YAG:Ce3+phosphor made by co-precipitation method was separated with PEG2000, and its spherical particles of size was around 500nm. The hydro-thermal method could get perfect spherical appearance, but it needed heat treatment improve the luminescence property.


2015 ◽  
Vol 10 (1) ◽  
pp. 2566-2582
Author(s):  
Anwar Ul Haq ◽  
Farwa Mushtaq ◽  
M. Anis-ur-Rehman

Ba1-xPbxFe12O19 composition (x=0.0 to 1.0) synthesized by Co-precipitation and Sol-Gel  methods. In Co-precipitation method BaCO3, PbO and Fe (NO3)3 .9H2O were used as basic ingredients. Acids and Di-H2O  were used as solvents. Molar ratio of cations was 12.   pH of solution kept constant at 13.  All samples sintered at 965±5oC for three hours.  Lead own properties, synthesis at room temperature and substitution in R-block of structure were the reasons for decrease of phase purity from “x” =0.0 to 70% for “x”=1.0. Decrease in phase purity   and heterogeneity of material caused the properties to decrease. In Sol gel method, Nitrates (salts) and Ethylene glycol (liquid) were the basic material used. The mixed solutions dried out on a hot plate whose temperature was maintained constant at 200±2oC. Pellets formed by applying suitable hydraulic pressure and then sintered at same temperature written above i.e. 965±5oC for three hours. 100% phase purity achieved. All properties modified. Temperature and frequency dependent electrical properties investigated and reported here. DC and AC obtained properties were useful for different electronics and computer devices like capacitors, smart storage devices and multilayer chip inductors. Overall, both these properties improved through sol-gel method as compared to co-precipitation method. It was because of improvement in phase purity and change in morphology of synthesized material. 


Author(s):  
Anastasiia Bolotnikova

The superconducting cuprate Y3Ba5Cu8Ox was obtained with the help of sol-gel technology (sample C), co-precipitation of hydroxocarbonates (sample B) and solid-phase synthesis methods (A). Based on the results of scanning electron microscopy and methods based on the analysis of X-ray diffraction data: the Williamson-Hall construction and the Scherrer formula, features of the microstructure of the synthesized samples are established. The smallest particle size has a sample that has been synthesized by the sol-gel method. The tendency to aggregation and sedimentation for this sample is the smallest. The sample obtained by the co-precipitation method has larger grains and a higher tendency to aggregate. The size of the microparticles and the tendency to aggregate for the sample synthesized by the solid-phase method are greatest. The morphology of particles was studied using three methods: SEM, Scherrer and Williamson-Hall formulas and the following results were found: particle size depends on the synthesis method, but a relatively narrow size distribution within one synthesis method remains, the value of crystal lattice microdeformation for samples increases in a line: C sample– A sample– B sample. Thus, the work was carried out for determining the size, structure and morphology of superconducting phases. It expands knowledge in the field of research of superconducting compounds


2021 ◽  
Vol 11 (22) ◽  
pp. 11075
Author(s):  
Angela Spoială ◽  
Cornelia-Ioana Ilie ◽  
Luminița Narcisa Crăciun ◽  
Denisa Ficai ◽  
Anton Ficai ◽  
...  

The interconnection of nanotechnology and medicine could lead to improved materials, offering a better quality of life and new opportunities for biomedical applications, moving from research to clinical applications. Magnetite nanoparticles are interesting magnetic nanomaterials because of the property-depending methods chosen for their synthesis. Magnetite nanoparticles can be coated with various materials, resulting in “core/shell” magnetic structures with tunable properties. To synthesize promising materials with promising implications for biomedical applications, the researchers functionalized magnetite nanoparticles with silica and, thanks to the presence of silanol groups, the functionality, biocompatibility, and hydrophilicity were improved. This review highlights the most important synthesis methods for silica-coated with magnetite nanoparticles. From the presented methods, the most used was the Stöber method; there are also other syntheses presented in the review, such as co-precipitation, sol-gel, thermal decomposition, and the hydrothermal method. The second part of the review presents the main applications of magnetite-silica core/shell nanostructures. Magnetite-silica core/shell nanostructures have promising biomedical applications in magnetic resonance imaging (MRI) as a contrast agent, hyperthermia, drug delivery systems, and selective cancer therapy but also in developing magnetic micro devices.


2016 ◽  
Vol 875 ◽  
pp. 24-44
Author(s):  
Ming Guo Ma ◽  
Shan Liu ◽  
Lian Hua Fu

CaCO3 has six polymorphs such as vaterite, aragonite, calcite, amorphous, crystalline monohydrate, and hexahydrate CaCO3. CaCO3 is a typical biomineral that is abundant in both organisms and nature and has important industrial applications. Cellulose could be used as feedstocks for producing biofuels, bio-based chemicals, and high value-added bio-based materials. In the past, more attentions have been paid to the synthesis and applications of CaCO3 and cellulose/CaCO3 nanocomposites due to its relating properties such as mechanical strength, biocompatibility, and biodegradation, and bioactivity, and potential applications including biomedical, antibacterial, and water pretreatment fields as functional materials. A variety of synthesis methods such as the hydrothermal/solvothermal method, biomimetic mineralization method, microwave-assisted method, (co-) precipitation method, and sonochemistry method, were employed to the preparation of CaCO3 and cellulose/CaCO3 nanocomposites. In this chapter, the recent development of CaCO3 and cellulose/CaCO3 nanocomposites has been reviewed. The synthesis, characterization, and biomedical applications of CaCO3 and cellulose/CaCO3 nanocomposites are summarized. The future developments of CaCO3 and cellulose/CaCO3 nanocomposites are also suggested.


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