Large scale combustion synthesis of glass-γ-Fe2O3 double shell composite hollow microspheres with tunable magnetic property

RSC Advances ◽  
2016 ◽  
Vol 6 (52) ◽  
pp. 47089-47095 ◽  
Author(s):  
Bin Liao ◽  
Zhenguo An ◽  
Jingjie Zhang

Novel fast dehydration–combustion route to glass-γ-Fe2O3 double shell composite hollow microspheres with low density and tunable magnetic properties.

Author(s):  
Zhenguo An ◽  
Jingjie Zhang

Low density silicate–CoNi–carbon triple shell hollow microspheres with high mechanical strength and controllable electromagnetic properties were prepared on a large scale.


2020 ◽  
Vol 65 (10) ◽  
pp. 904
Author(s):  
V. O. Zamorskyi ◽  
Ya. M. Lytvynenko ◽  
A. M. Pogorily ◽  
A. I. Tovstolytkin ◽  
S. O. Solopan ◽  
...  

Magnetic properties of the sets of Fe3O4(core)/CoFe2O4(shell) composite nanoparticles with a core diameter of about 6.3 nm and various shell thicknesses (0, 1.0, and 2.5 nm), as well as the mixtures of Fe3O4 and CoFe2O4 nanoparticles taken in the ratios corresponding to the core/shell material contents in the former case, have been studied. The results of magnetic research showed that the coating of magnetic nanoparticles with a shell gives rise to the appearance of two simultaneous effects: the modification of the core/shell interface parameters and the parameter change in both the nanoparticle’s core and shell themselves. As a result, the core/shell particles acquire new characteristics that are inherent neither to Fe3O4 nor to CoFe2O4. The obtained results open the way to the optimization and adaptation of the parameters of the core/shell spinel-ferrite-based nanoparticles for their application in various technological and biomedical domains.


2017 ◽  
Vol 13 (1) ◽  
pp. 4486-4494 ◽  
Author(s):  
G.El Damrawi ◽  
F. Gharghar

Cerium oxide in borate glasses of composition xCeO2·(50 − x)PbO·50B2O3 plays an important role in changing both microstructure and magnetic behaviors of the system. The structural role of CeO2 as an effective agent for cluster and crystal formation in borate network is clearly evidenced by XRD technique. Both structure and size of well-formed cerium separated clusters have an effective influence on the structural properties. The cluster aggregations are documented to be found in different range ordered structures, intermediate and long range orders are the most structures in which cerium phases are involved. The nano-sized crystallized cerium species in lead borate phase are evidenced to have magnetic behavior.  The criteria of building new specific borate phase enriched with cerium as ferrimagnetism has been found to keep the magnetization in large scale even at extremely high temperature. Treating the glass thermally or exposing it to an effective dose of ionized radiation is evidenced to have an essential change in magnetic properties. Thermal heat treatment for some of investigated materials is observed to play dual roles in the glass matrix. It can not only enhance alignment processes of the magnetic moment but also increases the capacity of the crystallite species in the magnetic phases. On the other hand, reverse processes are remarked under the effect of irradiation. The magnetization was found to be lowered, since several types of the trap centers which are regarded as defective states can be produced by effect of ionized radiation. 


Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1094
Author(s):  
Bastian Klose ◽  
Daniel Kremer ◽  
Merve Aksit ◽  
Kasper P. van der Zwan ◽  
Klaus Kreger ◽  
...  

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 µm, remains challenging. Here, we report on a series of 4,4′-diphenylmethane substituted bisamides, which we refer to as kinked bisamides, acting as efficient supramolecular foam cell nucleating agents for polystyrene. Self-assembly experiments from solution showed that these bisamides form supramolecular fibrillary or ribbon-like nanoobjects. These kinked bisamides can be dissolved at elevated temperatures in a large concentration range, forming dispersed nano-objects upon cooling. Batch foaming experiments using 1.0 wt.% of a selected kinked bisamide revealed that the mean cell size can be as low as 3.5 µm. To demonstrate the applicability of kinked bisamides in a high-throughput continuous foam process, we performed foam extrusion. Using 0.5 wt.% of a kinked bisamide yielded polymer foams with a foam density of 71 kg/m3 and a homogeneous microcellular morphology with cell sizes of ≈10 µm, which is two orders of magnitude lower compared to the neat polystyrene reference foam with a comparable foam density.


2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Xiaopeng Xiong ◽  
Yong Wang ◽  
Weiwei Zou ◽  
Jiangjiang Duan ◽  
Yun Chen

By dispersing aqueous precipitant in liquid paraffin to prepare a W/O emulsion then adding chitosan (CS) solution, CS microcapsules have been successfully prepared. It is a facile way to prepare polymer microcapsules by using aqueous precipitant or nonsolvent as template, which avoids the removal of template and would free from the necessity to cross-link the microcapsule as usual methods to directly form dense shell. The hollow feature of the obtained materials is revealed. The diameter of the microcapsules ranges from severalμm to over 100 μm. Magnetic CS microcapsules have been prepared in this way when Fe3+and Fe2+were mixed with CS to prepare a mixture starting solution. The appearance and microstructure of the composite microcapsules were studied. The results indicate that the formed Fe3O4nanoparticles are embedded in the CS matrix evenly due to strong interaction between the Fe3O4nanoparticles and the CS molecules. The Fe3O4content and the magnetic properties of the composite microcapsule were measured. The composite microcapsules were calcined in air at 700°C to prepare pure inorganic hollow microspheres. It is general to prepare hollow polymeric or composite particles by using this method.


2011 ◽  
Vol 25 (26) ◽  
pp. 3435-3442
Author(s):  
XIAOYAN YAO

Wang–Landau algorithm of Monte Carlo simulation is performed to understand the thermodynamic and magnetic properties of antiferromagnetic Ising model on honeycomb lattice. The internal energy, specific heat, free energy and entropy are calculated to present the thermodynamic behavior. For magnetic property, the magnetization and magnetic susceptibility are discussed at different temperature upon different magnetic field. The antiferromagnetic order is confirmed to be the ground state of the system, and it can be destroyed by a large magnetic field.


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