Microwave-assisted solution synthesis, microwave sintering and magnetic properties of cobalt ferrite

Fariñas, Juan C.; Moreno, Rodrigo; Pérez, Aritz; García, M. A.; Garcı́a-Hernández, M.; Salvador, M. D.; Borrell, Amparo

doi:10.1016/j.jeurceramsoc.2017.12.052

Cited by 71 publications

(25 citation statements)

References 47 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…In general, industrial microwave frequency is 2.45 GHz or 915 MHz [27,36]. However, most of the experiments regarding materials [27,28,37,38], metallurgical properties [27,30], or food [36,39] processing by microwaves are based on microwave magnetrons with 2.45 GHz frequency [28]. Therefore, the frequency of the microwave was selected as 2.45 GHz in this work.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Deng

Zhang

et al. 2019

Processes

View full text Add to dashboard Cite

With the growth of the use of carbon fiber-reinforced polymer (CFRP) in various fields, the recovery of carbon fibers from CFRP waste is becoming a significant research direction. In the present work, degrading epoxy resin and recycling carbon fibers from CFRP waste by microwave thermolysis and traditional thermolysis were studied. The carbon fibers were successfully recovered by thermolysis under an oxygen atmosphere in this study. The properties of the recovered carbon fibers were characterized by field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), and Raman spectroscopy. The result shows that using microwave thermolysis to recover carbon fibers from CFRP waste is an attractive prospect. Compared to the traditional method, the reaction time was reduced by 56.67%, and the recovery ratio was increased by 15%. Microwave thermolysis is faster, more efficient, requires less energy, and obtains cleaner recovered carbon fibers than those recovered using traditional thermolysis.Processes 2019, 7, 207 2 of 12 including mechanical processes [14,15], chemical methods [4,[16][17][18][19][20], and thermal technology [3,[21][22][23]. However, long carbon fibers are difficult to obtain using a mechanical process, and their mechanical properties are seriously damaged with this technique [24,25]. Liu et al. [13], Yildirir et al. [19], and Hyde et al. [20] have investigated recycling carbon fibers from CFRP using different solvents under subcritical or supercritical conditions. These methods are expensive, difficult to industrialize, and produce large amounts of liquid waste and hazardous gases [1]. Yang et al. [3], López et al. [22], and Ye et al. [23] have studied thermolysis methods of recovering carbon fibers from CFRP. The pyrolysis process is not very economical, producing multiple hazardous gases and depositing char on the carbon fiber surfaces [1,19,25]. Therefore, research to develop new methods of recovering carbon fibers from CFRP has begun.Microwave heating is gradually being used more often in the area of material processing due to its advantages of rapid, uniform, and selective heating [26]. Microwave heating is the process of coupling materials with microwaves, absorbing electromagnetic energy and transforming it into heat within the material volume, in which the heat is generated from the inside to the entire volume [27][28][29]. Therefore, the microwave method can treat uniform samples due to its features of volumetric and internal heating [30,31]. Yingguang Li et al. [32,33] have reported curing of CFRP by microwave energy, and CFRP can absorb microwave energy and be heated effectively. This study provides a great reference for microwave applications in the preparation and recovery of CFRP. Long Jiang et al. [34] reported that microwave irradiation is a flexible, easy-to-control, efficient method to recover high-value carbon fibers, and recovered carbon fibers could be directly used as reinforcement in new polymers (Polypropylene and nyl...

show abstract

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Deng

Zhang

et al. 2019

Processes

View full text Add to dashboard Cite

show abstract

“…This is due to the loss of a characteristic different from the grain boundaries and the significant reduction in the ponderomotive force. 32,33 For the FC ceramic samples, the slight decrease in the lattice parameter, only at high temperatures (1250°C), may be primarily attributed to the valence change of ferric ions. The diffraction peaks of the sintered samples become narrow, which is attributed to the grain growth during the microwave sintering process, mainly for the FC ceramic.…”

Section: Resultsmentioning

confidence: 97%

“…The decrease in the cell parameter can also be associated with the change of Fe 3+ ions (0.064 nm) to ions Fe 2+ (0.076 nm), which has a higher ionic radius. 32,33 For the FC ceramic samples, the slight decrease in the lattice parameter, only at high temperatures (1250°C), may be primarily attributed to the valence change of ferric ions.…”

Section: Resultsmentioning

confidence: 97%

Effect of the CoFe₂O₄ initial particle size when sintered by microwave on the microstructural, dielectric, and magnetic properties

Perdomo

Zabotto

Garcia

et al. 2019

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

The particle size of CoFe2O4 powders (average particle size of 350 nm) was reduced to 50 nm by high‐energy milling. In this paper, special attention was given for analyzing the densification and grain growth of both particle sizes (350 and 50 nm) subject to ultrafast sintering assays using microwave sintering and their effect on the magnetic and electric properties. The results indicated that the grain growth was 10 times higher for the nanoparticle system, reaching similar sizes of ~1 μm in both cases after sintering. The relative density values were higher (95%) in the nanoparticle system due to the wide distribution of particle sizes generated in the grinding process. Qualitatively inferred microscopy analysis showed high sinterability of fine particles with a narrow distribution of grain size when subjected to ultrafast firing processes. Magnetization measurements at room temperature clearly show the reduction of Hc with increasing grain size. Electric resistivity, dielectric constant (ε′), and dielectric loss tangent (tan δ) were measured as a function of frequency at room temperature. The low values of dielectric constant (ε′) and dielectric loss (tan δ) in the low frequency range, shown for all samples sintered by microwave, prove the excellent uniformity in the microstructure.

show abstract

“…Owing to its excellent capabilities to produce mono‐disperse fine particles, nano‐crystalline and novel physical properties, the microwave‐assisted process has been extensively employed in synthesizing nanoparticles. Many publications on nanoparticle formation using microwave‐assisted techniques can be found in the literature in the last 10 years . These reflect that nanoparticle formation assisted by microwave irradiation has gained its popularity as a better approach than the conventional heating‐assisted process due to its rapid heating, shorter crystallization time, higher yield and purity, homogeneous nucleation, and more environmentally friendly, energy efficient and cost‐effective process .…”

Section: Introductionmentioning

confidence: 99%

Promoting Nucleation in Microwave‐Assisted Nanoparticle Synthesis Using Combined Two‐Stage Irradiation and Anti‐Solvent Addition

Shibatani

Matsumura

Asakuma

et al. 2019

Crystal Research and Technology

View full text Add to dashboard Cite

Microwave is advantageous for nanoparticle synthesis because nanostructured crystals and mono-dispersed nanoparticle size can be obtained due to the rapid growth induced by quick thermal response. In previous studies, it has been confirmed that an individual application of two-stage irradiation and anti-solvent addition is effective in promoting stable nucleation and smaller particle generation. Nevertheless, to date no studies have been reported in applying the two methods above simultaneously and examining their synergistic effect. This study, therefore, aims to investigate the possibility of producing finer particles using a stable operation without any superheating and abrupt bubble growth. From the experimental data, it is evident that the beneficial combined effect of two-stage irradiation and addition of anti-solvent on the stable finer nanoparticle formation could be observed and confirmed. It is expected that the findings and recommendations from this work may be useful in optimizing two-stage microwave-assisted nanoparticle synthesis with an addition of anti-solvent.

show abstract

Microwave-assisted solution synthesis, microwave sintering and magnetic properties of cobalt ferrite

Cited by 71 publications

References 47 publications

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Effect of the CoFe₂O₄ initial particle size when sintered by microwave on the microstructural, dielectric, and magnetic properties

Promoting Nucleation in Microwave‐Assisted Nanoparticle Synthesis Using Combined Two‐Stage Irradiation and Anti‐Solvent Addition

Contact Info

Product

Resources

About

Microwave-assisted solution synthesis, microwave sintering and magnetic properties of cobalt ferrite

Cited by 71 publications

References 47 publications

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Recycling of Carbon Fibers from CFRP Waste by Microwave Thermolysis

Effect of the CoFe2O4 initial particle size when sintered by microwave on the microstructural, dielectric, and magnetic properties

Promoting Nucleation in Microwave‐Assisted Nanoparticle Synthesis Using Combined Two‐Stage Irradiation and Anti‐Solvent Addition

Contact Info

Product

Resources

About

Effect of the CoFe₂O₄ initial particle size when sintered by microwave on the microstructural, dielectric, and magnetic properties