Synthesis of Carbon/Ferrite Composite by In-Situ Pressure Pyrolysis of Organometallic Polymers

1992 ◽  
Vol 274 ◽  
Author(s):  
Shin-Ichi Hirano ◽  
Toshinobu Yogo ◽  
Koichi Kikuta ◽  
Makoto Fukuda
Keyword(s):  
Coercive Force ◽  
Supercritical Water ◽  
Nickel Ferrite ◽  
Zinc Ferrite ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Organometallic Polymers ◽  
Nickel Zinc ◽  
Ferrite Particle

ABSTRACTFerrite particle-dispersed carbon composite were synthesized by in-situ pressure pyrolysis of organometallic polymers at temperatures from 500 to 700°C under 125 MPa. Magnetite-dispersed carbon composite could be prepared from 550 to 700°C at 125 MPa. Nickel and nickel zinc ferrite particles were dispersed in carbon matrices at 550°C and 500°C, respectively, under 125 MPa. The morphology of the carbon matrix can be controlled by the pyrolysis conditions and the amount of coexistent supercritical water. Carbon spherulites of several micrometers dispersed with ferrite particles less than 100 nm were successfully synthesized by pressure pyrolysis of organometallic polymers in the presence of supercritical water. The saturation magnetization of magnetite-, nickel ferrite- and nickel zinc ferrite-dispersed carbon were 74, 30 and 65 emu/g, respectively. The coercive force of nickel ferrite-dispersed carbon was about 200 Oe.

Synthesis of nickel zinc ferrite nanoparticle/organic hybrid from metalorganics

2007 ◽  
Vol 22 (7) ◽  
pp. 1967-1974 ◽  
Author(s):  
Yasuaki Hayashimto ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Zinc Ferrite ◽  
Oxide Particle ◽  
Organic Matrix ◽  
X Ray Diffraction ◽  
Organic Hybrid ◽  
Nickel Zinc ◽  
Ferrite Particle ◽  
Ferrite Nanoparticle ◽  
Hydrolysis Conditions

(Ni,Zn)Fe2O4 particle/organic hybrid was synthesized in situ from metalorganics below 100 °C. A mixture of nickel (II) acetylacetonate (NA), zinc acetylacetonate (ZA), and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding a spinel oxide particle/organic hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-ZA-IAA. Nanocrystalline nickel zinc ferrite particles below 5 nm were uniformly dispersed in the organic matrix. The magnetization of hybrid increased with an increasing amount of water for hydrolysis. Nano-sized nickel zinc ferrite particle/organic hybrid showed a magnetization-applied field (BH) curve with no remanence above 40 K. The magnetization versus H/T curves from 40 to 100 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.2 emu/g and 150 Oe, respectively, at 4.2 K. The absorption edge of the hybrid was blue-shifted compared with that of bulk ferrite.

In-situ reduction of ferrites

1984 ◽  
Vol 42 ◽  
pp. 420-421
Author(s):  
D.S. Tucker ◽  
J.R. Porter
Keyword(s):  
Direct Observation ◽  
Rate Control ◽  
Nickel Ferrite ◽  
Zinc Ferrite ◽  
Mixed Oxides ◽  
In Situ Reduction ◽  
Environmental Cell ◽  
Cation Ratio

An environmental cell equipped TEM can be used to observe gassolid reactions directly. In previous work, the hematite-magnetic reaction was studied by ‘in-situ’ HVEM. The direct observation of the nucleation of reduced phases and the development of porosity provided information to complement kinetic experiments. When mixed oxides, such as zinc ferrite and nickel ferrite, are reduced, cation segregation across the reduction interface can occur, with the possibility of rate control by the back segregation of one cation ahead of the reduction interface. An EDS capability allows changes in the cation ratio ahead of the reduction interface to be monitored after reduction.

scholarly journals A Fe/Fe3O4/N-carbon composite with hierarchical porous structure and in situ formed N-doped graphene-like layers for high-performance lithium ion batteries

2015 ◽  
Vol 44 (10) ◽  
pp. 4594-4600 ◽  
Author(s):  
Yao Li ◽  
Qing Meng ◽  
Shen-min Zhu ◽  
Zeng-hui Sun ◽  
Hao Yang ◽  
...  
Keyword(s):  
Lithium Ion Batteries ◽  
Porous Carbon ◽  
High Performance ◽  
Lithium Ion ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Hierarchical Porous Structure ◽  
Hierarchical Porous ◽  
Doped Graphene

A Fe/Fe3O4/N-carbon composite consisting of a porous carbon matrix containing a highly conductive N-doped graphene-like network and Fe/Fe3O4 nanoparticles was prepared.

In situ Synthesis of Nickel Ferrite Nanoparticle/organic Hybrid

2005 ◽  
Vol 20 (6) ◽  
pp. 1590-1596 ◽  
Author(s):  
Satoshi Nakamura ◽  
Wataru Sakamoto ◽  
Toshinobu Yogo
Keyword(s):  
Photoelectron Spectroscopy ◽  
Nickel Ferrite ◽  
Oxide Particle ◽  
Organic Matrix ◽  
X Ray ◽  
Organic Hybrid ◽  
Ferrite Particle ◽  
Ferrite Nanoparticle ◽  
Hydrolysis Conditions

A NiFe2O4 particle/organic hybrid was synthesized in situ from iron-organic and nickel organic compounds below 100 °C. A mixture of nickel (II) acetylacetonate (NA) and iron (III) 3-allylacetylacetonate (IAA) was hydrolyzed and polymerized yielding spinel oxide particle/oligomer hybrid. X-ray diffraction analysis revealed that the crystallinity of spinel particles was dependent upon the hydrolysis conditions of NA-IAA. Nanocrystalline nickel ferrite particles around 10 nm were uniformly dispersed in the organic matrix. The formation of nickel ferrite was confirmed by energy-dispersive x-ray and x-ray photoelectron spectroscopy. The saturation magnetization of hybrid increased with increasing water amount for hydrolysis. Nano-sized nickel ferrite particle/organic hybrid showed a BH curve with no remanence above 75 K. The magnetization versus H/T curves at 300, 200, and 75 K were superimposed on the same curve and satisfied the Langevin equation. The remanent magnetization and coercive field of the hybrid were 7.4 emu/g and 460 Oe, respectively, at 5 K.

The system of indicators of the quality of the carbon-carbon composite materials and technologies of their production

2018 ◽  
pp. 127-132
Author(s):  
T. N. Antipova ◽  
D. S. Shiroyan
Keyword(s):  
Composite Material ◽  
Low Cost ◽  
Experimental Studies ◽  
Carbon Matrix ◽  
Carbon Composite ◽  
Optimal Number ◽  
Laboratory Equipment ◽  
Carbon Composite Material ◽  
Carbon Composite Materials

The system of indicators of quality of carbon-carbon composite material and technological operations of its production is proved in the work. As a result of the experimental studies, with respect to the existing laboratory equipment, the optimal number of cycles of saturation of the reinforcing frame with a carbon matrix is determined. It was found that to obtain a carbon-carbon composite material with a low cost and the required quality indicators, it is necessary to introduce additional parameters of the pitch melt at the impregnation stage.

Effect of antisite formation on magnetic properties of nickel zinc ferrite particles

2013 ◽  
Vol 114 (18) ◽  
pp. 183903 ◽  
Author(s):  
B. Ghosh ◽  
M. Sardar ◽  
S. Banerjee
Keyword(s):  
Magnetic Properties ◽  
Zinc Ferrite ◽  
Nickel Zinc

Head-Wear Measurements by Autoradiography of the Worn Magnetic Tapes

1986 ◽  
Vol 108 (1) ◽  
pp. 22-28 ◽  
Author(s):  
B. Bhushan ◽  
G. W. Nelson ◽  
M. E. Wacks
Keyword(s):  
Magnetic Tape ◽  
Wear Debris ◽  
Zinc Ferrite ◽  
Tape Drive ◽  
Average Amount ◽  
Nickel Zinc ◽  
Total Head ◽  
Drive Component

The transfer of wear debris of a nickel-zinc ferrite head to a magnetic tape was measured by autoradiography of the tape after it was worn against the irradiated ferrite head. Ferrite deposits on the tape were observed only after 5000 passes. Dots or specks on the autoradiograph of the tapes of about 200 micrometers in diameter, caused by particles of ferrite about 1 μm in diameter and mass of about 10−11 g, were measured. The average amount of ferrite deposited on the tape after 20,000 passes was about 0.6 nanogram per square centimeter; some areas showed uniform deposits of ferrite concentration of 10–20 ng/cm2. Based on our estimates of total head wear, only a small fraction (about 0.6 percent) of the total ferrite wear debris was transferred to the tape, about 0.2 percent was transferred to the tape-drive component surfaces, and the rest, we conclude, was airborne.

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