Synthesis and Characterization of Indium Oxide Doped Hematite xIn2O3·(1-x)α-Fe2O3 Solid Solution

2011 ◽  
Vol 1309 ◽  
Author(s):  
Monica Sorescu ◽  
Tianhong Xu ◽  
Lucian Diamandescu
Keyword(s):  
Solid Solution ◽  
Ball Milling ◽  
Indium Oxide ◽  
Milling Time ◽  
Mechanochemical Activation ◽  
Synthesis And Characterization ◽  
Quadrupole Split ◽  
Grain Sizes ◽  
Ball Milling Time

ABSTRACTIndium oxide-doped hematite xIn2O3·(1-x)α-Fe2O3 (x = 0.1-0.7) solid solution systems were synthesized using mechanochemical activation. The microstructures, magnetic and thermal properties of the system were dependent on In2O3 molar concentration x and ball milling time. XRD results showed that the completion of In3+ substitution of Fe3+ in hematite lattice occurs after 12 h ball milling for x = 0.1. For x = 0.3, 0.5 and 0.7, the substitutions between In3+ and Fe3+ into hematite and In2O3 lattices occur simultaneously. The lattice parameters of hematite and In2O3 vary as a function of ball milling time. The change in these parameters was due to ions substitution between In3+and Fe3+ and the decrease in grain sizes. Mössbauer spectra of the system with x = 0.3 were fitted with three sextets and two quadrupole-split doublets after milling, representing In3+ substitution of Fe3+ in hematite lattice and Fe3+ substitution of In3+ in two different sites of In2O3 lattice. TGA results showed that the hematite decomposition is enhanced due to the smaller hematite grain size. The crystallization of hematite and In2O3 was suppressed with the drops of enthalpy values due to the stronger solid-solid interactions after ball milling. These caused gradual In3+-Fe3+ substitution in hematite/In2O3 lattices.

Surface Characterization of the Milled–Silicon Nitride Nano Powders by XPS and TEM

2006 ◽  
Vol 326-328 ◽  
pp. 409-412
Author(s):  
Dae Chul Park ◽  
Toyohiko Yano ◽  
Sae Hoon Kim ◽  
Won Youl Choi ◽  
Jung Hee Cho
Keyword(s):  
Silicon Nitride ◽  
Ball Milling ◽  
Oxide Layer ◽  
Surface Characterization ◽  
Milling Time ◽  
Milling Process ◽  
Chemical State ◽  
Si3n4 Powder ◽  
Ball Milling Time

We studied the surface characterization of milled–silicon nitride nano-powders by XPS and TEM. The change of the chemical state and morphology of the oxide layer on the surface of Si3N4 nano-particles before and after a conventional wet–ball–milling process are investigated by X–ray photoelectron spectroscopy for measuring the chemical state of the oxide layer and transmission electron microscopy for observing surface morphology. The native oxide layers of as-received Si3N4 powders confirmed by HREM observation and their chemical states were different each other. As increasing ball–milling time, the chemical composition and the volume of oxide layer in Si3N4 powders were changed. The chemical state of as–received Si3N4 powder was near to SiO2 phase. After ball–milling process for long time, that of the milled Si3N4 powder shifted to Si2N2O phase. As increasing ball-milling time, the oxide layer of Si3N4 powder was also increased.

Structural, Magnetic and Hyperfine Properties of Molybdenum Dioxide-Hematite Mixed Oxide Nanostructures

MRS Advances ◽  
2018 ◽  
Vol 3 (47-48) ◽  
pp. 2887-2892
Author(s):  
Richard Trotta ◽  
Felicia Tolea ◽  
Mihaela Valeanu ◽  
Lucian Diamandescu ◽  
Agnieszka Grabias ◽  
...  
Keyword(s):  
Ball Milling ◽  
Milling Time ◽  
Mechanochemical Activation ◽  
Magnetic Measurements ◽  
Activation Process ◽  
Zero Field ◽  
Molybdenum Dioxide ◽  
Nanoparticle System ◽  
Ball Milling Time ◽  
Field Cooling

ABSTRACTMoO2-Fe2O3 nanoparticle system was successfully synthesized by mechanochemical activation of MoO2 and α-Fe2O3 equimolar mixtures for 0-12 hours of ball milling time. The study aims at exploring the formation of magnetic oxide semiconductors at the nanoscale. X-ray powder diffraction (XRD), Mössbauer spectroscopy and magnetic measurements were used to study the phase evolution of MoO2-Fe2O3 nanoparticle system under the mechanochemical activation process. The Mössbauer studies showed that the spectrum of the mechanochemically activated composites evolved from a sextet for hematite to sextet and a doublet upon duration of the milling process with molybdenum dioxide. Recoilless fraction was determined using our dual absorber method and was found to decrease with increasing ball milling time. Magnetic measurements recorded at 5 and 300 K in an applied magnetic field of 50,000 Oe showed the magnetic properties in the antiferromagnetic and canted ferromagnetic states. The Morin transformation was evidenced by zero-field cooling-field cooling (ZFC-FC) measurements in 200 Oe and the transformation characteristic temperatures were shifted to lower values.

Behavior of Graphite and Graphene under Mechanochemical Activation with Hematite and Magnetite Nanoparticles

MRS Advances ◽  
2018 ◽  
Vol 4 (3-4) ◽  
pp. 155-162
Author(s):  
Monica Sorescu ◽  
Mark Allwes
Keyword(s):  
Ball Milling ◽  
Magnetite Nanoparticles ◽  
Milling Time ◽  
Mechanochemical Activation ◽  
Carbon Clusters ◽  
Hyperfine Parameters ◽  
Quadrupole Split ◽  
Iron Carbides ◽  
Recoilless Fraction ◽  
Phase Sequence

ABSTRACTEquimolar mixtures of graphene and iron oxide nanoparticles were subjected to mechanochemical activation. The phase sequence was investigated using Mӧssbauer spectroscopy as function of ball milling time. For low milling times (2-4 hours) the series with hematite (Fe2O3) nanoparticles was fitted with 2 sextets, corresponding to hematite with carbon introduced in the lattice. At high milling times (8-12 hours) the same series exhibited an additional sextet with hyperfine parameters characteristic to iron carbides and a quadrupole-split doublet, which could be assigned to carbon clusters with small amounts of iron in them. The series with magnetite nanoparticles (Fe3O4) at low milling times was analyzed considering 2 sextets, corresponding to the tetrahedral and octahedral sites of magnetite. At high milling times, the magnetite series also exhibited a broad sextet representing iron carbides and the doublet associated with iron-containing carbon clusters. Supporting information was obtained by determinations of the recoilless fraction. The results were compared with those obtained by ball milling graphite with hematite and magnetite nanoparticles.

Carbon-Substituted Hematite and Magnetite Nanoparticles

MRS Advances ◽  
2015 ◽  
Vol 1 (3) ◽  
pp. 221-226
Author(s):  
Monica Sorescu ◽  
Richard Trotta
Keyword(s):  
Ball Milling ◽  
Magnetite Nanoparticles ◽  
Ultrafine Particles ◽  
Milling Time ◽  
Magnetic Hyperfine Field ◽  
Quadrupole Split ◽  
Recoilless Fraction ◽  
Tetrahedral Sites ◽  
Milled Sample ◽  
Ball Milling Time

ABSTRACTGraphite-doped hematite and magnetite nanoparticles systems (∼50 nm) were prepared by mechanochemical activation for milling times ranging from 2 to 12 hours. Their structural and magnetic properties were studied by 57Fe Mössbauer spectroscopy. The spectra corresponding to the hematite milled samples were analyzed by considering two sextets, corresponding to the incorporation of carbon atoms into the iron oxide structure. For ball milling time of 12 hours a quadrupole split doublet has been added, representing the contribution of ultrafine particles. The Mössbauer spectra of graphite-doped magnetite were resolved considering a sextet and a magnetic hyperfine field distribution, corresponding to the tetrahedral and octahedral sublattices of magnetite, respectively. A quadrupole split doublet was incorporated in the fitting of the 12-hour milled sample. The recoilless fraction for all samples was determined using our previously developed dual absorber method. It was found that the recoilless fraction of the graphite-doped hematite nanoparticles decreases as function of ball milling time. The f factor of graphite-containing magnetite nanoparticles for the tetrahedral sites stays constant, while that of the octahedral sublattice decreases as function of ball milling time. These findings reinforce the idea that carbon atoms exhibit preference for the octahedral sites of magnetite.

Synthesis and characterization of indium oxide-hematite magnetic ceramic solid solution

2011 ◽  
Vol 199 (1-3) ◽  
pp. 365-386 ◽  
Author(s):  
Monica Sorescu ◽  
Tianhong Xu ◽  
Lucian Diamandescu ◽  
Devin Hileman
Keyword(s):  
Solid Solution ◽  
Indium Oxide ◽  
Synthesis And Characterization ◽  
Ceramic Solid Solution

Experimental Investigation and Micro-Structural Evolution Analysis of CNT & Fly Ash Reinforced Aluminium Matrix Composites

2015 ◽  
Vol 830-831 ◽  
pp. 429-432 ◽  
Author(s):  
Udaya ◽  
Peter Fernandes
Keyword(s):  
Mechanical Properties ◽  
Experimental Investigation ◽  
Fly Ash ◽  
Ball Milling ◽  
Milling Time ◽  
Structural Evolution ◽  
Matrix Composites ◽  
Evolution Analysis ◽  
Ball Milling Time ◽  
Al Matrix

The paper illustrates Carbon nanotubes reinforced pure Al (CNT/Al) composites and fly ash reinforced pure Al (FA/Al) composites produced by ball-milling and sintering. Microstructures of the fabricated composite were examined and the mechanical properties of the composites were tested and analysed. It was indicated that the CNTs and fly ash were uniformly dispersed into the Al matrix as ball-milling time increased with increase in hardness.

Synthesis and Characterization of CNT Reinforced AA4032 Nanocomposites by High Energy Ball Milling

2010 ◽  
Author(s):  
M. S. Senthil Saravanan ◽  
K. Sivaprasad ◽  
S. P. Kumaresh Babu ◽  
P. Susila ◽  
B. S. Murty ◽  
...  
Keyword(s):  
Ball Milling ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Synthesis And Characterization ◽  
Energy Ball
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