Fabrication and Magnetic Properties of Mullite Based Nanocomposites with Embedded FeCr Alloy Nanoparticles

2006 ◽  
Vol 510-511 ◽  
pp. 286-289
Author(s):  
Hao Wang ◽  
Wei Min Wang ◽  
Zheng Yi Fu ◽  
Tohru Sekino ◽  
Koichi Niihara
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Alloy Nanoparticles ◽  
Fecr Alloy ◽  
Acid Washing ◽  
Property Measurement ◽  
Nanocomposite Powders

Mullite-based nanocomposites with embedded FeCr alloy nanoparticles were synthesized by reduction of sol-gel prepared Al5.4(Fe0.8Cr0.2)0.6Si2O13 solid solution in hydrogen. The feature of the formation of FeCr alloy is characterized by XRD analysis. Structural characterization revealed that the intragranular FeCr alloy nanoparticles along with inter-granular iron grains were obtained in as reduced sample. After acid washing, the intergranular metal grains were eliminated. The static magnetic properties of nanocomposite powders were studied using Magnetic Property Measurement System. It is found that part of the intra-granular metal nanoparticles have superparamagnetic behavior at room temperature.

Microstructure and Properties of Mulite-FeCr Multifunctional Composite

2009 ◽  
Vol 66 ◽  
pp. 81-84
Author(s):  
Hao Wang ◽  
Wei Min Wang ◽  
Zheng Yi Fu
Keyword(s):  
Solid Solution ◽  
Solid Solutions ◽  
Structural Characterization ◽  
Hot Pressing ◽  
Alloy Nanoparticles ◽  
Multifunctional Composites ◽  
Ferromagnetic Properties ◽  
Fecr Alloy ◽  
Nanocomposite Powders ◽  
Properties Of Composites

Mullite-based FeCr multifunctional composites were prepared by reducing (Fe, Cr)-doped mullite solid solution powders with different Cr/Fe ratio and successively hot pressing. Structural characterization revealed that the dispersion of intragranular FeCr alloy nanoparticles and intergranular iron grains in mullite matrix was obtained in nanocomposite powders. Dense mullite-FeCr composites were fabricated from nanocomposite powders by sintering at 1650 °C. The microstructures, mechanical and ferromagnetic properties of composites were strongly affected by the Cr/Fe ratio in initial solid solutions.

scholarly journals Structure, optical and magnetic properties of new Bi0.5Na0.5TiO3- SrMnO3−δ solid solution materials

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Dang Duc Dung ◽  
Nguyen The Hung ◽  
Dorj Odkhuu
Keyword(s):  
Solid Solution ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Optical Band Gap ◽  
Electronic Devices ◽  
Sol Gel ◽  
Weak Ferromagnetism ◽  
Host Lattice ◽  
Ferroelectric Materials ◽  
Optical And Magnetic Properties

AbstractThe new Bi0.5Na0.5TiO3-SrMnO3−δ solid solution materials were fabricated via sol–gel method. The random incorporation of Sr and Mn cations into host lattice of Bi0.5Na0.5TiO3 resulted in structural distortion and influenced on the reduction of the optical band gap from 3.07 eV to 1.81 eV for pure Bi0.5Na0.5TiO3 and 9 mol% SrMnO3−δ solid solution into Bi0.5Na0.5TiO3. The magnetic properties of Bi0.5Na0.5TiO3 materials at room temperature were tuned via compensation of diamagnetic material with weak-ferromagnetism to ferromagnetism with low SrMnO3−δ content and combination of paramagnetism/antiferromagnetism-like and ferromagnetism with higher SrMnO3−δ content solid solution in Bi0.5Na0.5TiO3. The tunable magnetic and optical properties of lead-free ferroelectric materials was promising for their application to green electronic devices.

Effect of Annealing temperature on the Structural and Magnetic Properties of TbxY3-xFe5O12(x = 0.0, 1.0, 2.0) Thin Films Prepared by Sol-Gel Process

2012 ◽  
Vol 501 ◽  
pp. 236-241 ◽  
Author(s):  
Ftema W. Aldbea ◽  
Noor Bahyah Ibrahim ◽  
Mustafa Hj. Abdullah ◽  
Ramadan E. Shaiboub
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Vibrating Sample Magnetometer ◽  
X Ray ◽  
Garnet Phase ◽  
Sol Gel Process ◽  
Amorphous Structures

Thin films nanoparticles TbxY3-xFe5O12 (x=0.0, 1.0, 2.0) were prepared by the sol-gel process followed by annealing process at various annealing temperatures of 700° C, 800° C and 900° C in air for 2 h. The results obtained from X-ray diffractometer (XRD) show that the films annealed below 900°C exhibit peaks of garnet mixed with small amounts of YFeO3 and Fe2O3. Pure garnet phase has been detected in the films annealed at 900°C. Before annealing the films show amorphous structures. The particles sizes measurement using the field emission scanning electron microscope (FE-SEM) showed that the particles sizes increased as the annealing temperature increased. The magnetic properties were measured at room temperature using the vibrating sample magnetometer (VSM). The saturation magnetization (Ms) of the films also increased with the annealing temperature. However, different behavior of coercivity (Hc) has been observed as the annealing temperature was increased.

GROWTH, OPTICAL AND MAGNETIC PROPERTIES OF Co-DOPED TiO2 CRYSTAL

2011 ◽  
Vol 04 (03) ◽  
pp. 265-269 ◽  
Author(s):  
NAIFENG ZHUANG ◽  
RONGFENG WANG ◽  
XIAOLIN HU ◽  
CAIGEN SONG ◽  
BIN ZHAO ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Room Temperature ◽  
Grown Crystal ◽  
Reverse Flow ◽  
Optical Transmittance ◽  
Xrd Analysis ◽  
Rutile Phase ◽  
Czochralski Growth ◽  
Optical And Magnetic Properties ◽  
Co Doped

Co -doped TiO2 crystals (Co:TiO2) were grown by Czochralski growth (CZ) method and the edge-defined film-fed growth (EFG) method, respectively. Therein, EFG was an effective method to grow a higher quality Co:TiO2 crystal without the reverse flow of the melt. This as-grown crystal reaches a larger dimension of 10 mm × 15 mm × 18mm. XRD analysis confirms that as-grown crystal is isostructural with TiO2 rutile phase. Moreover, this crystal has ferromagnetism at room temperature and the magnetic moment of Co ion is 1.25 × 10-2 μB/Co . After annealed at 1273 K, Co:TiO2 crystal enhances obviously its optical transmittance, while this crystal shows diamagnetism due to the disappearance of the ferromagnetic signal.

scholarly journals FABRICATION AND PROPERTIES OF Co DOPED Bi0.5K0.5TiO3 – BiFeO3 SOLID SOLUTION

2018 ◽  
Vol 56 (1A) ◽  
pp. 197
Author(s):  
Nguyen Hoang Tuan
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Magnetic Properties ◽  
Crystal Structures ◽  
Solid Solutions ◽  
Sol Gel ◽  
Structure And Properties ◽  
Antiferromagnetic Ordering ◽  
Co Doped ◽  
Good Agreement

In this study, we present some results on the structure and properties of the solid solution of Bi0.5K0.5TiO3– BiFeCoO3 (BKT – BFCO) by Sol-gel method. Crystal structures of BKT – BFCO solid solutions were studies by XRD and Raman spectroscopy. The results were in good agreement with the previous reports of Bi0.5K0.5TiO3– BiFeO3 (BKT – BFO) and Bi0.5K0.5TiO3 – BiCoO3 (BKT – BCO) solid solutions. The magnetic properties were investigated via unsaturated M-H loop, which showed the competition of paramagnetic and antiferromagnetic ordering in BKT – BFCO. However, differing from the BKT – BFO and BKT – BCO solid solutions, the unclear values of saturated magnetism in BKT – BFCO raised the unexplained question, which needed further studies.

Lattice Expansion of BaCe0.54Zr0.36Y0.1O3-δ Ceramic Electrolyte

2020 ◽  
Vol 307 ◽  
pp. 149-153
Author(s):  
Nurul Waheeda Mazlan ◽  
Nafisah Osman ◽  
Oskar Hasdinor Hassan ◽  
Zakiah Mohamed
Keyword(s):  
Fuel Cell ◽  
Structural Analysis ◽  
Solid Oxide Fuel Cell ◽  
Room Temperature ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Solid Oxide ◽  
Lattice Expansion ◽  
Oxide Fuel ◽  
Ceramic Electrolyte

Abstract. Solid oxide fuel cell (SOFC) is an electrochemical conversion device that undergoes a thermal cycling at various operating temperature where lead to the degradation of its mechanical properties. Electrolyte among the main component in SOFC plays a crucial part in defined the overall performance which facing a lattice expansion event when exposed to heating. Thus, in this paper BaCe0.54Zr0.36Y0.1O3-δ (BCZY) was selected as potential electrolyte for intermediate temperature solid oxide fuel cell (IT-SOFC) to investigate its lattice expansion as a function of temperature. The sample was prepared via a sol gel method and calcined at 1100°C for 10 hours to form a powder and then pressed to become a pellet. To ensure a good densification in such pellet, two-steps sintering processes was indicated at 1500°C and ground to a powder form prior to the lattice expansion measurements. High temperature X-ray diffraction (HT-XRD) was used to study the lattice expansion of sample in the temperature range of 25°C to 700°C with interval 100°C under air atmosphere. HT-XRD analysis was done using X’pert Highscore Plus software and Visual for Electronic and Structural Analysis (VESTA) software was used to observe the crystal structure. Phase and structural analysis of BCZY electrolyte materials were discussed. Apparently, the BCZY shows an average of 97% phase purity from room temperature to 700°C. Rietveld refinement analysis revealed that the BaCe0.54Zr0.36Y0.1O3-δ exhibits cubic symmetrical structure with unit cell, a=b=c that varied from 4.3440Å - 4.3731Å for all the temperature studied. Thus, the expansion percentage for the lattice expansion from room temperature to 700°C was about 12.6 %.

scholarly journals Annealing and Ni content effects on EPR and structural properties of Zn1–xNixO aerogel nanoparticles

2017 ◽  
Vol 35 (3) ◽  
pp. 454-462
Author(s):  
A. Sayari ◽  
L. El Mir
Keyword(s):  
Raman Scattering ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
Sol Gel ◽  
Xrd Analysis ◽  
Processing Technique ◽  
Host Lattice ◽  
Nickel Concentration ◽  
Gravimetric Analysis ◽  
Ni Content

AbstractZn1-xNixO aerogel nanopowders with nickel concentration in the range of 0.05 ≤ x ≤ 0.25, were synthesized by the sol-gel processing technique and post-annealed in air at 500 °C. Structural, vibrational, thermal and magnetic properties of the as-prepared and annealed Zn1-xNixO powdered samples were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman scattering, thermal gravimetric analysis (TGA) and electron paramagnetic resonance (EPR) spectroscopy. In addition to the ZnNiO phase, XRD analysis revealed the formation of a secondary NiO phase when the Ni content was greater than or equal to 10 %. The TEM images confirm that the particle size is in the range of 20 nm to 40 nm, in accordance with XRD results, and the particles are well dispersed. Raman scattering measurements confirm the wurtzite structure of the synthesized Zn1-xNixO nanopowders and show that intrinsic host-lattice defects are activated when Ni2+ ions are substituted to the Zn sites. Room temperature ferromagnetic order was observed in all of the samples and was strongly dependent on the Ni content and thermal annealing. These results indicate that the observed room temperature ferromagnetism in ZnNiO may be attributed to the substitutional incorporation of Ni at Zn sites.

Properties and Microstructure of Mullite-Based Iron Nanocomposite

2006 ◽  
Vol 317-318 ◽  
pp. 611-614 ◽  
Author(s):  
Hao Wang ◽  
Tohru Sekino ◽  
Takafumi Kusunose ◽  
Tadachika Nakayama ◽  
Koichi Niihara
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Solid Solution ◽  
Iron Content ◽  
Room Temperature ◽  
Iron Nanoparticles ◽  
Sol Gel ◽  
Granular Structure ◽  
High Iron Content ◽  
Oxide Solid Solution

Mullite-based iron nanocomposites were prepared by the reduction of a mullite-iron oxide solid solution and successive hot pressing. The solid solution was obtained from the heat treatment of diphasic gel by sol-gel method. Some of the α-iron nanoparticles have an intra-granular structure just after reduction. Mechanical properties are strongly affected by the content of iron. Low iron content is beneficial to strengthening while high iron content can improve the fracture toughness. Furthermore, the nanocomposites also behave ferromagnetic properties at room temperature.

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