Design of Alumina/Alumina Laminate Composites with Crystalline-Orientated Layers Produced by Electrophoretic Deposition under a High Magnetic Field

2006 ◽  
Vol 314 ◽  
pp. 25-32
Author(s):  
Tetsuo Uchikoshi ◽  
Tohru Suzuki ◽  
Hideo Okuyama ◽  
Yoshio Sakka

Highly crystalline-textured alumina ceramics were fabricated by electrophoretic deposition (EPD) in a strong magnetic field of 12 T. Preferred orientation of the bulk was controlled by changing the direction of the applied electric field E relative to the magnetic field B during the EPD. Average orientation angle of the prepared monoliths as a function of the angle between the vectors E and B, ϕ B-E was estimated from the X-ray diffraction analysis. Alumina/alumina laminar composites with crystalline- oriented layers were also fabricated by alternately changing the ϕ B-E layer by layer during EPD in a magnetic field of 12 T.

2004 ◽  
Vol 19 (5) ◽  
pp. 1487-1491 ◽  
Author(s):  
T. Uchikoshi ◽  
T.S. Suzuki ◽  
H. Okuyama ◽  
Y. Sakka

Highly crystalline-textured pure dense alumina ceramics were fabricated from spherical alumina powder without any seed particles and sintering additives by electrophoretic deposition (EPD) in a strong magnetic field of 10 T. The crystalline texture was confirmed by x-ray diffraction (XRD) for alumina ceramics deposited at 10 T followed by sintering at 1873 K. The angle between the directions of the magnetic and electric fields (φB-E) was altered to control the dominant crystal faces of the α-alumina monoliths. The average orientation angles estimated from the XRD diagram of the samples prepared at φB-E = 0°, 45°, and 90° were 16.52°, 45.15°, and 84.90°, respectively. Alumina/alumina laminar composites with different crystalline-oriented layers were also fabricated by alternately changing the φB-E layer by layer during EPD in a 10 T magnetic field. It was demonstrated that by using this technique, it is possible to control the crystalline orientation by changing the angle of E versus B during the EPD.


2007 ◽  
Vol 29-30 ◽  
pp. 223-226
Author(s):  
Tohru Suzuki ◽  
Tetsuo Uchikoshi ◽  
Koji Morita ◽  
Keijiro Hiraga ◽  
Yoshio Sakka

We have reported that development of texture can be controlled by colloidal processing in a strong magnetic field followed by heating even for diamagnetic ceramics such as alumina, titania and so on. We demonstrate in this study that alumina/alumina laminar composites with different crystalline-oriented layer are produced by electrophoretic deposition (EPD) in a strong magnetic field. This composite was fabricated by alternately changing the angle between the directions of the magnetic and electric fields layer by layer during EPD in 12T. The grains in alternate layers are aligned differently.


2015 ◽  
Vol 654 ◽  
pp. 268-273
Author(s):  
Chen Ning Zhang ◽  
Tetsuo Uchikoshi ◽  
Li Hong Liu ◽  
Benjamin Dierre ◽  
Yu Jin Cho ◽  
...  

Beta-sialon:Eu2+ phosphor deposits were fabricated by electrophoretic deposition (EPD) process within a strong magnetic field (12 T). The direction of the magnetic field was adjusted to be parallel or perpendicular to that of the electric field, that is, vertical-or horizontal setup. The oriented deposits were fabricated by aligning the β-sialon:Eu2+ particles along the higher magnetic-susceptibility c-crystal axis (a, b-crystal plane). For the case of vertically-setup magnetic field, the oriented deposit aligned along the c-axis possessed higher relative deposit density than the randomly fabricated deposit, as a result, varying the intensity ratio of emission and transmitted excitation, and therefore, presenting different chromaticity coordinates; for the case of horizontally-setup magnetic field, photoluminescence (PL) intensities of the deposits oriented along c-axis were significantly improved by comparing with those of the randomly-oriented ones.


2007 ◽  
Vol 561-565 ◽  
pp. 1565-1568 ◽  
Author(s):  
Kazuhiko Iwai ◽  
Jun Akiyama ◽  
Shigeo Asai

A high magnetic field is a useful tool to control the crystal alignment of ceramic materials. In this study, a horizontal 10T static magnetic field was imposed on slurry containing hydroxyapatite (HAp) crystals under the horizontal mold rotation during slip casting process so as to introduce uni-axial alignment for some amount of crystals in the sample, and then it was sintered in atmosphere without the magnetic field. From X-ray diffraction, it has been found that the HAp crystals in the sample treated with the mold rotation under the magnetic field were aligned its c-axis to a particular direction.


2005 ◽  
Vol 19 (01n03) ◽  
pp. 651-653
Author(s):  
W. L. WANG ◽  
L. LI ◽  
K. J. LIAO ◽  
J. ZHANG ◽  
R. J. ZHANG ◽  
...  

The Magnetothermoelectric and thermoelectric power of nano- ZnO films was investigated. The ZnO films in this study were prepared by DC reactive sputtering using a Zn target (99.99%) containing AL of 1.5%. The films obtained were characterized by SEM, x-ray diffraction, optical and electrical measurements. It was found that the sputtering ZnO films were highly orientation growth with the c-axis perpendicular to the substrate surface. The measurements showed that there was a striking seebeck effect in the ZnO films, and their thermoelectric power was linearly increased with increasing temperature. The experimental results were also demonstrated that the thermoelectric power was degraded under the magnetic field. This finding may ascribe to the magneto resistive effect.


MRS Advances ◽  
2019 ◽  
Vol 4 (36) ◽  
pp. 1989-1999 ◽  
Author(s):  
Valery Sobol ◽  
Barys Korzun ◽  
Olga Mazurenko ◽  
Temirkhan Bizhigitov ◽  
Sabit Tomaev

ABSTRACTBismuth ferrite (BiFeO3) and La-, Nd- and Gd-substituted bismuth ferrite of the Bi1-xLaxFeO3, Bi1-xNdxFeO3, and Bi1-xGdxFeO3 types with the atomic part of the substitution element x equal up to 0.20 were synthesized by the solid-state reaction method using powders of oxides Bi2O3, Fe2O3, and La2O3, or Nd2O3, or Gd2O3 of pure grade quality and investigated using X-ray diffraction analysis. The magnetization was measured in the magnetic field up to 6.5⋅106 A/m at 5 and 300 K. It was found that the total substitution up to 0.20 atomic part of Bi by La, Nd, and Gd leads to the paramagnetic behavior of the doped bismuth ferrite at low temperatures in a wide range of magnetic field. Strong nonlinear dependence of magnetization on the magnetic field was detected and a ferromagnetic-like dependence of magnetization was observed for small magnetic fields. This can be explained by the exchange interaction between doping magnetic ions, as well as by the exchange interaction of these ions with ions of iron. The enhancement of magnetic properties with the increase of the content of the substitution is monotone and is more pronounced for the Bi1-xGdxFeO3 ceramics.


2018 ◽  
Vol 71 (11) ◽  
pp. 914
Author(s):  
Yanfang Xia ◽  
Min Liu ◽  
Duxin Li

Co0.76Cu0.74[Fe(CN)6]·7.5H2O was prepared as a powder by a chemical co-precipitation method. The powder X-ray diffraction patterns were indexed to the typical face-centred cubic structure with the lattice parameter a 10.55(2) Å. The temperature dependence of the χ−1 curve obeys the Curie–Weiss law (χ = C/(T – θ)) in the temperature range of 180–300 K. According to Curie–Weiss law, the calculated θ value is −54.82 K. In the paramagnetic state at 300 K, the effective magnetic moment (μeff = (8χT)1/2) is 3.58 μB per formula unit. The calculated theoretical effective magnetic moment is 4.06 μB. The magnetic field cooling measurements under a 200 Oe applied magnetic field show that the saturation magnetization value at 2 K of the complex Co0.76Cu0.74[Fe(CN)6]·7.5H2O is 1.528 emu g−1.


2014 ◽  
Vol 24 (3S1) ◽  
pp. 90-94 ◽  
Author(s):  
Le Tuan Tu ◽  
Luu Van Thiem ◽  
Pham Duc Thang

The magnetic properties in Co-Ni-P nanowires arrays with diameter of 200 nm were investigated. All the samples were prepared by electrodeposition method with pH of 5.5 and at room temperature. During the deposition, a magnetic field in range of 0 - 750 Oe was applied parallel to the wires axis. The crystalline structure and morphology of the samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The hysteresis loops were measured at room temperature using vibrating sample magnetometry (VSM). The mixture of hcp phases of the Co-Ni-P based nanowires has been indicated by the XRD pattern. The obtained results show that with 750 Oe magnetic field applied during deposition we can obtain maximum coercivity value (2180 Oe). The \(M_{r}/M_{s}\) ratio was rapid increased when the magnetic field changed from 0 Oe to 750 Oe.


2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Na-Yeong Hong ◽  
Hyunwoong Seo ◽  
Min-Kyu Son ◽  
Soo-Kyoung Kim ◽  
Song-Yi Park ◽  
...  

In this study, magnetic field (B) was applied on TiO2(anatase) of dye-sensitized solar cell (DSC) for alignment of crystal. Magnetic field was applied on TiO2when deposited TiO2on the fluorine tin oxide (FTO) was dried at 373 K for crystalline orientation. And applying time ofBwas varied 0~25 min. Characteristics of the magnetic field applied TiO2films were analyzed by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), and electrochemical impedance spectroscopy (EIS). Current-voltage characteristics were also analyzed using solar simulator, and it was confirmed that the energy conversion efficiency of 41% was increased. Finally, it was identified that the magnetic field affected orientation of TiO2, resulting in the enhancement of the performance of the DSC.


2007 ◽  
Vol 26-28 ◽  
pp. 563-565
Author(s):  
Kazuhiko Iwai ◽  
Manabu Usui ◽  
Shigeo Asai

A static magnetic field and an alternating current are imposed on a metallic alloy during solidification for a crystal alignment of the primary phase. A Sn-10%Pb is selected as a sample because its primary phase is expected to have an anisotropic nature in magnetic susceptibility. In the x-ray diffraction pattern of the sample solidified without the magnetic field, the first and second highest peaks are (101) and (211) planes. On the other hand, those solidified with the magnetic field are (200) and (220) planes which are magnetically preferred planes. That is, the primary phase crystals in the sample solidified with the magnetic field are aligned to the specific direction.


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