Control of crystalline texture in polycrystalline alumina ceramics by electrophoretic deposition in a strong magnetic field

2004 ◽  
Vol 19 (5) ◽  
pp. 1487-1491 ◽  
Author(s):  
T. Uchikoshi ◽  
T.S. Suzuki ◽  
H. Okuyama ◽  
Y. Sakka
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electric Fields ◽  
Electrophoretic Deposition ◽  
Alumina Powder ◽  
Layer By Layer ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
Polycrystalline Alumina ◽  
Seed Particles

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.

Orientation Control in Multilayered Alumina Prepared Using Electrophoretic Deposition in a Strong Magnetic Field

2007 ◽  
Vol 29-30 ◽  
pp. 223-226
Author(s):  
Tohru Suzuki ◽  
Tetsuo Uchikoshi ◽  
Koji Morita ◽  
Keijiro Hiraga ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electric Fields ◽  
Electrophoretic Deposition ◽  
Layer By Layer ◽  
Colloidal Processing ◽  
Orientation Control ◽  
Laminar Composites ◽  
Oriented Layer

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.

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
Keyword(s):  
Magnetic Field ◽  
Electrophoretic Deposition ◽  
Orientation Angle ◽  
Layer By Layer ◽  
Alumina Ceramics ◽  
X Ray Diffraction ◽  
Laminate Composites ◽  
Laminar Composites ◽  
The Magnetic Field ◽  
Oriented Layers

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.

Electrophoretic deposition of α-alumina particles in a strong magnetic field

2003 ◽  
Vol 18 (2) ◽  
pp. 254-256 ◽  
Author(s):  
Tetsuo Uchikoshi ◽  
Tohru S. Suzuki ◽  
Hideo Okuyama ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Diamagnetic Susceptibility ◽  
Aqueous Media ◽  
X Ray Diffraction ◽  
Single Crystalline ◽  
X Ray ◽  
Stable Suspension ◽  
Alumina Particles

The electrophoretic deposition of single-crystalline α-alumina particles dispersed in aqueous media was performed in a strong magnetic field of 10 T. The α-alumina particles in the stable suspension were aligned due to their anisotropic diamagnetic susceptibility and then deposited on a cathodic substrate. The orientation of the α-alumina crystallites was confirmed by x-ray diffraction of the sintered specimen.

Textured Beta-Sialon:Eu2+ Phosphor Deposits Fabricated by Electrophoretic Deposition (EPD) Process within a Strong Magnetic Field: Preparation Process and Photoluminescence (PL) Properties Depending on Orientation

2015 ◽  
Vol 654 ◽  
pp. 268-273
Author(s):  
Chen Ning Zhang ◽  
Tetsuo Uchikoshi ◽  
Li Hong Liu ◽  
Benjamin Dierre ◽  
Yu Jin Cho ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Magnetic Susceptibility ◽  
Electric Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Intensity Ratio ◽  
Preparation Process ◽  
Crystal Axis ◽  
Chromaticity Coordinates ◽  
The Magnetic Field

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.

Control of crystalline texture in polycrystalline TiO2 (Anatase) by electrophoretic deposition in a strong magnetic field

2006 ◽  
Vol 26 (4-5) ◽  
pp. 559-563 ◽  
Author(s):  
Tetsuo Uchikoshi ◽  
Tohru S. Suzuki ◽  
Shuji Iimura ◽  
Fengqiu Tang ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Tio2 Anatase

scholarly journals Thermoelectric properties of the (an-)isotropic QGP in magnetic fields

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
He-Xia Zhang ◽  
Jin-Wen Kang ◽  
Ben-Wei Zhang
Keyword(s):  
Magnetic Field ◽  
Seebeck Coefficient ◽  
Strong Magnetic Field ◽  
Landau Level ◽  
Electric Fields ◽  
Chemical Potential ◽  
Thermal Structure ◽  
Transport Coefficients ◽  
Transverse Motion ◽  
Thermoelectric Transport

AbstractThe Seebeck effect and the Nernst effect, which reflect the appearance of electric fields along x-axis and along y-axis ($$E_{x}$$ E x and $$E_{y}$$ E y ), respectively, induced by the thermal gradient along x-axis, are studied in the QGP at an external magnetic field along z-axis. We calculate the associated Seebeck coefficient ($$S_{xx}$$ S xx ) and Nernst signal (N) using the relativistic Boltzmann equation under the relaxation time approximation. In an isotropic QGP, the influences of magnetic field (B) and quark chemical potential ($$\mu _{q}$$ μ q ) on these thermoelectric transport coefficients are investigated. In the presence (absence) of weak magnetic field, we find $$S_{xx}$$ S xx for a fixed $$\mu _{q}$$ μ q is negative (positive) in sign, indicating that the dominant carriers for converting heat gradient to electric field are negatively (positively) charged quarks. The absolute value of $$S_{xx}$$ S xx decreases with increasing temperature. Unlike $$S_{xx}$$ S xx , the sign of N is independent of charge carrier type, and its thermal behavior displays a peak structure. In the presence of strong magnetic field, due to the Landau quantization of transverse motion of (anti-)quarks perpendicular to magnetic field, only the longitudinal Seebeck coefficient ($$S_{zz}$$ S zz ) exists. Our results show that the value of $$S_{zz}$$ S zz at a fixed $$\mu _{q}$$ μ q in the lowest Landau level (LLL) approximation always remains positive. Within the effect of high Landau levels, $$S_{zz}$$ S zz exhibits a thermal structure similar to that in the LLL approximation. As the Landau level increases further, $$S_{zz}$$ S zz decreases and even its sign changes from positive to negative. The computations of these thermoelectric transport coefficients are also extended to a medium with momentum-anisotropy induced by initial spatial expansion as well as strong magnetic field.

Grain-Orientation Control of Bi5FeTi3O15 Ceramics Prepared by Magnetic-Field-Assisted Electrophoretic Deposition Method

2008 ◽  
Vol 388 ◽  
pp. 205-208
Author(s):  
Muneyasu Suzuki ◽  
Tetsuo Uchikoshi ◽  
Yuji Noguchi ◽  
Masaru Miyayama
Keyword(s):  
Magnetic Field ◽  
Diffraction Analysis ◽  
Electrophoretic Deposition ◽  
Grain Orientation ◽  
Sintered Density ◽  
Deposition Method ◽  
X Ray Diffraction ◽  
Axis Orientation ◽  
Orientation Degree ◽  
X Ray

Magnetic-field-assisted electrophoretic deposition (B-assisted EPD) method has been applied for synthesizing a(b)-axis-oriented Bi5FeTi3O15 ceramics, and the effects of the B-assisted EPD on grain orientation and microstructures have been investigated. The sintering at 1100oC of the green compact obtained by the B-assisted EPD led to dense ceramics with a high relative sintered density of 98%. X-ray diffraction analysis shows that the a(b)-axis-orientation degree of the grain oriented ceramics evaluated by the Lotgering method was 45 %.

Orientation Control of Hematite via Transformation of Textured Goethite Prepared by EPD in a Strong Magnetic Field

2012 ◽  
Vol 507 ◽  
pp. 227-231 ◽  
Author(s):  
Tetsuo Uchikoshi ◽  
Tohru Suzuki ◽  
Yoshio Sakka
Keyword(s):  
Magnetic Field ◽  
Phase Transformation ◽  
Magnetic Property ◽  
Thermal Treatment ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Field Measurement ◽  
Magnetic Field Measurement ◽  
Crystalline Orientation ◽  
Orientation Control

Fabrication of textured hematite was achieved from paramagnetic goethite by electrophoretic deposition in a strong magnetic field followed by thermal treatment via topotactic phase transformation. The textured microstructure of the hematite was characterized by XRD and SEM observations. It was confirmed that the a,b-axes of the goethite were taken over the c-axis of the hematite through the topotactic phase transformation The magnetization vs magnetic field measurement using a VSM revealed that the textured hematite showed an anisotropic magnetic property depending on the direction of the crystalline orientation.

Electrophoretic Deposition of Ti3SiC2 and Texture Development in a Strong Magnetic Field

2012 ◽  
Vol 95 (9) ◽  
pp. 2857-2862 ◽  
Author(s):  
Mrinalini Mishra ◽  
Yoshio Sakka ◽  
Chungfeng Hu ◽  
Tohru S. Suzuki ◽  
Tetsuo Uchikoshi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Strong Magnetic Field ◽  
Electrophoretic Deposition ◽  
Texture Development
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