• Title/Summary/Keyword: Micro-pulling-down method

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MICROSTRUCTURE AND HIGH TEMPERATURE MECHANICAL PROPERTIES OF SAPPHIRE/R-Al-O (R=Y,Gd,Er,Ho,Dy) EUTECTIC FIRES GROWN BY MICRO PULLING-DOWN METHOD

  • Hasegawa, K.;Yoshikawa, A.;Durbin, S.;Epelbaum, B.;Fjkuda, T.;Waku, Y.
    • Proceedings of the Korea Association of Crystal Growth Conference
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    • 1999.06a
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    • pp.403-418
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    • 1999
  • Fiber growth of Al2O3/R-Al-O(R=Y, Gd, Dy, Ho, Er) eutectic by the micro-pulling down methods is described. The thermal stability and strength at elevated temperature of each material is evaluated in relation to the microstructure. PACS: 81.05 Mh, 81.10 Fq, 81.30-t.

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Microstructure and high temperature mechanical properties of sapphire/R-Al-O(R = Y, Gd, Er, Ho, Dy) eutectic fibers grown by micro-pulling-down method

  • Hasegawa, K.;Yoshikawa, A.;Durbin, S.D.;Epellbaum, B.M.;Fukuda, T.;Waku, Y.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.9 no.4
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    • pp.432-436
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    • 1999
  • Fiber growth of $Al_{2}O_{3}/R-Al-O$ (R = Y, Gd, Dy, Ho, Er) eutectic by the micro-pulling down method is described. The thermal stability and strength at elevated temperature of each materials is evaluated in relation to the microstructure.

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Crystal Growth and Photoluminescence Property of Stoichiometric LiNbO3 Single Crystal Fiber by Addition of Nd2O3 (Nd\2O3 첨가에 따른 화학양론조성 LiNbO3 단결정의 성장 및 형광특성)

  • Shur, Joong-Won;Yoon, Seok-Gyu;Lee, Sung-Mun;Yoon, Dae-Ho
    • Journal of the Korean Ceramic Society
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    • v.39 no.10
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    • pp.977-980
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    • 2002
  • Using the micro-pulling down method, $Nd_2O_3$ doped crack-free stoichiometric $LiNbO_3$ single crystals were grown in 1 mm diameter and 30∼35 mm length. The homogeneous distributions of $Nd_2O_3$ concentration were confirmed by the electron probe micro analysis. The absorption and photoluminescence spectra were measured with respect to the $Nd_2O_3$ doping.

Micro-Porous Ceramics Using directionally $MgAl_2O_4/MgO$ eutectic crystals

  • Lee, Jong-Ho
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.15 no.6
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    • pp.229-233
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    • 2005
  • Novel process was tried to obtain micro-porous ceramic body containing continuous pore channel. $MgAl_2O_4/MgO$ eutectic fibers and rods have been grown successfully by the micro-pulling-down method, and the microstructures and optical characterizations of grown crystals were performed. $MgAl_2O_4/MgO$ eutectic fibers of $0.3{\sim}1mm$ in diameter and about 500 mm in length, and the rods having 5 mm in diameter with approximately 60 mm in length have been grown with the $6{\sim}120mm/hr$ of growth speed. The eutectic fibers showed homogeneous microstructure in which MgO fiber aligned to the growth direction in the $MgAl_2O_4$ (spinel) matrix. The grown crystals looked semitransparency under naked eyes. Optical and orientational characterizations were performed. The second phase of MgO (periclase) was easily removed by selective etching with hydrochloric acid, and then porous bodies were obtained.

Crystal growth and optical properties of Zn and Yb co-doped $LiNbO_3$ rod-shape single crystal by micro-pulling down method (Micro-pulling down법으로 성장시킨 Zn와 Yb를 첨가한 $LiNbO_3$ 단결정의 광학적 특성)

  • Her, J.Y.;Lee, H.J.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.19 no.1
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    • pp.11-14
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    • 2009
  • Yb and Zn co-doped $LiNbO_3$ single crystal rods which had a diameter of 2 mm and a length of $15{\sim}25 mm$ were grown by micro-pulling down (${\mu}-PD$) method. The single crystals were successfully grown and had a uniform diameter and a smooth surface without crack. We realized of $LiNbO_3$ single crystals were hexagonal structure to compare with peaks of $LiNbO_3$ powder by Raman spectra. The threshold level of Zn concentration which is effective for optical damage were observed as about 1 mol% with IR transmission spectra.

Crystal growth and optical properties of near-stoichiometric $Zn:LiNbO_3$ fiber single crystal by ${\mu}-PD$ method (${\mu}-PD$ 법으로 성장시킨 near-stoichiometric 조성 $Zn:LiNbO_3$ fiber 단결정 성장 및 광손상 특성)

  • Lee, H.J.;Shur, J.W.;Shin, T.I.;Song, W.Y.;Yoon, D.H.
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.16 no.6
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    • pp.235-239
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    • 2006
  • ZnO-doped near-stoichiometric $LiNbO_3$ single crystals of $0.8{\sim}1.0mm$ diameter and $30{\sim}35mm$ length were grown by the micro-pulling down (U-PD) method. The structure of the grown crystals was confirmed by powder x-ray diffraction (XRD) patterns. Electron probe micro analysis (EPMA) showed that Zn ions were homogeneously incorporated In grown crystals. The threshold in ZnO doping level was confirmed that an abrupt change in the features of $OH^-$ absorption band as doping level reaching about 2 mol%.

Growth $Al_2$O$_3$/ZrO$_2$eutectic fibers by the micro-pulling down method and its mechanical properties (Micro-pulling down법을 이용한 $Al_2$O$_3$/ZrO$_2$eutectic fiber의 제조 및 기계적 특성)

  • ;Akira Yoshikawa;Stephen D. Durbin;;Tsuguo Fukuda;Yoshiharu Waku
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.10 no.5
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    • pp.345-349
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    • 2000
  • $Al_2O_3/ZrO_2$eutectic fibers were grown by micro-pulling down technique and investigated their microstructure as a function of solidification rate. $Al_2O_3/ZrO_2$eutectic fibers 0.2~2 mm in diameter and 500 mm in length have been grown with a pulling rate of 0.1~15 mm/min. The eutectic microstructures changed as a function of fulling rate from rod-shaped to cellular shape containing some thin lamellar pattern via uniform lamellar structure. Typical lamellar thickness decreased from about 380 nm to 110 nm as the pulling rate increased from 1 mm/min to 15 mm/min. The interlamellar spacing fitted with the inverse-square-root dependence on pulling rate according to $\lambda$= $1{\times}v^{-1/2}$, where $\lambda$ has the dimension in $\mu\textrm{m}$ and v is $\mu\textrm{m}$/s. Hardness value reached 13.1 GPa at 15 mm/min of pulling rate and tensile strength 900 MPa at 10 mm/min were also increased as the interlamellar spacing decreased.

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Up-conversion Property of Er2O3 and MgO Co-doped Stoichiometric LiNbO3 Single Crystal by Using the μ-PD Method (μ-PD법을 이용하여 성장시킨 Er2O3와 MgO를 첨가한 화학양론조성 LiNbO3 단결정의 Up-conversion 특성)

  • Shur, Joong-Won;Jeon, Won-Nam;Lee, Sung-Mun;Yang, Woo-Seok;Lee, Han-Young;Yoon, Dae-Ho
    • Journal of the Korean Ceramic Society
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    • v.39 no.9
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    • pp.835-839
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    • 2002
  • Stoichiometric $LiNbO_3$(LN) single crystals of 1 mm diameter and 30∼40 mm length with co-doped the $Er_2O_3$ and MgO were grown by the Micro-Pulling Down(${\mu}$-PD) method. The grown crystals were investigated for the change of the up-conversion property by the $Er_2O_3$ and MgO addition and the optical damage by the MgO concentration. Also, the crystals were studied the defects using the optical microscope and it is identified the homogeneities of the distribution of the $Er_2O_3$ and MgO concentration by the Electron Probe Micro Analysis(EPMA).