• Title/Summary/Keyword: SURFACE CRYSTALLIZATION

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Relationship between Pinned Wall Behavior and Surface Crystallization in Cobalt-rich, Near-zero Magenetostricitve Sensors (자왜계수가 0인 Co계 센서의 자벽의 자벽 고착거동과 표면 결정화간의 관계)

  • 김창경;유춘근
    • Journal of the Korean institute of surface engineering
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    • v.31 no.4
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    • pp.199-208
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    • 1998
  • 자벽고착 개념에 기초를 둔 새로운 조화센서는 다음과 같이 설명되어진다. 2단계 열처리된 Co계 비전질 percursor은 특이한 signal을 유발시키는데 이는 자속의 단계적인 변화를 나타내는 hystresisloop에 기인한다. 자장하에서의 1단계 열처리는 M-H loop에서 일축유도 자기이방성을 발생시킨다. 2단계 무자장하의 열처리는 고착된 자벽의 stepped hystresis의 특성을 나타내는데 이로인해 유용한 marker로서의 특징을 가지게 된다. 열처리동안 비정질재료의 표면과 내부에서 상당량의 산화와 결정화 과정을 거치는 것이 관찰되었다. 이오인한 표면 자벽 고착 모델의 제안은 자벽의 고착이 비정질부분과 semi-hard Co 층간의 접합면에서 가장 효과적으로 얻어지다는 것으로써 확신되어진다. 또한 자벽 고착 자장과 결정화된 Co층의 두께간의 상당한 연관성도 관찰되었다.

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An-isotropic Corrosion Behavior of A Marine Steel with Cold Rolling

  • Yang, So E.;Song, Churl H.;Choi, Ga Yeon;Choi, Yong;Choe, Jin I.;Jung, Hwan G.;Kho, So W.;Lee, Chang S.
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2012.05a
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    • pp.330-330
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    • 2012
  • Microstructure of a marine steel with a modified AISI-1004 composition was controlled by cold rolling and heat treatment, which corrosion behavior in an artificial sea water was electrochemically determined for the each deformation direction. The lowest corrosion rate of the surface normal to the rolling direction is related t the (111) fiber structure. Additional annealing at $550^{\circ}C$ for 24 hours improves the corrosion rate which is related to re-crystallization and reduction of (111) concentration.

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Influence of surface roughness of ZnO layer on the growth of polycrystalline Si layer via aluminum-induced layer exchange process

  • Choi, Sung-Kuk;Chang, Won-Beom;Jung, Soo-Hoon;Hara, Kosuke;Watanabe, Haruna;Usami, Noritaka;Chang, Ji-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.8
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    • pp.692-697
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    • 2016
  • This study investigated the effect of surface roughness of zinc oxide (ZnO) layer on the growth of polycrystalline Si layer via an Al-induced layer exchange process. It was found that the growth rate, grain size, crystallization fraction, and preferential orientation of the polycrystalline Si layer were strongly influenced by the surface roughness of the underlying ZnO layer. As the roughness of the ZnO surface increased, a higher growth rate (~40 min) and preferential Si (100) orientation were obtained because of the spatial concentration fluctuations in the Al-Si alloy, induced by the surface roughness of the underlying ZnO layer.

Fabrication of Poly Seed Layer for Silicon Based Photovoltaics by Inversed Aluminum-Induced Crystallization (역 알루미늄 유도 결정화 공정을 이용한 실리콘 태양전지 다결정 시드층 생성)

  • Choi, Seung-Ho;Park, Chan-Su;Kim, Shin-Ho;Kim, Yang-Do
    • Korean Journal of Materials Research
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    • v.22 no.4
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    • pp.190-194
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    • 2012
  • The formation of high-quality polycrystalline silicon (poly-Si) on relatively low cost substrate has been an important issue in the development of thin film solar cells. Poly-Si seed layers were fabricated by an inverse aluminum-induced crystallization (I-AIC) process and the properties of the resulting layer were characterized. The I-AIC process has an advantage of being able to continue the epitaxial growth without an Al layer removing process. An amorphous Si precursor layer was deposited on Corning glass substrates by RF magnetron sputtering system with Ar plasma. Then, Al thin film was deposited by thermal evaporation. An $SiO_2$ diffusion barrier layer was formed between Si and Al layers to control the surface orientation of seed layer. The crystallinity of the poly-Si seed layer was analyzed by Raman spectroscopy and x-ray diffraction (XRD). The grain size and orientation of the poly-Si seed layer were determined by electron back scattering diffraction (EBSD) method. The prepared poly-Si seed layer showed high volume fraction of crystalline Si and <100> orientation. The diffusion barrier layer and processing temperature significantly affected the grain size and orientation of the poly Si seed layer. The shorter oxidation time and lower processing temperature led to a better orientation of the poly-Si seed layer. This study presents the formation mechanism of a poly seed layer by inverse aluminum-induced crystallization.

A Study on Characteristics of Tin-doped Indium Oxide Film for Polyethersulfone Flexible Substrate by Low Temperature E Beam Deposition Process (저온 E Beam 증착 공정으로 제조된 폴리에테르설폰 유연기판용 ITO 필름 특성 연구)

  • Rhew, Ju-Min;Kang, Ho-Jong
    • Polymer(Korea)
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    • v.36 no.3
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    • pp.393-400
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    • 2012
  • The characteristics of indium tin oxide (ITO) thin film deposited on polyethersulfone (PES) film by low temperature E beam has been studied for the flexible photovoltaic devices. It was found that the substrate temperature in the deposition process affected the crystallization behavior of ITO during the post low temperature annealing process. Higher substrate temperature resulted in the increase of crystallinity of annealed ITO. Consequently, the lowering of sheet resistivity and better transmittance were obtained. Crystallization of ITO during the annealing process was facilitated by using oxygen gas in the deposition process and resulted in the enhancement on sheet resistivity and transmittance of ITO. The surface roughness of PES film prohibited the crystallization of ITO during the annealing process and it caused the increase of sheet resistivity and the decrease of transmittance of ITO.

Crystal growing of sodium type 13X zeolite by continuous crystallization method (연속결정화 방법에 의한 13X 제올라이트 결정성장)

  • 김익진;이해진;서동남
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.12 no.4
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    • pp.190-195
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    • 2002
  • NaX zeolite crystals of a uniform particle size of 50 $\mu$m were grown by continuous crystallization method from seed crystals (10~20 $\mu$m) added into a 0.5~2.0 g mother liquor having a composition $3.5Na_2O : Al_2O_3: 2.1SiO_2: 1000H_2O$. In order to investigate the crystal growing by continuous method, the mother solution was supplied after 7 days, 5 days, 3 days and 1 day, respectively. The seeding resulted in an increase in the fraction of large crystals compared with unseeded batches and successfully led to an uniform NaX zeolite crystal. It was postulated that the seeding in the synthesis mixture leaded out increase of surface area for physical contact reaction and directed growth of seed crystal without the nucleation in the synthesis gel.

Microstructure and Ferroelectric Properties of Randomly Oriented Polysrystalline $(Bi,Nd)_4Ti_3O_{12}$ Thin Films Prepared by Sol-Gel Method (졸-겔법으로 증착된 $(Bi,Nd)_4Ti_3O_{12}$ 박막의 미세구조와 강유전성에 대한 연구)

  • Kang, Dong-Kyun;Kim, Byong-Ho
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2007.06a
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    • pp.296-296
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    • 2007
  • Ferroelectric neodymium-substituted $Bi_4Ti_3O_{12}$(BTO) thin films have been successfully deposited on Pt/Ti/$SiO_2$/Si substrate by a sol-gel spin-coating process and the effect of crystallization temperature on their microstructure and ferroelectric properties were studied systematically. $Bi(TMHD)_3$, $Nd(TMHD)_3$, $Ti(O^iPr)_4$ were used as the precursors, which were dissolved in 2-methoxyethanol. The thin films were annealed at various temperatures from 600 to $720^{\circ}C$ in oxygen ambient for 1 hr, which was followed by post-annealed for 1 hr after depositing a Pt electrode to enhance the electrical properties. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to analyze the crystallinity and surface morphology of layered perovskite phase, respectively. The crystallinity of the BNT films was improved and the average grain size increased as the crystallization temperature increased from 600 to $720^{\circ}C$ at an interval of $40^{\circ}C$. The polarization values of the films were a monotonous function of the crystallization temperature. The remanent polarization value of the BNT thin films annealed at $720^{\circ}C$ was $24.82\;{\mu}C/cm^2$ at an applied voltage of 5 V.

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Effects of post-annealing and seeding layers on electrical properties of PLT thin films by MOCVD using ultrasonic spraying (후열처리 및 seeding 층이 초음파분무 MOCVD법에 의한 PLT 박막 제조 시 전기적 특성에 미치는 영향)

  • 이진홍;김기현;박병옥
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.12 no.5
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    • pp.247-252
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    • 2002
  • $(Pb_{1-x}La_x)TiO_3$ (x = 0.1) thin films were prepared on ITO-coated glass substrates by metal organic chemical vapor deposition using ultrasonic spraying. Effects of the post-annealing and the seeding layer on crystallization, microstructures and electrical properties of thin films were investigated. Dielectric constants of films increased due to the modification of crystallization and the changing of a surface morphology by applying the post-annealing. In addition, as the application of PT seed- ing layer offered nucleation sites to PLT thin films, electrical properties of films were enhanced by the increase of crys-tallinity and grain size. The dielectric constant of the films post-heated for 60 min and with a seeding layer was 213 at 1 kHz.