• Title/Summary/Keyword: Sol

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Properties of Nano-Hybrid Coating Films Synthesized from Colloidal Silica-Silane (콜로이달 실리카와 실란으로부터 합성된 나노하이브리드 코팅 박막의 특성)

  • Na, Moon-Kyong;Ahn, Myeong-Sang;Kang, Dong-Pil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.232-233
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    • 2006
  • In recent years the interest in organic/inorganic hybrid materials has increased at a fast rate. Nano organic-inorganic hybrid composites have shown advantages for preparing hard coating layers. Especially, nano hybrid composite has low environmental pollution. It has high transparency, hardness, toughness, thermal dissociation temperature, hydrophobicity by using nano sized inorganic material. There are many ways in which these materials may be synthesized, a typical one being the use of silica and silanes using the sol-gel process. The structure of sol-gel silica evolves as a result of these successive hydrolysis and condensation reactions and the subsequent drying and curing. The sol-gel reactions are catalyzed by acids and produce silica sol solutions. The silica sol grows until they reach a size where a gel transition occurs and a solid-like gel is formed. Colloidal silica(CS)/silane sol solutions were synthesized in variation with parameters such as different acidity and reaction time. In order to understand their physical and chemical properties, sol-gel coating films were fabricated on glass. From all sol-gel solutions, seasoning effect of sol-gel coating layer on glass was observed.

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A Study on Preparation and Characterization of Mullite Coated Film by Sol-Gel Process (졸-겔법에 의한 Mullite 코팅막의 제조 및 특성에 관한 연구)

  • 이용택;최영우;양중식
    • Journal of the Korean Ceramic Society
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    • v.34 no.6
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    • pp.611-619
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    • 1997
  • Optimal Mullite sol was synthesized by sol-gel process using Aluminium sec-butoxide(ASB), Tetraethoxysilane(TEOS) and then, Mullite films were dip-coated with various holding time in sol bath and heat-treated at 130$0^{\circ}C$ above for crystallization. The thickness of coated film increased linearly with holding time in sol bath and average pore size was controllable within 20~30$\AA$.

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The Preparation of Alumina Fiber by Sol-gel Method: (II) Properties of Fiber Spun by TEA Complexed Sol (졸겔법에 의한 알루미나 섬유의 제조: (II) TEA 착체졸로부터 방사한 섬유의 특성분석)

  • 최용수;이해욱;이종혁;박용일;김창은
    • Journal of the Korean Ceramic Society
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    • v.32 no.9
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    • pp.995-1002
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    • 1995
  • The alumina fiber was obtained by extruding the TEA complexed polymeric sol, synthesized by the alkoxide sol-gel method, through nozzle. The purpose of this study was to investigate the properties of fiber spun by TEA complexed sol. The analysis of sol indicated that TEA was bonded at alkoxide precursor and the optimum molar ratio for spinning was 0.5 mole of TEA, 3 mole of H2O. The cross section of the fiber from circular nozzle was not circular but oval, which indicated that the shape of nozzle did not affect the shape of fiber. The diameter of the fiber was about 100 ${\mu}{\textrm}{m}$ in the state of dried gel fiber, 60${\mu}{\textrm}{m}$ in calcined fiber, and the tensile strength of the fiber calcined at 90$0^{\circ}C$ was 2.1$\times$108 Pa.

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Characterization of Ceramic Composite-Membranes Prepared by TEOS-PEG Coating Sol (TEOS-PEG계 Sol-Gel코팅에 의한 세라믹 분리 막의 제조 및 특성)

  • Kim, Tae-Bong;Choi, Se-Young;Kim, Goo-Dae
    • Journal of the Korean Ceramic Society
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    • v.42 no.3 s.274
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    • pp.165-170
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    • 2005
  • Sol-gel methods offer many advantages over conventional slip-casting, including the ability to produce ceramic membranes. They are purer, more homogeneous, more reactive and contain a wider variety of compositions. We produced ormosil sol using sol-gel process under various molecular weight of polymer species[polyethylene glycol(PEG)] in total system [Tetraethyl ortho silicate(TEOS)-polyethylene glycol(PEG)]. The properties of as-prepared ormosil sol such as viscosity and gelation time are characterized. Also, the ceramic membrane was prepared by dip-coating with synthetic sol and its microstructure was observed by scanning electron microscopy. The permeability and rejection efficiency of membrane for oil/water emulsion were evaluated as cross­flow apparatus. The ormosil sol coated membrane was easily formed by steric effect of polymer and it improved flux efficiency because infiltration into porous support decreased. Its flux efficiency was elevated about $200\;l/m^2h$ compared with colloidal sol coated membrane at point of five minutes from starting test.

Preparation of Alumina Sol Coated BOPP Composites and Their Gas Permeation Characteristics (Alumina Sol을 코팅한 BOPP 복합체의 제조 및 기체 투과 특성)

  • Hong, Seong-Uk;Oh, Jae-Won;Ko, Young-Deok;Song, Ki-Chang
    • Membrane Journal
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    • v.19 no.1
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    • pp.19-24
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    • 2009
  • Sol-gel process is relatively simple, easy to use, cheap to install, and results in thin coating layers with superior physical and gas barrier properties. Films coated by the sol-gel process can be used as insulating films or packaging films for foods, chemicals, drugs, and beverages, etc. In this study, alumina sol was synthesized from aluminum isopropoxide and silane coupling agent was added to make coating solutions. In addition, biaxially oriented polypropylene (BOPP) was coated using several alumina sol solutions and their oxygen permeabilities were measured. The experimental results indicate that in the best case, the oxygen permeability of coated film was reduced by 85% compared to that of pure BOPP.

Properties of Sol-gel Coating Materials Synthesized from Colloidal Silicas and Methyltrimethoxysilane (Colloidal Silica와 Methyltrimethoxysilane간의 졸겔반응으로 합성된 코팅제 특성 연구)

  • 강동필;박효열;안명상;이태희;명인혜;강귀태
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.9
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    • pp.967-972
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    • 2004
  • Hardness and surface property of coated gel materials are considerably different according to kinds(particle size/stabilized ion) of colloidal silica(CS), kinds of silanes, content ratio of silane versus CS, and reaction degree in sol solution. We report the properties of sol-gel coating materials in which the factors of reaction are kinds of CS, contents ratio of CS and MTMS, and reaction time of sol. The contact angles of the coated films obtained from the mixed CS system showed a little good relationship with MTMS content increase to those from HSA CS reaction system and the change of contact angle didn't have much effect on reaction time of sol. In the coating films obtained from HSA CS reaction system, the surface was much rough in case of that the content MTMS decreased and the reaction of sol kept long. The surface roughness of films obtained from the mixed CS reaction system showed similar tendency, though its degree was a little different. In synthesis of sol-gel coating materials, we could identify that choice of CS kinds and content ratio of CS and silane were important and it was desirable the reaction time of sol is not long.

Fabrication of Thin Film Dielectric by Hybrid Sol (Hybrid Sol을 이용한 박막 유전체 제작)

  • Kim, Yong-Suk;Yoo, Won-Hee;Chang, Byeung-Gyu;Oh, Yong-Soo
    • Korean Journal of Materials Research
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    • v.17 no.4
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    • pp.185-191
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    • 2007
  • The purpose of this study is to evaluate the thin fihn dielectric made of hybrid sol, which consist of barium titanate powder, polymeric sol and other polymers. This sol will be used dielectric applied to small, thin electric passive components such as MLCC(Multi Layer Ceramic Condenser), resister, inductor. This sol is composed of mixed fine barium titanate powder and polymeric sol including Ba, Ti-precursor, solvent, chelating agent, chemical reaction catalyst, the additive sols to improve fired densification and temperature reliability. First at all, we mixed hybrid sol to be dispersed and be stabilized by ball milling for 24hrs. By spin coating method, we makes thin film dielectric on the convectional green sheet for MLCC. After heat treatments, we analyzes the structure morphology, physical, electrical properties and X5R Temperature properties.

Hydroxyapatite+TiO2 Composite Sol Coating on Cp-Ti (Cp-Ti 표면의 Hydroxyapatite+TiO2 복합 Sol 코팅에 관한 연구)

  • Kim, Yun-Jong;Kim, Taik-Nam;Lee, Sung-Ho
    • Korean Journal of Materials Research
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    • v.15 no.7
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    • pp.444-447
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    • 2005
  • In this study, $Hydroxyapatite+TiO_2(HAp+TiO_2)$ composite sol coatings on Cp-Ti substrates were deposited by using a sol-gel derived precursor. Prior to hydroxyapatite coating, the samples were micropolished and divided into three sets. The first set was coated with hydroxyapatite (HAp) directly on Cp-Ti. The second set was first coated with intermediate titania layer and then coated with HAp. The third set samples were coated with $HAp+TiO_2$ (50:50) composite sol. Each samples were predried at $200^{\circ}C$, and heat treated at $600^{\circ}C$. The formation of hydroxyapatite has been confirmed by XRD analyses and the substrate material was found to be oxidized with negligible amount of CaO in the coating. The NaOH treated samples showed the presence of rutile crystal. The SEM studies revealed surface morphologies of each samples. $HAp+TiO_2$ composite sol coating layer was found to be smooth. The bonding strength of each samples were calculated using pull out tests. The bonding strength of the $HAp+TiO_2$ composite sol coating on substrate was 29.35MPa.