• Title, Summary, Keyword: colloidal silica

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Mixed Nano Silica Colloidal Slurry for Reliability Improvement of Sapphire Wafer CMP Process (사파이어 웨이퍼 CMP 공정 신뢰성 향상을 위한 혼합 나노실리카 콜로이달 슬러리)

  • Chung, Chan Hong
    • Journal of Applied Reliability
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    • v.14 no.1
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    • pp.11-19
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    • 2014
  • A colloidal silica slurry has been manufactured by mixing nano silica powders having different grain size to improve the reliability of Sapphire wafer CMP process. The main reliability problem of CMP process such as the breaking of wafer can be prevented by reducing the size of particles in a slurry. While existing commercial colloidal silica slurries are usually made of single grain size silica powder of about 120nm, in the present study 40nm and 100nm silica powders are mixed to achieve a similar removal rate. The new colloidal silica slurry showed wafer removal rate of $3.04{\mu}m/120min$ while that of a commercial colloidal silica slurry was $3.03{\mu}m/120min$. The roughness was less than $4{\AA}$ and scratch was 0. It is also expected that the reduction of the size of nano silica particles can improve the dispersion stability and prolong the useful life of the slurry.

Effect of Colloidal Silica on Selective Catalytic Reduction (SCR) Catalyst Activity and Thermal Stability (Colloidal Silica의 특성이 SCR 촉매의 성능 및 열적 안정성에 미치는 영향)

  • Cha, Jin-Sun;Lee, Hyung Won;Shin, Min-Chul;Jeong, Bora;Kim, Hong-Dae
    • Applied Chemistry for Engineering
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    • v.31 no.1
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    • pp.61-66
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    • 2020
  • In this study, the effect of characteristics of colloidal silica, which was used as an additive in the compression/coating catalyst process, on activities and thermal stabilities of the catalysts was investigated. The shape, size, specific surface area and porosity, and composition of four different types of colloidal silica materials were analyzed, and the NOx conversion of V2O5/TiO2 catalyst prepared by these colloidal silica were studied. Properties of the catalysts prepared by colloidal silica depend on the nature of the colloidal silica used, in particular the alkaline substances such as Na in the silica were evaluated to be directly effect on the deNOx conversion of the catalyst. In addition, higher silica contents in the colloidal silica were found to improve the deNOx activity and thermal stability of the catalyst.

Effect of Colloidal Silica on the Photochromic Properties of Hard Coating Films Prepared by Sol-Gel Method (Colloidal Silica가 Sol-Gel 하드 코팅 막의 광 변색 특성에 미치는 영향)

  • Shin, Yong Tak;Lee, Min Ji;Cho, Kyung Sook;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.49 no.5
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    • pp.535-540
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    • 2011
  • Organic-inorganic hybrid coating solutions were prepared starting from colloidal silica, lanthanum nitrate and ${\gamma}$-glycidoxypropyl trimethoxysilane by the sol-gel method. Also, spiropyran-doped hard coating solutions were prepared by mixing the spiropyran solution, obtained after dissolving spiropyran dye into tetrahydrofuran solvent, with the organic-inorgnic hybrid coating solutions. The spiropyran-doped hard coating solutions were applied as a thin layer to polycarbonate sheets, and their photochromic properties were investigated. The effect of amount of colloidal silica added into the coating solutions was investigated on the photochromic properties of coating films. Both decoloration rate and pencil hardness of the coating films were increased with increasing the amounts of colloidal silica.

The Control of Anti-slip Characteristics of Packaging Paper Using Nano-colloidal Silica (나노 콜로이달 실리카를 이용한 포장용지의 미끄럼특성 제어)

  • Lee, Won-No;Kim, Hyoung-Jin
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.37 no.3
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    • pp.33-40
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    • 2005
  • In this study, a nano-colloidal silica sol was applied to control the anti-slip property by spraying on kraft paper. Two kinds of nano-colloidal silica sol which have cationic and anionic charge were applied in kraft paper, and the friction and physical strength properties of kraft paper were investigated. The application of colloidal silica sol on wet web in wet-end process by spraying method was tried to improve the friction property and to avoid the general problems of machine contaminations caused by the scattering of sprayed silica particles in dryer part. The physical properties of sheet were also improved by the application of wet web spraying method, and the optimum conditions of wet web spraying operation were closely related with the conditions of pH and electrical charge of wet web and silica sol.

Preparation of Silylated Waterborne Polyurethane/Silica Nanocomposites Using Colloidal Silica (Colloidal Silica를 이용한 Silylated Waterborne Polyurethane/Silica Nanocomposite의 제조)

  • Hong, Min Gi;Shin, Yong Tak;Choi, Jin Joo;Lee, Won Ki;Lee, Gyoung Bae;Yoo, Byung Won;Lee, Myung Goo;Song, Ki Chang
    • Korean Chemical Engineering Research
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    • v.48 no.5
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    • pp.561-567
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    • 2010
  • Silylated waterborne polyurethane was synthesized by capping the NCO groups of polyurethane prepolymer, prepared from isophrone diisocyanate, poly(tetramethylene glycol) and dimethylol propionic acid, with aminopropyl triethoxysilane. Subsequently, it was mixed with colloidal silica to prepare silylated waterborne polyurethane/silica nanocomposites. The average sizes of nanocomposite particles, measured by dynamic light scattering, showed almost the same value, irrespective of increasing silica content. However, the prepared nanocomposites showed better thermal stability than pure waterborne polyurethane.

Characteristics Evaluation of Thin Films Formed on Mg-Al Alloy in Various Chemical Conversion Solution Conditions (다양한 화성처리 용액 조건에서 마그네슘-알루미늄 합금위에 형성된 박막의 특성 평가)

  • Jang Seok-Ki;Kim Seong-Jong;Kim Jeong-Il
    • Journal of the Korean Society of Marine Engineering
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    • v.29 no.1
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    • pp.98-106
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    • 2005
  • The chemical conversion film formed on magnesium alloy was investigated by using the colloidal silica with some parameters such as solution pH. temperature, solution conditions, and treatment time. Moreover. the solutions consisted of colloidal silica titanium sulfate, and cobalt ions were used for the colloidal silica film to having a good corrosion resistance and adhesion properties. It was thought that the film at 298K was made with combination of Si-O. The quantity of film formed at high temperature such as 333K and 353K is smaller than dissolved quantity during chemical conversion treatment. Adding $CoSO_4$ to the colloidal silica solution enhanced the adhesion force between the silica film and magnesium substrate, The optimum conditions for the chemical conversion treatment solution were PH 2.90 s treatment, and 298K.

BAM:Mn Phosphor Prepared from Spray Solution with Colloidal Silica (실리카 함유 콜로이달 분무용액으로부터 합성된 BAM:Mn 형광체)

  • Ju, Seo-Hee;Koo, Hye-Young;Hong, Seung-Kwon;Kim, Do-Youp;Kang, Yun-Chan
    • Korean Journal of Materials Research
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    • v.16 no.2
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    • pp.123-128
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    • 2006
  • [ $BaMgAl_{10}O_{19}:Mn^{2+}$ ](BAM:Mn) phosphor particles with spherical shape were prepared by spray pyrolysis from colloidal solution with silica. The phosphor particles prepared by spray pyrolysis from aqueous solution had irregular morphology after high temperature post-treatment. On the other hand, the phosphor particles prepared from spray solution with colloidal silica had spherical shape after post-treatment. Colloidal silica used as additive improved the spherical shape and filled morphology of the precursor particles prepared by spray pyrolysis. The precursor particles with filled structure produced the BAM:Mn phosphor particles with spherical shape and non-aggregation characteristics after post-treatment at $1400^{\circ}C$ under reducing atmosphere. The phosphor particles prepared from colloidal solutions formed the crystal structure of BAM:Mn phosphor irrespective of the silica contents. The BAM:Mn phosphor particles prepared from aqueous and colloidal solutions had similar photoluminescence intensities under vacuum ultraviolet.

Polishing of Oxide film by colloidal silica coated with nano ceria (나노 세리아 입자가 표면 코팅된 콜로이달 실리카 슬러리의 Oxide film 연마특성)

  • Kim, Hwan-Chul;Lee, Seung-Ho;Kim, Dae-Sung;Lim, Hyung-Mi
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.35-37
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    • 2005
  • 100, 200nm 크기의 colloidal silica 각각에 나노 ceria 입자를 수열합성법으로 코팅하였다. Colloidal silica 입자에 ceria를 코팅 시 slurry의 pH조절과 수열처리에 이용하여 silica에 ceria가 코팅됨을 TEM과 zeta-potential을 이용하여 확인하였다. 연마 슬러리의 분산 안정성과 연마효율을 높이기 위하여 슬러리의 pH 는 9로 하였으며, 이때의 zeta-potential 값은 -25 mV이었다. 1 wt%로 제조된 연마슬러리를 이용하여, 4 inch $SiO_2$, $Si_3N_4$ wafer를 압력변화에 따른 연마특성을 관찰 하였다. Ceria coated colloidal silica 100 nm, 200 nm와 commercial한 $CeO_2$입자를 연마압력 6 psi로 oxide film을 연마한 결과 연마율이 각각 2490 ${\AA}/min$, 4200 ${\AA}/min$, 4300 ${\AA}/min$으로 측정되었다. 또한 $SiO_2$, $Si_3N_4$ film의 6 psi압력에서 ceria coated colloidal silica 100 nm, 200 nm와 commercial 한 $CeO_2$입자의 선택비는 3, 3.8, 6.7 이었다. 입자크기가 클수록 연마율이 높으며, Preston equation을 따라 연마 압력과 연마율이 비례하였다.

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Preparation and Interface Properties of Colloidal Silica (콜로이드 실리카의 제조 및 계면특성)

  • Lee, Han Chul;Kim, Jong Hyub;Chang, Yoon Ho
    • Applied Chemistry for Engineering
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    • v.17 no.4
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    • pp.386-390
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    • 2006
  • Colloidal silica which has high surface area and excellent surface properties are chemically stable inorganic materials and used for various applications in industry. Silica sol was prepared from sodium silicate solution by acid neutralization method and ion exchange treatment to remove sodium ions. Through the experimental analysis for controlling factors of particle growth rate, such as temperature, pH, and aging time, the uniform size distribution of silica sol could be obtained. The size distribution and shape of silica sol was measured by TEM and dynamic light scattering method. Zeta potential change and gelling phenomena of silica sol and its rheological properties also investigated.