• Title/Summary/Keyword: Silica particle

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액상계면반응에 의한 실라카 중공 다공성 미소구의 제조 및 표면개질에 의한 특성

  • 정원범;고종성
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.13 no.1
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    • pp.15-28
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    • 1987
  • Silica spheres were prepared by interfacial reaction method. Factors in-fluencing to the mean particle size and specific surface area of silica spheres were investigated. The experiment about the surface modification of silica spheres was carried out. It was observed that silica spheres have characteristics of the spherical shape with the vacancy in the inner side, high surface area, and reaction tendency by many silanol group. The mean particle size of silica spheres is dependent on the surfactant concentration and W/O ratio. The specific surface area is influenced by SiO2/Na2O mole ratio in sodium silicate. Silica spheres coated with titanium dioxide or zirconium dioxide improve the UV protection effect. Titanate and silane coupling agent make chemical bond with silica surface and improve the organophile and the dispersibility of silica spheres.

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Size, Shape, and Crystal Structure of Silica Particles Generated as By-products in the Semiconductor Workplace (반도체 작업환경 내 부산물로 생성되는 실리카 입자의 크기, 형상 및 결정 구조)

  • Choi, Kwang-Min;Yeo, Jin-Hee;Jung, Myung-Koo;Kim, Kwan-Sick;Cho, Soo-Hun
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.25 no.1
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    • pp.36-44
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    • 2015
  • Objectives: This study aimed to elucidate the physicochemical properties of silica powder and airborne particles as by-products generated from fabrication processes to reduce unknown risk factors in the semiconductor manufacturing work environment. Materials and Methods: Sampling was conducted at 200 mm and 300 mm semiconductor wafer fabrication facilities. Thirty-two powder and airborne by-product samples, diffusion(10), chemical vapor deposition(10), chemical mechanical polishing(5), clean(5), etch process(2), were collected from inner chamber parts from process and 1st scrubber equipment during maintenance and process operation. The chemical composition, size, shape, and crystal structure of silica by-product particles were determined by using scanning electron microscopy and transmission electron microscopy techniques equipped with energy dispersive spectroscopy, and x-ray diffractometry. Results: All powder and airborne particle samples were composed of oxygen(O) and silicon(Si), which means silica particle. The by-product particles were nearly spherical $SiO_2$ and the particle size ranged 25 nm to $50{\mu}m$, and most of the particles were usually agglomerated within a particle size range from approximately 25 nm to 500 nm. In addition, the crystal structure of the silica powder particles was found to be an amorphous silica. Conclusions: The silica by-product particles generated from the semiconductor manufacturing processes are amorphous $SiO_2$, which is considered a less toxic form. These results should provide useful information for alternative strategies to improve the work environment and workers' health.

Wear Behavior of Silica filled Styrene-Butadiene Rubber: A Comparative Study Between the Blade-Type and Akron-Type Abrader

  • Gi-Bbeum Lee;Dongwon Kim;Seowon Lee;Seonhong Kim;Myung-Su Ahn;Bismark Mensah;Changwoon Nah
    • Elastomers and Composites
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    • v.58 no.4
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    • pp.179-190
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    • 2023
  • The effect of the particle size and silica structure on the wear behavior of Silica/Styrene-Butadiene Rubber (SBR) compounds was investigated using a blade-type abrader and the findings were compared with those obtained with an Akron abrader. The compensated characteristic parameter (Ψc), which was the contributory factor of the combined effect of the particle size and filler structure, was introduced. This parameter was found to exhibit a linear relationship with the Young's modulus. The Young's modulus correlated more with Ψc than the uncompensated characteristic parameter (Ψ) modeled for carbon black. The wear rate and volume loss measured using a blade-type abrader and Akron abrader were respectively observed to be inversely proportional to Ψc, that is, the wear resistance of Silica/SBR compound improved as the particle size became smaller and the silica structure became intricate. The coefficient of determination (R2) obtained from the linear relationship between Ψc and wear rate was higher than those between Ψc and volume loss for the Silica/SBR compound. Thus, the blade-type abrader exhibited high potential to be used for accurately evaluating the effect of particle size and structural properties of silica on the wear behavior of SBR compounds.

Double Convective Assembly Coatings of FePt Nanoparticles to Prevent Particle Coalescence during Annealing

  • Hwang, Yeon
    • Korean Journal of Materials Research
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    • v.21 no.3
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    • pp.156-160
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    • 2011
  • FePt nanoparticles suspension was synthesized by reduction of platinum acetylacetonate and decomposition of iron pentacarbonyl in the presence of oleic acid and oleyl amine. FePt nanoparticles were coated on a substrate by convective assembly from the suspension. To prevent the coalescence during the annealing of FePt nanoparticles double convective coatings were tried. First convective coating was for silica particle assembly on a silicon substrate and second one was for FePt nanoparticles on the previously coated silica layers. It was observed by scanning electron microscopy (SEM) that FePt nanoparticles were dispersed on the silica particle surface. After annealing at $700^{\circ}C$ for 30 minutes under nitrogen atmosphere, FePt nanoparticles on silica particles were maintained in a dispersed state with slight increase of particle size. On the contrary, FePt nanoparticles that were directly coated on silicon substrate showed severe particle growth after annealing due to the close-packing of nanoparticles during assembly. The size variation during annealing was also verified by X-ray diffractometer (XRD). It was suggested that pre-coating, which offered solvent flux oppose to the capillary force between FePt nanoparticles, was an effective method to prevent coalescence of nano-sized particles under high temperature annealing.

An Experimental Study of Silica Particle Growth in a Coflow Diffusion Flame Utilizing Light Scattering and Local Sampling Technique (I) - Effects of Flame Temperature - (광산란과 입자포집을 이용한 동축류 확산화염 내의 실리카 입자의 성장 측정(I) - 화염온도의 영향 -)

  • Cho, Jaegeol;Lee, Jeonghoon;Kim, Hyun Woo;Choi, Mansoo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.9
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    • pp.1139-1150
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    • 1999
  • The evolution of silica aggregate particles in coflow diffusion flames has been studied experimentally using light scattering and thermophoretic sampling techniques. The measurements of scattering cross section from $90^{\circ}$ light scattering have been utilized to calculate the aggregate number density and volume fraction using with combination of measuring the particle size and morphology through the localized sampling and a TEM image analysis. Aggregate or particle number densities and volume fractions were calculated using Rayleigh-Debye-Gans and Mie theory for fractal aggregates and spherical particles, respectively. Of particular interests are the effects of flame temperature on the evolution of silica aggregate particles. As the flow rate of $H_2$ increases, the primary particle diameters of silica aggregates have been first decreased, but, further increase of $H_2$ flow rate causes the diameter of primary particles to increase and for sufficiently larger flow rates, the fractal aggregates finally become spherical particles. The variation of primary particle size along the upward jet centerline and the effect of burner configuration have also been studied.

The Adhesion of Abrasive Particle during Poly-Si, TEOS and SiN CMP (Poly-Si, TEOS, SiN 막질의 CMP 공정 중의 연마입자 오염 특성 평가.)

  • Kim, Jin-Young;Hong, Yi-Kwan;Park, Jin-Goo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.561-562
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    • 2006
  • The purpose of this study was to investigate the root cause of adhesion of silica and ceria particles during Poly-Si, TEOS, and SiN CMP process, respectively. The zeta-potentials of abrasive particles and wafers were observed negative surface charges in the alkaline solutions. SAC and STI patterned wafers have intermediate values of their composition surface's zeta potentials. The theoretical interaction force and adhesion force of silica and ceria particle were calculated in solution with acidic, neutral and alkaline pH. A stronger attractive force was calculated for silica and ceria particles on wafers in acidic solutions than in alkaline solutions. The theoretical interaction forces of the SAC and STI patterned wafers have intermediate values of their constitution wafer's values. The adhesion forces is observed lower values in alkaline solutions than in acidic solutions. And the ceria particle has lower adhesion than that of the silica particle.

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Synthesis of Vinyl-nano Silica Ball Composite : Its Application to Clearcoat (비닐-나노실리카볼 화합물의 클리어코트 특성 연구)

  • Kim, Bong-Gyeom;Park, Gun-Hee;Lee, Yong-Hwa;Noh, Seung-Man;Lee, Jae-Woo;Park, Seung-Kyu
    • Applied Chemistry for Engineering
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    • v.21 no.6
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    • pp.670-675
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    • 2010
  • Inorganic-organic hybrid material such as vinyl-nano sized silica ball was synthesized by acrylo-alkoxysilane and nano silica ball with different particle size. And then they were formulated into acrylic-melamine clearcoat. This material is fully characterized with various analytical methods and applied for strength measurement. The glossy effect, matting effect and anti-scratching properties of materials were investigated for further growth and maintenance. When the particle size of nano silica ball is 20~30 nm, the glossy retain effect was increased by 7% compared to bare acrylic-melamine clearcoat. When a commercially available silica Aerosil 200 (Hydrophilic fumed silica, average particle size 12 nm, Degussa) react with vinyl alkoxysilane vinyl-fumed silica complex form. The vinyl-fumed silica along with clearcoat increases only 2% increase at glossy retain. Nano-scratch test results also support the glossy retain effect of vinyl nano-sized silica ball in clearcoat.

A Study on Evaluation for Sampling and Analytical Methods of Diatomaceous Earth Dust (규조토 분진 측정 및 분석 방법의 비교에 관한 연구)

  • Lim, Hyun Sul;Kim, Ji Yong;Cheong, Hoe Kyeong
    • Journal of Korean Society of Occupational and Environmental Hygiene
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    • v.5 no.2
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    • pp.212-225
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    • 1995
  • This study was performed in a diatomite factory located at Pohang City, Kyeongsangbuk-Do. The major objectives were to evaluate sampling and analytical methods of diatomaceous earth dust. Concentrations of total and respirable diatomaceous earth dust were measured. Size distribution of dust was analyzed by a personal cascade impactor and the particle size analyzer which is an application of multiple diffraction method. Also crystalline silica in respirable and total dust samples was analyzed quantitatively by X-ray diffraction and Fourie Transform Infrared Spectroscopy(FTIR). The results were as follows: The airborne total and respirable dust concentrations, particle size distribution, and cristalline silica(quartz) concentrations showed approximately a log-normal distribution. The means of totaldust concentrations at flour maufacturing, fire brick grinding and packaging processes exceeded the Korean and American Conference of Governmental Industrial Hygienists standards, $10mg/m^3$. The size distribution of diatomaceous earth dust was log-normal and identified as the rspirable particle mass and thoracic particle mass. The crystalline silica in respirable and total dust samples was identified to quartz and contained about 10 % in those samples. Finally, it is necessary to study the applicability of multiple diffraction for particle size distribution to compare the ACGIH's size selective sampling with other materials containing crystalline silica. Also, advanced quantitative study to X-ray diffraction and FTIR methods shoud be carried out 10 verify general and specific characteristics for respirable crystalline silica.

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Wear characteristics on particle volume fraction of nano silica composite materials (입자 함유율의 변화에 따른 나노 실리카 복합재료의 마모 특성)

  • Lee, Jung-Kyu;Koh, Sung Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.49 no.4
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    • pp.492-499
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    • 2013
  • The characteristics of abrasive wear of the rubber matrix composites filled with nano sized silica particles were investigated at ambient temperature by pin-on-disc friction test. The range of volume fraction of silica particles tested are between 11% to 25%. The cumulative wear volume and friction coefficient of these materials on particle volume fraction were determined experimentally. The major failure mechanisms were lapping layers, deformation of matrix, ploughing, deboding of particles and microcracking by scanning electric microscopy photograph of the tested surface. The cumulative wear volume showed a tendency to increase nonlinear with increase of sliding distance. As increasing the silica particles of these composites indicated higher friction coefficient.

Impact fracture behavior on particle volume fraction of nano silica composite materials (입자 함유율의 변화에 따른 나노 실리카 복합재료의 충격파괴거동)

  • LEE, Jung-Kyu;KOH, Sung Wi
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.51 no.3
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    • pp.454-460
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    • 2015
  • The present study is undertaken to evaluate the effect of volume fraction on the results of Charpy impact test for the rubber matrix filled with nano sized silica particles composites. The Charpy impact tests are conducted in the temperature range $0^{\circ}C$ and $-10^{\circ}C$. The range of volume fraction of silica particles tested are between 11% to 25%. The critical energy release rate $G_{IC}$ of the rubber matrix composites filled with nano sized silica particles is affected by silica volume fraction and it is shown that the value of $G_{IC}$ decreases as volume fraction increases. In regions close to the initial crack tip, fracture processes such as matrix deformation, silica particle debonding and delamination, and/or pull out between particles and matrix which is ascertained by SEM photographs of Charpy impact fracture surfaces.