• 한국세라믹학회지
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• 제44권2호
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• pp.98-102
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• 2007

The stability of slurry and removal rate during recycling of colloidal silica slurry was evaluated in silicon wafer polishing. The particle size distribution, pH, and zeta potential were measured to investigate the stability of colloidal silica. Large particles appeared as recycling time increased while average size of slurry did not change. Large particles were identified by EDS(energy dispersive spectrometer) as foreign substances from pad or abraded silicon flakes during polishing. As the recycling time increased, pH of slurry decreased and removal rate of silicon reduced but zeta potential decreased inversely. Hence, it could be mentioned that decrease of removal rate is related to consumption of $OH^-$ ions during recycling. Attention should be given to the control of pH of slurry during polishing.

• 한국전기전자재료학회논문지
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• 제32권6호
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• pp.483-489
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• 2019

For machine learning techniques, a large amount of high-quality material property data should be accumulated. In this study, several data for an alumina tape casting process were produced with the variables of slurry viscosity, gap size, and coating speed. The alumina tapes were manufactured in the range of 1,000~6,000 cps for slurry viscosity, $300{\sim}1,000{\mu}m$ for gap size, and 0.5~2.0 m/min for coating speed. As a result, the lower the viscosity, coating speed, and gap size, the more pore-free tapes could be manufactured. The viscosity of the slurry limited the minimum thickness of the tape. Green sheets with high packing density were manufactured from the slurry of 100~6,000 cps slurry viscosity, coating speed of 0.5 m/min, and a $300{\sim}500{\mu}m$ gap size.

• 한국세라믹학회지
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• 제39권11호
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• pp.1042-1047
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• 2002

$Al_2O_3-SiO_2$계 세라믹 화이버를 주원료로 하는 세라믹섬유지를 제조하기 위하여 스러리 점도변화에 따른 세라믹화이버의 침강특성과 pH 변화에 따른 제타전위의 변화와 세라믹화이버 분산특성과의 관계를 분석하였다. 슬러리에서 세라믹화이버의 해섬 및 분산을 위한 슬러리 적정 점도는 28~31 cps이었고, pH 변화에 따라 제타전위는 민감하게 변화하여 pH 7.5~9.5에서 -35~-36 mV로 최대치를 나타내었으며, 이때 세라믹화이버의 침강량도 가장 적게 나타나 슬러리의 제타전위가 증가함에 따라 세라믹화이버의 분산도 잘 이루어짐을 알 수 있었다. 습식초지공정 중 흡입탈수는 함수율 83 wt% 이상으로 유지시켜야 바인더 손실을 막을 수 있었으며, 압축탈수 후 함수율이 62wt% 미만이 되어야 습식회수가 가능하였다. 제조된 세라믹섬유지는 인장강도 $102 kgf/cm^2$, 평량 $98 g/m^2$를 나타내었다.

• 한국세라믹학회지
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• 제36권6호
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• pp.625-631
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• 1999

Ceramic tapes were fabricated by ultrasonically spraying slurries of monodispersed spherical and alumina powders. Effects of slurry compositions on tape forming were investigated. A relatively fast rate of solvent evaporation caused pores and cracks to be formed. A good chemical affinity between solvent and binder gave rise to binder separation resulting in inhomogeneous distribution of binder. Defect-free silica tapes with uniform distribution of particle packing and the binder were obtained from the solvent having a low chemical affinity and a slow evaporation rate and containing appropriate amounts of the binder and the plasticizer. Tape thickness could be controlled by adjusting solids loadings and slurry feed rates. It was possible to fabricate a tape in 15 $\mu\textrm{m}$ thickness from 7 vol% alumina slurry.

• 한국전기전자재료학회논문지
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• 제21권3호
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• pp.236-241
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• 2008

The effect of organic solvent mixture ratio on the rheology property of slurry and thickness control of ceramic green sheet was investigated. For selecting a suitable dispersant multiple light scattering method was used to evaluate the particle migration velocity and variation of clarification layer thickness. Using the selected dispersant the dispersion property of solution according to solvent mixture ratio was investigated. Binder and plasticizers were added to formulate slurries and their viscosity was evaluated according to solvent mixture ratio. Ceramic green sheets with average thickness of 30, 50 urn were fabricated via tape casting and their thickness tolerances measured. As a result according to solvent mixture ratio the solution and slurry properties varied and for the mixture ratio of ethanol/toluene of 80/20 the ceramic green sheet with the lowest thickness tolerance was obtained.

• 한국세라믹학회지
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• 제48권2호
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• pp.189-194
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• 2011

Metallurgical grade silicon was recovered from slurry waste for ingot sawing process by acid leaching and thermal treatment. SiC abrasive was removed by gravity concentration and centrifugation. Metal impurities were removed by the acid leaching using HF/HCl. The remaining SiC was separated by the thermal treatment at $1600^{\circ}C$ in an inert atmosphere by the difference in melting points. The purity of the obtained silicon was found to be around 99.7%.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.898-901
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• 2006

To fabricate mono layer green sheet (MLGS) of transparent dielectric for PDP front panel, dispersion of transparent dielectric slurry and various properties of green sheets were examined as a function of amount and kinds of organic additives. Sedimentation height and viscosity of slurry were measured to determine proper types and amount of dispersant in non-aqueous system transparent dielectric slurry. Many MLGS having various ratios of the transparent dielectric glass frit, binder and plasticizer were fabricated. Finally we got the transparent dielectric layer of high transparency and free from residual pore might be remained in the gap between the electrodes.

• The Korean Journal of Ceramics
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• 제5권2호
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• pp.104-109
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• 1999

Rheological properties of dense slurries over 45 volume % with different monosaccharides and disaccharides were checked in order to increase the solid content of dense slurries without sacrificing plasticity using creep testing method. Strain in creep test showed good correlations with Burger model which is expressed as an exponential function of time. Among several monosaccharides and disaccharides studied here, fructose and sucrose were most effective in making dense alumina slurry plastic than other monosaccharides and disaccharides like glucose, galactose, xyloss and maltose. In the case of dense alumina slurry with sucrose, sucrose content or additional water content enhanced to the plasticity of the slurries.

• 한국세라믹학회지
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• 제56권5호
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• pp.468-473
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• 2019

This study focused on manufacturing an inorganic insulation material set with various amounts of calcium-sulfoaluminate (CSA) (hauyne) content for enhancing both workability (demolding, handling) and the high thermal insulating property. To carry out the experiment, the amounts of CSA utilized were 5%, 10%, 15%, and 20%, with anhydrous gypsum added in equal proportion to produce a stable formation. As the content of CSA increased, a sinking phenomenon occurred because of the hydration reaction from the slurry, so it was difficult to utilize a retarder normally used in the cement manufacturing process. However, an RCOOM surfactant was able to solve the local clumping problem from cement and CSA and obtain a rapid retarding effect, so it was included in this process at 0.3%. Furthermore, the cement fineness was not 7000 ㎠/g but rather 3300 ~ 4000 ㎠/g to prevent a rapid temperature increase in the slurry. The specific gravity of the sample manufactured with 20% CSA was approximately 0.11 g/㎤, and its thermal conductivity was 0.041 W/m·K, providing an excellent insulating property.

• Journal of Ceramic Processing Research
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• 제19권5호
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• pp.407-412
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• 2018

In this study, we have made a cement based inorganic insulation material and added CSA (Hauyne Clinker) to reduce the demolding time and enhance the handling workability. CSA contents were varied by 0%, 1%, 3%, 5% and the atmospheric steam curing was tried for enhancing the compressive strength. As the CSA contents are increased to 5%, a rapid reaction of hydration caused the sinking of the slurry. So, the setting-retarder was added to control the reaction of hydration. By this, the sinking of the slurry was controlled but the height of the green body after expansions was a little bit lowered. In the CSA-added slurry, it was possible to demold within 24 hours and in case of CSA 5%-added, the sufficient workability was secured. Atmospheric steam curing (temperatures $-40{\sim}80^{\circ}C$, for 6~10 hrs.) was attempted to improve the compressive strength and found that an excellent strength of 0.25 MPa was achieved at $80^{\circ}C$ for 8 hrs. Specific gravity was about $0.12{\sim}0.13g/cm^3$ and heat conductivity was about 0.045 W/mK in all specimens. This strategy significantly improves the compressive strength of CSA 5%-added specimen up to 25% compared to without CSA added specimen.