• Title/Summary/Keyword: hollow microsphere

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Fabrication of Porous Alumina Ceramics Using Hollow Microspheres as the Pore-forming Agent

  • Nie, Zhengwei;Lin, Yuyi
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.24 no.4
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    • pp.368-373
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    • 2015
  • Porous alumina ceramics with two different pore sizes were fabricated using hollow microspheres as the pore-forming agent. The relative density, total porosity, and microstructure of the obtained alumina ceramics were studied. It was found that the total porosity of sintered samples with different amounts of hollow microsphere content, from 2.0 to 4.0 wt%, was 69.3-75.6%. The interconnected and spherical cell morphology was obtained with 3.0 wt% hollow microsphere content. The resulting ceramics consist of a hierarchical structure with large-sized cells, and small-sized pores in the cell walls. Moreover, the compressive strength of the sintered samples varied from 8.3-11.5 MPa, corresponding to hollow microsphere contents of 2.0-4.0 wt%.

Investigation on the Pore Properties of the Microcellular ZrO2 Ceramics Using Hollow Microsphere (중공형 미세구를 이용한 마이크로셀룰라 지르코니아의 가공 특성 고찰)

  • Lee, Eun-Jung;Song, In-Hyuek;Kim, Hai-Doo;Kim, Young-Wook;Bae, Ji-Soo
    • Journal of the Korean Ceramic Society
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    • v.46 no.1
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    • pp.108-115
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    • 2009
  • In this study, a novel-processing route for producing microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellular zirconia ceramics involves hollow microsphere as a pore former which has extremely low density of $0.025\;g/cm^3$. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and compressive strength were investigated in the processing of microcellular zirconia ceramics. By controlling the content of hollow microsphere, it was possible to make the porous zirconia ceramics with porosities ranging from 45% to 75%. Typical compressive strength value of microcellular zirconia ceramics with ${\sim}65%$ porosity was over 50 MPa. By adjusting the mixing ratio of large and small zirconia powders, it was possible to control the pore structure from close to open pores.

Lightweight Porcelain using GHM(Glass Hollow Microsphere) (유리질 중공체 GHM(Glass Hollow Microsphere)을 활용한 자기의 경량화)

  • Kim, Geun-Hee;Choi, Hyo-Sung;Pee, Jae-Hwan;Cho, Woo-Seok;Kim, Kyeong-Ja
    • Journal of the Korean Ceramic Society
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    • v.48 no.1
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    • pp.74-79
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    • 2011
  • The pore generation technology using GHM (Glass Hollow Microsphere) was studied in order to reduce the weights of porcelain. In this study, we verify the property of modified slurry by adding GHM. The modified slurry was prepared by adding 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37) of GHM to the slurry for porcelain. The slurry viscosity were stable inside a content range of 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37). However, the viscosity of modified slurry increased more than 3.0 wt%(K1) and 6.5 wt%(K37). The formed specimen by slip casting was fired at $1229^{\circ}C$, $1254^{\circ}C$. As the amount of GHM content increased, the weight decreased and the addition of 1.0~2.5 wt%(K1), 1.0~6.0 wt%(K37) of GHM resulted in a weight drop of 30%(K1) and 25(K37). However, when the GHM content increased, the strength decreases over 70%. This is caused by the presence of a large volume of surface defects (pores) and defects from the agglomeration of GHM.

Effect of Pore Formers and Sintering Temperatures on Microstructure and Bending Strength of the Porous Zirconia Ceramics (기공 형성제 조절과 소결 온도의 변화가 다공질 지르코니아 세라믹스의 미세구조 및 강도에 미치는 영향)

  • Lee, Eun-Jung;Song, In-Hyuck;Ha, Jang-Hoon;Hahn, Yoo-Dong;Kim, Yang-Do
    • Journal of Powder Materials
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    • v.18 no.6
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    • pp.502-509
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    • 2011
  • In this study, a novel-processing route for fabricating microcellular zirconia ceramics has been developed. The proposed strategy for making the microcellula zirconia ceramics involved hollow microspheres as pore former. Compared to conventional dense microspheres pore former, well-defined pore structured zirconia ceramics were successfully fabricated. Effects of hollow microsphere content and sintering temperature on microstructure, porosity, pore distribution, and strength were investigated in the processing of microcellular zirconia ceramics.

Synthesis of TiO2 Hollow Microspheres Using Ionic Liquids (이온성액체를 이용한 이산화티타늄 미세중공체 합성)

  • Hong, Kiwon;Yoo, Kyesang
    • Applied Chemistry for Engineering
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    • v.22 no.3
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    • pp.340-342
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    • 2011
  • $TiO_2$ hollow microsphere was simply synthesized using various ionic liquids. Shapes and sizes of hollow microspheres were significantly different with the composition of ionic liquids. This is mainly attributed to the interaction between the organic solvent and the ionic liquid at the interface leading to the formation of micropsphere. Among the ionic liquids, 1-butyl-3-methylimidazolium tetrafluoroborate was the most effective to synthesize the hollow microsphere.

Effect of the Surfactant Concentration on the Formation of Water Glass-based Porous Hollow Silica Microsphere (Porous한 물유리 기반 실리카 중공 미세구 형성에 대한 계면활성제 농도의 영향)

  • Lee, Jihun;Kim, Younghun;Kim, Taehee;Park, Hyung-Ho
    • Journal of the Microelectronics and Packaging Society
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    • v.28 no.4
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    • pp.79-83
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    • 2021
  • In this study, hollow silica microspheres (HSM) of various sizes formed according to the concentration of surfactants using water glass as a precursor, which is advantageous for commercialization due to its lower unit cost compared to conventional silicon alkoxide (tetraethyl orthosilicate, TEOS) was synthesized. The physical properties of the silica hollow microspheres according to the concentration of surfactant were analyzed using Fourier transform infrared, contact angle measurement, Brunauer-Emmett-Teller and Barrett-Joyner-Halenda analyzers and field emission scanning electron microscopy. When porous water glass-based hollow silica spheres were prepared by adding a surfactant at an appropriate concentration, it was confirmed that excellent hollow silica spheres were formed with a specific surface area of 169 m2/g, an average particle size of 25.3 ㎛, and a standard deviation of 6.25.

Lightweight Characteristics and Sintering behavior of Porcelain by Addition FAHM(Fly-Ash Hollow Microsphere) (FAHM(Fly-Ash Hollow Microsphere)첨가에 의한 도자기의 소성특성과 경량화)

  • Kim, Geun-Hee;Pee, Jae-Hwan;Kim, Jong-Young;Cho, Woo-Seok;Kim, Kyeong-Ja
    • Journal of the Korean Ceramic Society
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    • v.48 no.3
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    • pp.228-235
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    • 2011
  • Sintering behavior and lightweight characteristics of porcelain by addition of FAHM (Fly-Ash Hollow Microsphere) were evaluated. Green body of Backja composition (general porcelain) in which FAHM was added(15 and 20 wt%) was made by slip casting method. The green body was sintered at 1270 and $1290^{\circ}C$ and maintained for 1h. The bulk density and linear shrinkage of the sintered body with FAHM (20 wt%) decreased. As the contents of FAHM. increased, mullite and cristobalite phases increased. In the microstructure, FAHM shells remained after sintering, and the generation of mullite fibers around FAHM shells also were confirmed. the weight of porcelain with of 20% FAHM decreased by 40% and residual FAHM shells promoted the mullite of generation in the matrix.

A Study on the Preparation of MnO2 Hollow Microspheres (MnO2 중공 미세구의 제조에 관한 연구)

  • Moon, Jin Hee;Park, Yong Sung
    • Applied Chemistry for Engineering
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    • v.17 no.6
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    • pp.648-652
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    • 2006
  • Demand for $MnO_{2}$ has been increased with interest for its various applications in the fields of battery, catalyst, and capacitor. In this study, $MnO_{2}$ hollow microspheres were synthesized by sacrificial core method. $MnO_{2}$ nano particles were produced by the hydrolysis and condensation of manganese acetate. The stable $MnO_{2}$ hollow microspheres can very well be synthesized with mixing 0.2% of water, 0.65 mM of manganese acetate, and 0.02 mM catalyst at a room temperature.

A Study on the Preparation of PBAST/PVA Double Layered Hollow Microspheres (PBAST/PVA 이중층 중공미세구의 제조에 관한 연구)

  • Song, Myung-Sook;Woo, Je-Wan
    • Clean Technology
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    • v.14 no.4
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    • pp.256-264
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    • 2008
  • In this study, using PBAST (poly(butylene adipate-co-succinate-co-terephthalate)) which was eco-friendly biodegradable aliphatic polyester, PBAST/PVA (poly(vinyl alcohol)) double-layered hollow microspheres were prepared with the water/oil/water multiple emulsion ($W_1/O/W_2$) method. The double-layered hollow microspheres were manufactured with the yield of 30.92% when the concentration of polymer PBAST in organic phase was 5 wt%, the concentration of PVA in inner aqueous phase was 5 wt%, the volume ratio of $W_1/O$ emulsion to outer aqueous phase was 1:4.5, and when co-surfactants that had large gap in HLB (hydrophile-lipophile balance) value were used. The bulk density of prepared hollow microsphere was 0.180 g/ml and particle size was $1.5{\sim}3\;{\mu}m$.

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