• Title/Summary/Keyword: Ceramic dispersant

Search Result 68, Processing Time 0.028 seconds

Preparation of Fe2O3 Coated on Mica for Infrared Reflectance Red Pigment and Thermal Property of Its Isolation-Heat Paint (Fe2O3가 코팅된 판상 mica의 적외선 반사용 적색안료 제조 및 차열도료의 열특성)

  • Lee, Hyun Jin;Kim, Dae Sung;Lee, Seung-Ho;Lim, Hyung Mi;Choi, Byung-Ki;Kang, Kwang-Jung;Jeong, Jae Il;Cho, Kum-Sung
    • Korean Journal of Materials Research
    • /
    • v.25 no.2
    • /
    • pp.61-67
    • /
    • 2015
  • $Fe_2O_3$ coated plate mica($Fe_2O_3$/mica) for infrared reflectance red pigment was prepared under hydrothermal treatment. $Fe_2O_3$ was perfectly coated on mica via the difference of surface charge between $Fe_2O_3$ and mica particles at pH 3. $Fe_2O_3$/mica was then calcined at $800^{\circ}C$ to stabilize the coated layer on mica. The infrared(IR) reflectance pigments were characterized by X-ray diffraction, FE-SEM, zeta potential, and a UV-Vis-NIR spectrophotometer. In particular, the CIE color coordinate and IR reflectance properties of $Fe_2O_3$/mica pigments were investigated in relation to the thickness variation of the $Fe_2O_3$ layer coated on mica of various lateral sizes. The isolation-heat red paints containing the pigments were prepared and optimized with a thinner, settling agent, and dispersant. Then, the films were made. The thermal property of isolation-heat on these films was observed through the relationship of the IR reflectance value, which was based on the variation of the $Fe_2O_3$ layer's thickness coated on mica and mica's lateral size as IR reflectance pigment. With an increase in IR reflectance on these films, the thermal property of isolation-heat was effectively enhanced.

A Study on the Optimization of α-Al2O3 Powder Manufacturing for the Application of Separators for Lithium-Ion Secondary Batteries (리튬이차전지용 분리막 적용을 위한 α-알루미나 분말 제조 최적화 연구)

  • Dong-Myeong Moon;Da-Eun Hyun;Ji-Hui Oh;Jwa-Bin Jeon;Yong-Nam Kim;Kyoung-Hoon Jeong;Jong-Kun Lee;Sang-Mo Koo;Dong-Won Lee;Jong-Min Oh
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.36 no.6
    • /
    • pp.638-646
    • /
    • 2023
  • Recently, active research has been conducted to enhance the power characteristics and thermal stability of lithium-ion batteries (LiBs) by modifying separators using a ceramic coating method. However, since the thermal properties and surface features of the separator vary depending on the characteristics of the ceramic powders applied to the separator, it is crucial to manufacture ceramic powders optimized for the separator's performance. In this study, we evaluated the characteristics of three types of α-alumina (A-1, A-2, and A-3) produced with varying dispersant contents and milling times, in addition to commercial α-alumina (AES-11). Subsequently, the optimized powders (A-3) were coated onto the separator using an aqueous binder for comparison with the characteristics of an AES-11 coated separator and an uncoated PE separator. The A-3 coated separator improved electrolyte wettability with a low contact angle (44.69°) and increased puncture strength (538 gf). Furthermore, it exhibited excellent thermal stability, with a shrinkage value of 5.64% when exposed to 140℃ for 1 hour, compared to the AES11 coated separator (6.09%) and the bare PE separator (69.64%).

Hydrogenation of Methyl Dodecanoate Using Copper Chromite (분산액에서의 Copper Chromite 합성 및 Methyl Dodecanoate의 수소화반응)

  • Kang, Ho-Cheol;Lee, Sang-Hoon;Park, Jong-Mok;Kim, Dong-Pyo;Lee, Byung Min
    • Applied Chemistry for Engineering
    • /
    • v.20 no.2
    • /
    • pp.201-207
    • /
    • 2009
  • The hydrogenation reaction of methyl dodecanoate for the synthesis of 1-dodecanol has been carried out in the presence of a copper chromite catalyst. The catalysts were synthesized by ceramic method, co-precipitation, and improved co-precipitation method and the particles were characterized by SEM and XRD. Also, the products of the reaction were assigned by GC, GC/MSD and NMR. The particles synthesized by each method showed (1) a spherical shape with the size of 3.2 to $7.0{\mu}m$, (2) an agglomerated spherical shape with the size of 50 to 500 nm and (3) a spherical shape with smaller particle size, respectively. Especially, in order to control the size of particles, the particles were synthesized in various dispersant solutions as Span 80, polyacrylate, and polyethyleneglycols (PEGs). The particles synthesized in PEG (Mw = 4000) solution showed the smallest particle size of 30 to 50 nm and the regularity of the particle size distribution. Our experimental results elucidated that the activity of catalyst for hydrogenation increases with decreasing the size of catalyst particle. The highest yield of dodecanol in the hydrogenation reaction was 95.5% when copper chromite synthesized in the PEG solution was used as a catalyst in the optimized reaction condition.

The Characterizations of Tape Casting for Low Temperature Sintered Microwave Ceramics Composite (저온소성 마이크로파 유전체 세라믹스 복합체의 Tape Casting특성)

  • Lee, Woo-Suk;Kim, Chang-Hwan;Ha, Mun-Su;Jeong, Soon-Jong;Song, Jae-Sung;Ryu, Bong-Ki
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.2 s.273
    • /
    • pp.132-139
    • /
    • 2005
  • Sintering behavior of $BaO-Nd_{2}O_3-TiO_2$ with a Pb-based glassceramics frit were investigated in order to understand an effect of glassceramics as a low temperature sintering agent on dielectric ceramics. A green sheet form was fabricated through tape casting method with the glassceramic fut added $BaO-Nd_{2}O_3-TiO_2$. The dispersion properties, rheological properties and final density of dielectric composit slurry as a function of amount and composition of organic additives was examined. The dispersants' addition was effective in controlling dispersion of the ceramics in solution. The addition of excessive dispersant showed adverse effect on dispersion. The prepared slurries, containing ceramic : powders, glass-ceramics and various kinds of organic viechles, exhibited typical shear thinning behavior. The best properties of tape casting appeared powder to solvent ratio 65 : 35 and amount of the binder 6 wt$\%$ and plasticizer 3 wt$\%$. The viscosity of the slurry was 677 cps and green/sintered density in the tape was $3.3 g/cm^3,\;5.56 g/cm^3$ respectively.

The Preparation of porous ceramic material from aluminum waste dross (알루미늄 廢드로스를 活用한 세라믹 多孔體의 製造)

  • Kim, Ki-Seok;Park, Jay-Hyun;Park, Jai-Koo
    • Resources Recycling
    • /
    • v.14 no.2
    • /
    • pp.19-27
    • /
    • 2005
  • The recycling possibility of aluminum waste dross(AWD) as a ceramic raw material of porous light-weight material was examined. A aluminum waste dross was washed 4-7 consecutive times and roasted at 900$^{\circ}% for 1hour as pre-treatments. The properties of the pre-treatment of aluminum waste dross was investigated. It was conformed by XRD result that the spinel crystalline was grown in AWD, after roasting. After the roasted AWD was ground in aqueous state, the sodium hexaphosphate(SHP) as a dispersant which is used for stabilizing the concentrated slurry was added to the AWD slurry. The porous material was prepared by slurry foaming method with surfactant at room temperature. The foamed slurry volumes were 2 and 3 times of the original slurry volume. The properties of porous material with extended volume of 3 times was following: the porosity was about 84%, bulk density was 0.59 g/cm$^3$, the range of pore was from 50 ${\mu}m$ to 500 ${\mu}m$ and mean pore size was about 200 ${\mu}m$. AWD porous material was sintered at 1150$^{\circ}C-1250$^{\circ}C. It was colcluded that AWD was sintered well at 1200$^{\circ}C from material surface observation by SEM.

Preparation of ZnO Nano Powder and High-transparent UV Shielding Dispersion Sol (ZnO 나노분말 및 고투명성 자외선 차단 분산 졸의 제조)

  • Lee, Hun Dong;Kim, Jin Mo;Son, Dae Hee;Lee, Seung-Ho;Park, Seong Soo
    • Applied Chemistry for Engineering
    • /
    • v.24 no.4
    • /
    • pp.391-395
    • /
    • 2013
  • In this study, zinc oxide (ZnO) nano powder, well known as an UV absorbing material, was synthesized with three synthetic conditions by the hydrothermal method. After ZnO nano powder was surface-modified with various silane coupling agents to improve dispersion property, a dispersion sol was prepared with dispersant for 72 h by the ball-milling of surface-modified ZnO nano powder. The dispersion sol, prepared by modifying the surface of the ZnO nano powder with an average size of about 30 nm using 3-chloropropyl trimethoxy silane, showed an excellent dispersion stability with a high UV-shielding and visible trnasparency.

Effects of particle size on processing variables and green microstructure in gelcast alumina green bodies (겔-케스팅한 알루미나 성형체에서 출발입도가 공정변수 및 성형 미세구조에 미치는 영향)

  • Ha, Chang-Gi;Kim, Jae-Won;Jo, Chang-Yong;Baek, Un-Gyu;Jeong, Yeon-Gil
    • Korean Journal of Materials Research
    • /
    • v.11 no.10
    • /
    • pp.869-878
    • /
    • 2001
  • Alumina $(Al_2O_3)$ green bodies were fabricated by gel-casting using three kinds of alumina with different particle size (mean particle size: 4.6 $\mu\textrm{m}$, 0.32 $\mu\textrm{m}$, 10nm). The effects of particle size on gel-casting process and green microstructure were investigated. The optimum dispersion conditions using ammonium salt (D-3019) as dispersant were 0.2 wt% (4.63 $\mu\textrm{m}$), 0.5 wt% (0.32 $\mu\textrm{m}$), and 5.0 wt% (10 nm), in high solid loading. The optimum solid loading of each starting material for gel-casting was obtained as 59 vol% (4.63 $\mu\textrm{m}$), 57 vol% (0.32 $\mu\textrm{m}$), 15 vol% (10 nm), depending on particle size, indicating that nano-size particle (10 nm) represent lower solid loading as high specific surface area than those of other two starting materials. The drying at ambient conditions (humidity; $\thickapprox$90%) was performed more than 48hrs to enable ejection of the part from the mold and then at $120^{\circ}C$ for 2hrs in an air oven, showing no crack and flaw in the dried green bodies. The pore size and distribution of the gelcast green bodies showed the significant decrease with decreasing particle size. Green microstructure was dependent on the pore size and distribution due to the particle size, and on the deairing step. The green density maximum obtained was 58.9% (4.63 $\mu\textrm{m}$), 60% (0.32 $\mu\textrm{m}$), 47% (10 nm) theoretical density (TD), and the deairing step applied before gel-casting did not affect green density.

  • PDF

Development of Ceramic Membrane for Metal Ion Separation of Lignin Extract from Pulp Process (펄프공정으로부터 배출되는 리그닌 추출물의 금속이온 분리를 위한 세라믹 분리막 개발)

  • Shin, Min Chang;Choi, Young Chan;Park, Jung Hoon
    • Membrane Journal
    • /
    • v.27 no.2
    • /
    • pp.199-204
    • /
    • 2017
  • In this study, a study was carried out for the separation of metal ions in lignin extract discharged from the pulp process. alumina powders were mixed with DMAc (N, N-dimethylacetamide) solvent and PESf (Polyethersulfone) polymer, PVP (polyvinylpyrrolidone) dispersant was added and slip casting method was used to prepare the membrane. The membrane was measured for pore size through a CFP (Capillary Flow Porometer) device and the surface and cross-section of the membrane were observed through a FE-SEM (Field Emission Scanning Electron Microscope). The flux was calculated by measuring the filtered weight per hour using a separation experiment device. Pore size measurements were performed under increasing pressure from 0 psi to 30 psi. The pore size of the membrane was $0.4{\mu}m$ and the flux decreased from the initial flux value of $6.36kg{\cdot}m^{-2}{\cdot}h^{-1}$ to $1.98kg{\cdot}m^{-2}{\cdot}h^{-1}$ due to the fouling of the membrane. After the permeation experiment, membrane contaminants were removed by simple washing. Separation experiments showed that Na contained in the initial lignin extract was reduced by 69%, Fe was removed by 87%, K by 95%, Ca by 93% and Mg by 96%.