• Title/Summary/Keyword: Ceramic dispersant

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Closed-type Barrier Ribs of PDP via Micro-Molding Process

  • Son, Hyeon-Min;Kim, Sung-Jin;Koh, Min-Soo;Kim, Jin-Seok;Kim, Yong-Seog;Choi, Byung-Do
    • 한국정보디스플레이학회:학술대회논문집
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    • 2005.07a
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    • pp.710-713
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    • 2005
  • In this study, waffle type barrier ribs for counter electrode discharge cells were prepared via micro-molding process. The master mold was prepared by UV lithography and working mold was manufactured by replicating the master mold. The UV paste used in this study consisted of ceramic powders for the barrier ribs, binder, hardener, and dispersant was filled into cavities of a polymeric mold by action of capillary pressure developed between mold and paste. The results demonstrated a possibility of one-step process for the manufacturing of waffle type barrier ribs embedded with sustaining electrodes.

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Effect of Reaction Condition and Solvent on The Size and Morphology of Silica Powder Prepared by An Emulsion Technique

  • Park, Won-Kyu;Kim, Dae-Yong
    • The Korean Journal of Ceramics
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    • v.6 no.3
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    • pp.229-235
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    • 2000
  • The spherical silica powder was synthesized by varying the kinds of solvent and mixing energy in emulsion method. The stirring speed varied from 500 to 1000 r.p.m. at 5$0^{\circ}C$ for 2h. Toluene in benzyl groups and a series of alkanes were used as dispersant. The average size of spherical silica particles decreased with increasing the stirring speed and the chain length o solvents used in this work. The average size was controlled in the range of 134~28$\mu\textrm{m}$ by selecting a proper solvent and stirring speed. The optimum processing parameters were described in details.

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Aqueous Processing of Textured Silicon Nitride Ceramics by Slip Casting in a Strong Magnetic Field

  • Zhu, Xinwen;Uchikoshi, Tetsuo;Sakka, Yoshio
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09b
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    • pp.866-867
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    • 2006
  • This work will report a highly textured ${\beta}-Si_3N_4$ ceramic by aqueous slip casting in a magnetic field and subsequent pressureless sintering, Effects of the sintering aids, polymer dispersant, pH and stirring time on the stability of the $Si_3N_4$ slurries were studied. The textured ${\beta}-Si_3N_4$ with 97 % relative density could be obtained by slip casting in a magnetic field of 12 T and subsequent sintering at $1800^{\circ}C$ for 1 h. The textured microstructure is featured by the alignment of c-axis of ${\beta}-Si_3N_4$ crystals perpendicular to the magnetic field, and the Lotgering orientation factor, f, is determined to be 0.8.

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Acrylamide Polymerization on ceramic Powders(I) : The Process Control of Si2N4 Gelcasting by Polymerization of Acrylamicde (세라믹분체 표면에서 아크릴아마이드 중합(제1보) : 아마이드 고분자중합에 의한 질화규소 겔캐스팅 공정제어)

  • 류병환;김은영;이재도
    • Journal of the Korean Ceramic Society
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    • v.36 no.2
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    • pp.178-185
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    • 1999
  • For the process control of silicon nitride gelcasting, the composition effect of acryamide system on the viscosity of slip and mechanical property of gelcast green body were investigated. The slip was prepared by ball milling of silicon nitride suspension prepared with acrylamide monomer and polyelectrolyte dispersant after premixing them by attritor. The slip mixed with initiator was vacuum deaired and cast into molds, and then polymerized. The consolidated green body was obtained by drying the gelated slip. The viscosity measument and the diametral compression test was done to evaluate the rheological behaviro of slip and mechanical property of gelcast body, respectively. Experimental results showed that the high solid loading of silicon nitride slip was obtained up to 46 vol% with a low viscosity. The mechanical property of gelcast body mainly increased with increasing the concentration of monomer. The gelcast body was machinable above the ∼3 MPa of tensile strength. The relative density of pressured-sintered body was 98.5% at 1760$^{\circ}C$, 3 h.

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Fabrication of Transparent Dielectric Green Sheet for Plasma Display Panel (PDP 투명유전체 형성용 Green Sheet 제조)

  • Heo, Sung-Cheol;Park, Duck-Kyun;Oh, Young-Jei
    • Journal of the Korean Ceramic Society
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    • v.41 no.4
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    • pp.277-283
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    • 2004
  • To fabricate green sheet of transparent dielectric for PDP front panel, dispersion of transparent dielectric slurry, density, and mechanical properties of green sheets have been investigated as a function of amount and composition of organic additives. Measurements of sedimentation and viscosity were employed to determine a proper dispersant and its amount for a well dispersed transparent dielectric powders in non-aqueous system. Green sheets, having various ratios of transparent dielectric powders to transparent dielectric powders+ binder+plasticizer and binder to binder+plasticizer, were fabricated. All the tape casting slurries showed shear thinning effect, that is, the apparent viscosity decreased with the increase of shear rate. It was found that the amount and composition of organic additives were main variables to affect densities and mechanical properties of transparent dielectric green sheets for PDP.

Printing Properties of Ag Paste with the Variation of Binder on the SiNx Coated Si Wafer (SiNx 층이 코팅된 Si Wafer에 바인더 종류에 따른 Ag 페이스트의 인쇄 특성)

  • Kang, Jea Won;Shin, Hyo Soon;Yeo, Dong Hun;Jeong, Dae Yong
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.27 no.2
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    • pp.85-90
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    • 2014
  • Ag paste has been used in the front electrode of the Si-solar cell. It is composed by Ag powder, glass frit, binder, solvent and dispersant. The role of the binder and the solvent is to make a flow and a printing property. However, it was not enough to report the printing properties with the variation of binder in the controled viscosity. In this study, we selected 3 kinds of typical binder which were used as binder for the paste in the industry, such as Ethyl cellulose, Hydroxypropyl cellulose and Acrylic. Ag pastes using these were prepared, controled viscosity and printed on the SiNx coated Si wafer. In the 'A paste' used Acrylic binder, printed hight was highest and 'H paste' used Hydroxypropyl cellulose binder was lowest. Because 'H paste' was high viscosity due to the molecular weight, the solvent was added in the paste to control the viscosity. Therefore, the content of solid was lower in 'H paste'. The relative pattern width which is related to the spreading of paste was the best in the case of 'H paste' and 'EH paste' at $30^{\circ}C$. It is thought that the optimization of the relative pattern width is possible for a paste by the controling shear thinning phenomenon. In the case of 'A paste', though printing hight was best, the pattern width was dependant on the temperature.

Formation of Ti3SiC2 Interphase of SiC Fiber by Electrophoretic Deposition Method

  • Lee, Hyeon-Geun;Kim, Daejong;Jeong, Yeon Su;Park, Ji Yeon;Kim, Weon-Ju
    • Journal of the Korean Ceramic Society
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    • v.53 no.1
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    • pp.87-92
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    • 2016
  • Due to its stability at high temperature and its layered structure, $Ti_3SiC_2$ MAX phase was considered to the interphase of $SiC_f/SiC$ composite. In this study, $Ti_3SiC_2$ MAX phase powder was deposited on SiC fiber via the electrophoretic deposition (EPD) method. The Zeta potential of the $Ti_3SiC_2$ suspension with and without polyethyleneimine as a dispersant was measured to determine the conditions of the EPD experiments. Using a suspension with 0.03 wt.% ball milled $Ti_3SiC_2$ powder and 0.3 wt.% PEI, $Ti_3SiC_2$ MAX phase was successfully coated on SiC fiber with an EPD voltage of 10 V for 2 h. Most of the coated $Ti_3SiC_2$ powders are composed of spherical particles. Part of the $Ti_3SiC_2$ powders that are platelet shaped are oriented parallel to the SiC fiber surface. From these results we expect that $Ti_3SiC_2$ can be applied to the interphase of $SiC_f/SiC$ composites.

Synthesis of Concentrated Silver Nano Sol for Ink-Jet Method (잉크젯용 고농도 은 나노 졸 합성)

  • Park, Han-Sung;Seo, Dong-Soo;Choi, Youngmin;Chang, Hyunjoo;Kong, Ki-Jeong;Lee, Jung-O;Ryu, Beyong-Hwan
    • Journal of the Korean Ceramic Society
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    • v.41 no.9
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    • pp.670-676
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    • 2004
  • The synthesis of highly concentrated silver nano sol assisted by polymeric dispersant (polyelectrolytes) for inkjet method was studied. The silver nano sol was prepared with AgNO$_3$, polyelectrolytes (HS5468cf ; polyacrylic ammonium salt), and reducing agent. The polyelectrolytes play an important role in formation of complex composed of Ag$\^$+/ion and carboxyl group (COO$\^$-/), result in preparation of highly dispersed silver nano particles. The optimization of added amount of polyelectrolytes, and concentration of silver nano sol was studied. The silver nanoparticles were evaluated by XRD, particle size/zeta potential analyzer and FE-TEM. The silver nanoparticles with the range of 10 nm in diameter were produced. The concentration of batch-synthesized silver nano sol was possible up to 40 wt%.

Effect of Adding Graphene/Carbon Nanotubes (FCN) on the Mechanical Properties of Polyamide-Nylon 6 (그래핀/탄소나노튜브(FCN) 첨가에 따른 Polyamide-Nylon 6의 기계적 특성에 미치는 영향)

  • Seung-Jun Yeo;Hae-Reum Shin;Woo-Seung Noh;Man-Tae Kim
    • Journal of the Korean Society of Industry Convergence
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    • v.26 no.6_3
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    • pp.1297-1303
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    • 2023
  • Research on enhancing the mechanical strength, lightweight properties, electrical conductivity, and thermal conductivity of composite materials by incorporating nano-materials is actively underway. Thermoplastic resins can change their form under heat, making them highly processable and recyclable. In this study, Polyamide-Nylon 6 (PA6), a thermoplastic resin, was utilized, and as reinforcing agents, fused carbon nano-materials (FCN) formed by structurally combining Carbon Nanotube(CNT) and Graphene were employed. Nano-materials often face challenges related to cohesion and dispersion. To address this issue, Silane functional groups were introduced to enhance the dispersion of FCN in PA6. The manufacturing conditions for the composite materials involved determining the use of a dispersant and varying FCN content at 0.05 wt%, 0.1 wt%, and 0.2 wt%. Tensile strength measurements were conducted, and FE-SEM analysis was performed on fracture surfaces. As a result of the tensile strength test, it was confirmed that compared to pure PA6, the strength of the polymer composite with a content of 0.05 wt% was improved by about 60%, for 0.1 wt%, about 65%, and for 0.2 wt%, the strength was improved by 50%. Also, when compared according to the content of FCN, the best strength value was shown when 0.1 wt% was added. The elastic modulus also showed an improvement of about 15% in the case of surface treatment compared to the case without surface treatment, and an improvement of about 70% compared to pure PA6. Through FE-SEM, it was confirmed that the matrix material and silane-modified nanomaterial improved the dispersibility and bonding strength of the interface, helping to support the load evenly and enabling effective stress transfer.

Microstructure Analysis with Preparation Condition of Electrolyte Membrane for High Temperature Electrolysis (고온 수전해 전해질 막의 제막조건에 따른 미세구조 분석)

  • Choi, Ho-Sang;Son, Hyo-Seok;Hwang, Gab-Jin;Bae, Ki-Kwang
    • Transactions of the Korean hydrogen and new energy society
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    • v.17 no.2
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    • pp.141-148
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    • 2006
  • This study was carried out to analyze the microstructure characteristics of electrolyte membrane through XRD, SEM and AC impedance measurement for using in high temperature steam electrolysis(HTE). It was investigated that thermal stability and electric characteristics by sintering condition using dry and wet process, and confirmed growth of particle and density change by sintering temperature. The sintering temperature and behavior had an effect on the relative density of the ceramic and the average grain size. The more amount of dispersant in organic compound increase, the more the density increased. But the binder was shown opposite phenomenon. It was analyzed that electrolyte resistance and electrical characteristics using AC impedance. The electrical properties of YSZ grain boundary changed with the sintering temperature.