Fabrication of Transparent Dielectric Green Sheet for Plasma Display Panel

Heo, Sung-Cheol,Park, Duck-Kyun,Oh, Young-Jei The Korean Ceramic Society 2004 한국세라믹학회지 Vol.41 No.4

Plasma Display Panel(PDP) 상판용 투명유전체의 green sheet를 제조코자 투명유전체 슬러리의 분산특성 및 유기물의 함량과 조성비에 따른 밀도와 기계적 특성을 연구하였다. 비수계 시스템에서 슬러리의 완전분산을 위한 분산제의 종류와 분산제의 양을 결정하기 위해 침강실험, 점도측정을 행하여 최적의 분산조건을 구하였다. 조성물 변수로서 투명유전체조성 분말/(투명유전체조성 분말+유기물)의 비와 결합제/(결합제+가소제)의 비를 각각 변화시켜 green sheet를 제조하였다. 제조된 tape casting 슬러리의 대부분은 의가소성(pseudoplastic) 거동을 보이는데, 의가소성 거동은 shear thinning의 효과를 가지는 것으로 기술 할 수 있다. 각각의 조성을 가지는 슬러리는 모두 전단속도가 증가함에 겉보기 점도가 감소하는 shear thinning 효과를 보여 주었다. Green sheet의 특성을 조사한 결과 유기물의 함량 및 조성이 green sheet의 밀도와 기계적 특성을 결정하는 중요한 인자가 되었다. 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.

Tape Casting법에 의한 PMS-PZT계 세라믹스 제조 및 전기적 특성

정현제,나은상,최성철,Jung, Hyun-Jae,Na, Eun-Sang,Choi, Sung-Churl 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.9

본 논문은 출발물로서 2mol% CdO가 치환된 $0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48})O_3$ 분말을 제조 후, 닥터 블레이드 방법으로 green sheet를 제조하기 위한 slurry의 최적 공정첨가제 조성에 관한 연구를 수행하였다. 또한, 제조된 green sheet에 대하여 소결 특성과 두께 변환에 따른 유전 및 압전 특성을 관찰하였다. 공정첨가제의 첨가에 따른 점도거동을 통하여 slurry를 최적화하였고, TGA 분석으로 소결조건을 정하였으며, sheet의 특성에 미세구조와 XRD 등으로 측정하였다. 최적의 slurry는 고형분량 30vol%에 대해 분산제 3.0wt%에서 가장 안정화되었고, 이후 바인더/가소제(0.75/0.25) 3.0wt% 첨가시 점도는 7.55Pa${\cdot}$s이었다. Green sheet의 유전 및 압전 특성들은 각각 900$^{\circ}$C, 950$^{\circ}$C, 1000$^{\circ}$C로 소결온도를 증가함에 따라 다소 증가하였지만, 두께에 따른 특성들은 큰 변화가 관찰되지 않음을 확인하였다. After manufacturing 2mol% CdO substitute $0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.95Pb(Zr_{0.52}Ti_{0.48})O_3$ piezoelectric ceramics powder as starting material, to manufacture green sheets using Doctor Blade method. The optimum composition of slurry was studied. Moreover, the sintering properties and the dielectric and piezoelectric properties with variation a thickness of the manufactured sheets were investigated. The optimum of slurry was investigated by the rheology with addition of additives, the sintering condition was decided by TGA. And the properties of sheet were investigated through SEM. XRD. The optimum of slurry was the stablest at dispersant 3.0 wt% to solid loading 30vol%. After, at addition of binder/plasticizer(0.75/0.25) 3.0wt%, viscosity was 7.55Pa${\cdot}$s. The dielectric and piezoelectric properties of the sheet were increased a little with the increasing of sintering temperature but were not variable with variation of sheet thickness.

Layer separation behavior in Ni-Zn-Cu Ferrite Green Sheets with Using Poly (butyl methacrylate) copolymer

Shi Yeon Kim,신효순 한양대학교 세라믹연구소 2015 Journal of Ceramic Processing Research Vol.16 No.5

The increasing use of NFC antennae in mobile phones has led to the increase in usage of ferrite sheets. In accordance with the trend for mobile terminals to be high intensity and to have thinner layers, and the need for high-strength materials that can withstand external shocks has increased In this study, the manufacturing process of the green sheet was optimized by using PVB and acrylate binder in the ferrite sheet fabrication process. In this process, a skin forms on the sheet surface in the acrylate binder drying process. This phenomenon was determined to be caused by non-uniform drying due to the high Peclet number of the acrylate binder. In order to resolve this skin problem in the drying process, change in Tg was induced by varying the plasticizer content in the binder. Its relationship with the layer separation phenomenon was defined. As a result, layer separation was reduced by increasing the P/B ratio, and fabrication of a uniform sheet was possible when the P/B ratio was 0.5. Also, layer separation was reduced when using a binder of lower molecular weight among the various acrylate binders. This result was in good agreement with the reported effects related to the Peclet number. Furthermore, changes in the binder distribution state within the sheet, binder adhesion condition, and mechanical properties of the green sheet were observed according to the P/B ratio variation.

중, 고압용 적층 세라믹 캐패시터 제작 및 분석

윤중락,김민기,이헌용,이석원,Yoon, Jung-Rag,Kim, Min-Ki,Lee, Heun-Young,Lee, Serk-Won 한국전기전자재료학회 2005 전기전자재료학회논문지 Vol.18 No.8

In the fabrication and design of MLCCs (Multilayer Ceramic Capacitors) with Ni inner electrode for medium and high voltage, reliability and dielectric breakdown mode have been investigated. For thickness of green sheet, the relationship between the rated voltage versus the thickness of green sheet. Increasing the thickness of green sheet increases the dielectric breakdown voltage. However, a practical limit to this linear relationship occurs at 30 urn and above. As the thickness of green sheet increased, dielectric breakdown voltage and weibull coefficient is increased, but abruptly decrease at 30 urn and 36 urn. When 24 urn of green sheet thickness, weibull coefficient and dielectric breakdown voltage were 13.58 and 70 V/um respectively. The results enabling the MLCCs to demonstrate high levels of reliability at medium and high voltage.

바인더 유리전이온도에 따른 그린시트의 물리적 특성

권혁중,여동훈,신효순,Kwon, Hyeok-Jung,Yeo, Dong-Hun,Shin, Hyo-Soon 한국전기전자재료학회 2013 전기전자재료학회논문지 Vol.26 No.1

The properties of LTCC green sheets formed by the MLS-22 powder of NEG Inc. were investigated for acrylic binders with different PVB and Tg in the variation of temperature. The elongation of the green sheets showed large variation depending on the temperature, and was rapidly decreased near the Tg of the sheets. With the increase of the ratio of plasticizer/binder (P/B), large elongation of the sheets was observed due to the decrease of the Tg. In the stacking process of the multilayer ceramic, the optimal control of the temperature is highly required depending on the Tg of the binder and the ratio of P/Buniform coating.

PDP용 무연 투명유전체의 Dry Film 개발

방재철(Bang Jae-Cheol),이지훈(Lee Ji-Hun) 한국산학기술학회 2005 한국산학기술학회논문지 Vol.6 No.6

Dry film 공정에 의해 PDP(Plasma Display Panel)용 무연 투명유전체를 제조하였다. 여러 슬러리 조성으로부터 고밀도 green sheet를 제조하는데 최적의 조성을 선정하였다. 한편, 슬러리는 양질의 green sheet를 제작하는데 적합한 shear thinning 특성을 나타냈다. 제조한 투명유전체의 열팽창계수는 유리기판인 PD-200과 유사한 97×10^-7℃로측정되었다. PD-200에 접합된 투명유전체의 단면 주사현미경 관찰로부터 두 층은 캡이 없이 매우 견실히 접합되어 있음을 확인할 수 있었다. Dry film method was applied to fabricate lead-free transparent dielectric for PDP(Plasma Display Panel). From various slurry compositions, it was able to find out the- best composition for producing high density green sheet. The slurry exhibited shear thinning characteristics which are known to be suitable for producing a high quality green sheet. The thermal expansion coefficient of the fabricated transparent dielectric was measured to be 97×10^-7℃ which is close to the value of the glass substrate(PD-200). Cross sectional SEM of the transparent dielectric layer on PD-100 showed that the two layers were wen attached each other with no observable gaps between them.

Zn₃V₂O₈ porous morphology derived through a facile and green approach as an excellent anode for high-energy lithium ion batteries

Sambandam, Balaji,Soundharrajan, Vaiyapuri,Song, Jinju,Kim, Sungjin,Jo, Jeonggeun,Pham, Duong Tung,Kim, Seokhun,Mathew, Vinod,Kim, Jaekook Elsevier 2017 Chemical engineering journal Vol.328 No.-

<P><B>Abstract</B></P> <P>Zn<SUB>3</SUB>V<SUB>2</SUB>O<SUB>8</SUB> (ZVO) with sheet-like morphology is synthesized by a simple green precipitation technique via a metal-organic framework (MOF) intermediate for use as an anode in high energy lithium-ion batteries (LIBs). This sheet-like morphology, enriched with highly porous features, is evident from transmission electron microscopy (TEM) and surface area measurements. When tested as a lithium half-cell electrode, the ZVO porous sheets delivered a reversible specific capacity of 1228mAhg<SUP>−1</SUP> at a current density of 0.3Ag<SUP>−1</SUP> for 200 cycles. Interestingly, on applying two different high current densities of 1 and 3Ag<SUP>−1</SUP>, this porous ZVO material registered high capacities of 665 and 510mAhg<SUP>−1</SUP>, initially for 30 and 50 cycles, respectively. On reducing the current density to 0.5 and 1Ag<SUP>−1</SUP> for the two instances, both sustained stable capacities of 906 and 687mAhg<SUP>−1</SUP> in the 160th and 600th cycles, respectively. The fact that these porous sheets maintained a stable capacity as high as 370mAhg<SUP>−1</SUP> at the high applied current density of 5Ag<SUP>−1</SUP> after 2000 discharge/charge cycles reveals the structural stability of the ZVO prepared by a simple green precipitation technique.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Zn<SUB>3</SUB>V<SUB>2</SUB>O<SUB>8</SUB> porous sheets morphology are synthesized by facile and green method. </LI> <LI> It shows excellent structure and electrochemical stability for lithium ion batteries. </LI> <LI> It delivers specific capacity of 1128mAhg<SUP>−1</SUP> after 200 cycles at 0.3Ag<SUP>−1</SUP>. </LI> <LI> It shows high capacity of 370mAhg<SUP>−1</SUP> over 2000 cycles at 5Ag<SUP>−1</SUP>. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

고유전율/저유전율 LTCC 동시소성 기판의 휨 현상

조현민,김형준,이충석,방규석,강남기,Cho, Hyun-Min,Kim, Hyeong-Joon,Lee, Chung-Seok,Bang, Kyu-Seok,Kang, Nam-Kee 한국마이크로전자및패키징학회 2004 마이크로전자 및 패키징학회지 Vol.11 No.3

In this paper, warpages of heterogeneous LTCC substrates comprised of high K/low K hi-layered structure were investigated. The effect of glass content in high K LTCC layer on the warpage of substrate during co-firing process was examined. Shrinkage and dielectric properties of high K and low K green sheets were measured. In-situ camber observation by hot stage microscopy showed different camber development of heterogeneous LTCC substrates according to glass content in high K green sheet. High K green sheet containing $50\%$ glass was matched to low K green sheet in the shrinkage. Therefore, LTCC substrate of Low K/High K+$50\%$ glass structure showed flat surface after sintering. 본 연구에서는 고유전율(K100) 및 저유전율(K7.8) LTCC(Low Temperature Co-fired Ceramics) 그린 시트를 이종 LTCC 기판으로 동시 소성하는 경우, 고유전율 LTCC 내의 유리 분말 함유량에 따라 발생하는 수축 거동 변화가 이종 LTCC기판의 휨 특성에 미치는 영향에 대하여 평가하였다. 유리 분말 함유량의 증가에 따른 고유전율 LTCC 그린시트의 수축률 및 유전 특성을 측정하였으며, 고유전율/저유전율 비대칭형 적층체의 소결 거동을 고온 현미경을 이용하여 실시간으로 측정하였다. $50\%$ 유리가 첨가된 K100 조성의 경우 수축 개시 온도 및 수축 구간의 범위 , 최종 수축률이 K7.8 조성과 유사하였으며, 동시 소성 시 가장 우수한 휨 특성을 나타내었다.

Greenhouse Test Results for Two Years of Sheet‐shaped Root Barrier Materials Apply to Green Roof System for Sustainable Building Construction

장대희,김현수,최수경 한국건축시공학회 2011 한국건축시공학회지 Vol.11 No.6

Recently, As a part of urban forestation, the introductions of green roofs into public projects has been actively driven. Supported by this policy, the sizes of domestic green roof‐related markets have been rapidly expanding and many types of root barrier materials developed in Korea or abroad are being commercially distributed. In this study,root barrier tests were conducted over two years with nine types of sheet type waterproof materials that are the most commonly used as root barrier layers in green roof systems. The test conditions prepared considered the climates,natural features and vegetation in Korea and the results and related root barrier performance were verified. From the results of this study, the necessity to improve the joint part of root barrier sheets and forming methods has been identified and a measure to improve domestic root barrier testing methods was proposed.

Stochastic Green’s theorem for fractional Brownian sheet and its application

김윤태,전종우 한국통계학회 2012 Journal of the Korean Statistical Society Vol.41 No.2

By using the white noise theory for fractional Brownian sheet, we prove the stochastic Green’s theorem with respect to fractional Brownian sheet with Hurst parameters H1, H2 ∈ (0, 1). As an application, we derive an Itô formula for fractional Brownian sheet with H1, H2 ∈ (0, 1).