Rhombohedral상 PZT의 압전성질과 열팽창에 관한 연구

이응상,박현,김기태,Lee, Eung-Sang,Park, Hyun,Kim, Gi-Tae 한국세라믹학회 1989 한국세라믹학회지 Vol.26 No.1

This experiment was conducted to investigate correlation between microstructure and electrical properties according to Zr/Ti mole ratio in Rhombohedral Phase PZT. Domain behavoir was investigated by the change of thermal expansion coefficient. Piezoelectric properties, the temperature dependence of dielectric constant and the change of dielectric constant before and after poling were measured. Crystal structure, the measurement of lattice parameter were carried by X-ray analysis. Domain pattern before and after poling was examined by SEM.

단순 Matrix LCD 기술

이응상,박호영 대한전기학회 1989 전기의 세계 Vol.38 No.10

신실질 절개와 신부분절제술 49례에 대한 임상관찰

이응상,임수길 大韓泌尿器科學會 1979 Korean Journal of Urology Vol.20 No.3

LAS($Li_2O.Al_2O_3.SiO_2$)계 소지의 소결특성에 관한 연구

이응상,박현,김동환,Lee, Eung-Sang,Park, Hyun,Kim, Dong-Hwan 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.2

It has been reported that natural petalite showed a low negative thermal coefficient and wide coefficient and wide coexisting region with liquid phase in Li2O-Al2O3-SiO2 system. Therefore, we investigated variation of microstructure and thermal and mechanical properties when the amount of SiO2 content in petalite compound and MgO addition to it compound were changed. As SiO2 content exceeded 80 wt%, crystal phases of $\beta$-cristobalite and $\beta$-spondumene solid solution were formed. Generally, the densification and bending strength were increased by the addition of MgO, but the positive thermal coefficient was found in the case of MgO 10 wt% addition because of second phase and glassy phase.

ZnO-$SnO_2$계 Spinel 채료에 대한 NiO, $TiO_2$의 영향

이응상,황성윤 한국세라믹학회 1977 한국세라믹학회지 Vol.14 No.3

For the purpose researching to the influence of tetrahedral and octahedral preference of cations of $Ni^{2+}$, $Ti^{4+}$ upon the formation and the color development of the $ZnO-SnO_2$ spinel containing $Ni^{2+}$ and $Ti^{4+}$ ions, the gradual substitution of $Ni^{2+}$ ions for $Zn^{2+}$ ions and of $Ti^{4+}$ ions for $Sn^{4+}$ ions of the spinel in NiO-ZnO-$SnO_2$-$TiO_2$ system was carried out. On samples prepared by calcining the oxide and basic cabonate mixtures at $1300^{\circ}C$ for 2 hours, the X-ray analysis, measurement of reflectance and the test of their stabilaity as a glaze pigment were also carried out. The results are summarized as follows 1) Single spinel was formed completely to x=1 in the $xNiO\cdot(2-x)ZnO\cdot{SnO}_2$system, and gave brilliant lightgreen hue. Moreover, $NiO\cdot{ZnO}\cdot{SnO}_2$ formed easily spinel than $NiO\cdot{MgO}\cdot{SnO}_2$ because Zn^{2+}$ ions had more strong tetrahedral preference than $Mg^{2+}$ ions. 2) As the gradual substitution of $Ti^{4+}$ ions for $Sn^{4+}$ ions in $NiO\cdot{MgO}\cdot{SnO}_2$ system, the spinels formed well and was nearly not changed in the hue. 3) The results of glaze test. (1) As the gradual substitution of $Ni^{2+}$ ions for $Zn^{2+}$ ions, the color changed from dull white to graish broun gradually in calcium-zinc glaze and calcium glaze, and from white to beige in tile glaze. (2) As the gradual substitution of $Ti^{4+}$ ions for $Sn^{4+}$ ions in $NiO-ZnO-SnO_2-TiO_2$ system, the color was become dull generally and was not change in tile glaze.

$MgO-SiO_2$계 자기에 관한 연구

이응상,이종근,임대영,최성철 한국세라믹학회 1982 한국세라믹학회지 Vol.19 No.2

This study has examined closely on the various foundamental conditions for the fitting in steatite porcelain as a industrial porcelain of superior quality, and as a decorated porcelain. The materials consisting of the Kyul Sung talc, and the sea water magnesia clinker power which was produced from Sam Hwa-Hwa Sung, as major constituents have been used, and also used Hyup Jin kaolin as clay minerals to give them plasticity. First, the mixture was made of corresponding in the theoretical composition of enstatite with Kyul sung talc and sea water magnesia clinker, and kaolin was added in various kinds of 1%, 2.5% 5%, 10%, and 20% by weight of the mixture. Next, the mixture was fired at the various temperatures from 1330 to 145$0^{\circ}C$. After we examined closely the physical properties and microstructures, we achieved the results that noted from this study were listed below. 1. The addition amount of kaolin should generally be from 5% to 10% by weight of the mixture to give mixture plasticity in steatite porcelain, but preferably about 20% to consider the firing temperature. 2. The temperature of the optimum firing range is from 1390 C to 142$0^{\circ}C$. 3. A case, which the $A_2$ composition had been fired at 142$0^{\circ}C$, showed a good effect in the strength, but showed a bad result in the absorption. Therefore, the specimens of $A_4$ the composition has excellent in properties of matters when the composition is fired at 142$0^{\circ}C$. Also, we consider that the specimens of the $A_5$ composition, which is fired at 139$0^{\circ}C$, is suitable for the $MgO-SiO_2$ porcelain bodies with respect to the various properties.

Pb($Zn_{1/3}Nb_{2/3}O_3-PbTiO_3-BaTiO_3$) System의 미세구조와 전기적 물성에 관한 연구

이응상,이정우 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.9

The purpose of this investigation was to study the stability of perovskite structure, the variation of electrical properties and a microstructure with varing amount of PbTiO3 additive in PZN-PT-BT system. The results are as follows: 1. The pyrochlore phase was reduced as the amount of PbTiO3 additive was increased and completely eliminated at 0.15PT in PZN-PT-BT system. 2. The aging rate was increased in proportion to tetragonality because the internal stress was increased in proportion to tetragonality. 3. On increasing the amount of PbTiO3 additive, the Curie temperature was increased in proportion to tetragonality. 4. As the amount of PT in the composition increase, the variation of dielectric constant was sharpened and the diffuseness of the transition decreased.

Pb(Fe$_{1/2}$Nb1/2)O$_3$-Pb(Fe$_{2/3}$W$_{1/3}$)O$_3$계에 있어서 MnO2 첨가에 따른 유전적 성질

이응상,김대원 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.1

In the ceramics of PFN-PFW system modified with MnO2 dielectric properties and the relation of its microstructure have been investigated. The amount of MnO2 variations was 0, 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 mol%, respectively. In the result of the microstructure and electrical properties, the solid solution range of MnO2 was 0.15 mol%.

ZTA-SiC whisker계 재료의 기계적 및 구조적 특성

이응상,최성철,정연길 한국세라믹학회 1991 한국세라믹학회지 Vol.28 No.9

ZrO2-Toughened Alumina-Ceramics (ZTA) with SiC Whisker as dispersive additive were prepared by pressureless sintering at 1$600^{\circ}C$ and 1$650^{\circ}C$ and by HIPing at 1$600^{\circ}C$ in Ar atmosphere. Effects of SiC-Whisker addition on microstuructural, mechanical, and thermal properties were investigated and the toughening mechanisms between theory and experiment were compared. Specimens with 15 vol% Whisker prepared by HIPing showed 8.26 MPa.ma1/2 in fracture toughness and 600 MPa in flexural strength owing to contribution of the three mechanisms such as crack deflection, whisker bridging and whisker pullout in spite of difference between the theoretical and experimental values due to the partial inhomogeneous dispersion of SiC-Whisker in the matrix and the processing flaw.

PZT/Polymer 복합재료의 초전 특성에 관한 연구

이응상,안성훈 한국세라믹학회 1990 한국세라믹학회지 Vol.27 No.1

In the present investigation, ceramic PZT and Polymer were prepared. The former is Pb[(Sn1/2Sb1/2)0.1 Ti0.27Zr0.63]O3 including Pb(Sn1/2Sb1/2)O3 with good pyroelectric effect, and the latter PVA(Poly Vinyl Alcohol) with good plasticity. Then, they were fabricated to be flat by using 0-3 connectivity which is rather easily fabricated and capable of making thin film, extending surface area among the connectivities. Such were applied to the sample as variation of intensity of poling field, poling temperature, volume fraction between ceramic and polymer. Then dielectric constant, pyroelectric current, pyroelectric coefficient and the figure of merit were measured. And then their effects on pyroelectric characteristics were observed.