조명산업의 현황과 미래

윤만순,Yun, Man-Sun 한국전기전자재료학회 2008 전기전자재료 Vol.21 No.1

A-site Ca 및 B-site Zr 첨가에 의한 BaTiO₃-CaTiO₃복합체의 유전특성 및 미세구조에 미치는 영향

윤만순,박영민 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.1

The dielectric and sintering characteristics of composites made by substituting Ca ion to Ba-site and Zr ion to Ti site in $(Ba{1-x}Ca_x)(Ti{0.96-yZr_ySn_{0.04})O_3$ $(0.15{\leq}x{\leq}0.20,\;0.09{\leq}y{\leq}0.14)$ were investigated. As the content of Ca was more than 15 mol%, composite was formed by precipitating the second phase whose main element was $CaTiO_3$ and the fraction of the second phase was increased. The curie temperature of composites was depended on Ca concentration, $-1.7^{\circ}C$ per mol% and the maximum dielectric constant of composite was decreased by the rate of 200/mol%. The substitution of Zr ion decreased the curie temperature by the rate of $10^{\circ}C$ per mol% and the maximum dielectric constant was decreased by 217/mol% due to the increase of diffuse phase transition. The density and insulation breakdown characteristics were improved by suppressing the abnormal grain growth due to the increase of second phase. We developed the composition of Y5U (EIA standard) condenser which had high breakdown voltage and dielectric constant by controlling diffuse phase transition by the addition of Zr ion into composite. $BaTiO_3$의 Ba 자리에 Ca, Ti 자리에 Zr을 첨가한 $(B a_{1-x}Ca_x)(Ti_{0.96-y}Zr_{y}Sn_{0.04})O_3$ $(0.15 {\leq} x{\leq}0.20,\; 0.09{\leq}y{\leq}$0.14) 조성에 2차상 형성을 유도하여 복합체를 만든 후 유전 및 소결 특성을 조사하였다. Ca량이 15mol% 이상 첨가됨에 따라 $CaTiO_3$를 주성분으로 하는 2차상이 석출하여 복합체가 형성되었으며, Ca량의 증가에 따라 2차상 분율이 증가하였다. Ca량의 증가는 큐리 온도를 mol%당 $1.7^{\circ}C$ 감소시키며, 저유전율 2차상의 영향으로 Ca량 증가에 따라 최대 유전율은 mol%당 200 감소하였다. Zr 첨가는 큐리온도를 mol%당 $10^{\circ}C$ 감소시키며, 확산형 상전이 현상을 증가시켜 최대 유전율을 217 감소시켰다. 2차상의 증가에 의하여 비정상 입성장이 억제되어 소결밀도, 내전압 특성이 향상되었으며, Zr 첨가에 의하여 커패시턴스의 온도 안정성을 제어하여 EIA 규격을 만족하는 고압, 고유전율 Y5U 콘덴서 조성을 개발하였다.

교류강전계가 PSN-PZT 압전체의 압전 및 유전 특성에 미치는 non-180$^{\circ}$분역 효과

윤만순,채홍인 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.9

본 연구는 3mol% Pb(Sb$_{1}$2/Nb$_{1}$2/)O$_3$가 첨가된 상경계 영역의 Pb(Zr,Ti)O$_3$(PSN-PZT) 세라믹스에 대하여 RT66A와 광섬유센서를 이용하여, 교류강전계 하에서 압전 및 유전특성을 조사하였다. PSN-PZT 세라믹스의 압전 및 유전 특성에 미치는 non-180$^{\circ}$분역 재배열의 영향을 평가하기 위하여 RT66A와 MTI-2000 Fotonic$^{TM}$ sensor를 이용하여 인가전계와 주파수의 함수로 전계유기변위를 측정하였다. 그 결과, 교류강전계 하에서 전계유기변위는 강전계, 저주파수에서 큰 이력현상을 나타내고, 전계유기변위로부터 결정된 유효압전상수는 주파수가 감소할수록 증가하는 거동을 나타내고 있으며, 이러한 거동은 non-180$^{\circ}$분역 재배열의 영향으로 해석되었다.

전단형 가속도센서에 사용되는 PLZTN 재료 개발

윤만순,임종인,김선욱,장세주 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.1

Piezolectric ceramics of Pb(Zr, Ti)O3 system were fabricated and used for shear type accelerometer. Among compositions studied, La+3 and Nb+5 doped composition showed the highest d15, and K15 and the morphotropic phase boundary (M.P.B) was shifted toward rhombohedral site.

$PbZrO_3$가 첨가된 $Pb(Ni_{1/3}Nb_{2/3})O_3-PbTiO_3$ 계의 미소-거시 분역 반전과 열탄성 마르텐사이트 변태

윤만순,장현명 한국세라믹학회 1995 한국세라믹학회지 Vol.32 No.9

The possiblity of the existence of a spontaneous relaxor-normal ferroelectric transition was proposed and examined using 1~5 mol% PbZrO3-doped Pb(Ni1/3Nb2/3)O3-PbTiO3 (PNN-PT) systems having tetragonal symmetry at rom temperature. On cooling, the system with 60mol% Pb(Ni1/3Nb2/3)O3 underwent a spontaneous transition from a relaxor to a normal ferroelectric state. A microscopic examination demonstrates that the relaxornormal ferroelectric transition corresponds to a micro-macro domain switching accompanied with thermoelastic martensitic transformation. The long-range macrodomains below the transition temperature were characterized by twinlike 90$^{\circ}$macrodomains with tetragonal symmetry. The relaxor-normal ferroelectric transition was further correlated with the rhombohedral-tetragonal first-order structural transition.

$0.6Pb(Ni_{1/3}Nb_{2/3})O_3-0.31PbTiO_3-0.09PbZrO_3$ 완화형 강유전체의 전계 유기 상전이 현상

윤만순,장현명,정회승,최병철 한국세라믹학회 1997 한국세라믹학회지 Vol.34 No.6

The possibility of the existence of a field-induced micro-macrodomain switching was proposed and examined using 9 mol % PbZrO3-doped 0.6Pb(Ni1/3Nb2/3)O3-PbTiO3 (PNN-PT) systems having rhombohedral symmetry at room temperature. the thermally depoled (freshly prepard) specimens prepared from the rhombohedral side of the system exhibited a relaxor behavior for the whole range of temperature examined (for T<Tmax), where its MPB is 6 mol% for PbZrO3. However, a micro-macro ferroelectric domain switching was induced by the aging after prepoling (30 kV/cm) at certain critical temperature below Tmax. Examination of the electric field-induced strain and polarization indicated the existence of a "fuzzy" transition zone under the ac high-field between critical (pseudo-Curie) temperature and Tmax. The observed "fuzzy" characteristics were then correlated with a possible existence of the dynamic field-induced quasimacrodomains below Tmax.odomains below Tmax.

PSN-PMN-PZT 조성의 CeO₂첨가에 따른 압전.유전특성 변화

윤만순,최용길,어순철,Yoon, Man-Soon,Chio, Yong-Gil,Ur, Soon-Chul 한국전기전자재료학회 2006 전기전자재료학회논문지 Vol.19 No.9

0.03Pb$(Sb_{0.5}Nb_{0.5})O_{3}-0.03Pb(Mn{1/3}Nb{2/3)O_{3}-(0.94-x)PbTiO_{3}-xPbZrO_{3}$ ceramics doped with $CeO_{2}$ were synthesized by conventional bulk ceramic processing technique. Phases analysis, microstructures and piezoelectric properties were investigated as a function of $CeO_{2}$ content (0.03, 0.05, 0.1 0.3, 0.5 and 0.7 wt%). Microstructures and phases information were characterized using a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Mechanical quality factor ($Q_{m}$) and coupling factor(kp) were obtained from the resonance measurement method. Both $Q_{m}$ and $k_{p}$ were shown to reach to the maximum at 0.1 wt% $CeO_{2}$. In order to evaluate the stability of resonance frequency and effective electromechanical coupling factor ($K_{eff}$) as a function of $CeO_{2}$, the variation of resonance and anti-resonance frequency were also measured using a high voltage frequency response analyzer under various alternating electric fields from 10 V/mm to 80 V/mm. It was shown that the stability of resonance frequency and effective electromechanical coupling factor were increased with increasing the $CeO_{2}$ contents.

전단형 가속도센서에 사용되는 압전재료 개발

윤만순,임종인,김선욱,백성기,장세주 경북대학교 센서기술연구소 1991 센서技術學術大會論文集 Vol.2 No.1

진단형 가속도센서에 사용될 수 있는 Pb(Zr,Ti)O_(3)계의 압전세라믹스를 제조하였다. 연구된 조성중 La^(+3),Nb^(+5)가 첨가된 조성이 가장 우수한 d_(15),K_(15)값을 갖고 있었으며 La^(+3)첨가에 의하여 상경계는 능면체정계로 이동하였다. Piezoelectric ceramics of Pb(Zr,Ti)O_(3) system were fabricated and used for shear type accelerometer. Among compositions studied , La^(+3) and Nb^(+5) doped composition showed the highest d_(15), and K_(15) and the morphotropic phase boundary (M.P.B) was shifted toward rhombohedral site.

무연 BNBT 세라믹스의 압전특성에 미치는 La₂O₃의 영향

손영진,윤만순,어순철,Son Young-Jin,Yoon Man-Soon,Ur Soon-Chul 한국재료학회 2005 한국재료학회지 Vol.15 No.12

A lead free piezoelectric material, bismuth sodium barium titanate $(Bi_{0.5}Na_{0.5})_{0.94}Ba_{0.06}TiO_3$ (BNBT), was considered as an environment-friendly alternatives for the current PZT system. A perovskite BNBT was synthesized by conventional bulk ceramic processing technique. In order to improve piezoelectric properties, $La_2O_3$ as a dopant was incorporated into the BNBT system up to 0.025 moi, ana the effects on subsequent the piezoelectric ana dielectric properties were systematically investigated. With increasing $La_2O_3$ contents, the equilibrium grain shape was remarkably evidenced and sintered density was increased. Piezoelectric and dielectric properties were s]town to have maximum values at the $La_2O_3$ contents of 0.02 mol. $La^{3+}$ ions seemed to act as a softener in the BNBT system and to enhance dielectric and piezoelectric properties in this study.

Sol-Gel Processing에 의한 순수 $PbTiO_3$ Ceramics 제조

김선욱,윤만순,임종인,김성숭,김남흥 한국세라믹학회 1992 한국세라믹학회지 Vol.29 No.3

Crack free PbTiO3 ceramics were produced by sol-gel processing using alkoxide, which has not been reported to be successful. The PbTiO3 gels were prepared from Ti alkoxide and lead acetate without any dopants. They were calcined at $600^{\circ}C$ and miled to produce fine PbTiO3 powder. It was pressed into discs and they were sintered at 110$0^{\circ}C$ for a few hours. The sintered ceramics were relativley hard and dense as having about 96% of theoretical density of PbTiO3. Fabrication of pure PbTiO3 ceramics by sol-gel processing is possibly due to their small grain size and uniform distribution of residual stress created during cubic-tetragonal transition over large number of small grains in fine grain PbTiO3 ceramics.