• 한국세라믹학회지
• /
• 제35권5호
• /
• pp.458-464
• /
• 1998

Variations of reaction sequence of $Pb(Zn_{0.6}Mg_{0.4})_{1/3}Nb_{2/3}O_3$[PZMN] with precusor mixing methods were ex-amined using X-ray diffraction and dielectric characteristics. In the present study three different types of precursor mixing methods (oxide mixing PbO+$ZnNb_2O_6+MgNb_2O_6$[Zn+MN] and PbO+(Zn,Mg)$Nb_2O_6$[ZMN] precursor mixing) were adopted. When the oxide mixing method was used for the PZMN synthesis a Zn-rich perovskite phase and pyrochlore phase were formed. Compared with PbO+ZN+MN precursor mixing method the PbO-ZMN precursor led to a lowering of the formation temperature for perovskite sin-gle phase. These variation of composition and formation temperature of the perovskite phase were dis-cussed in terms of the difference in the solid-reaction requence between these three different types of pre-cursor mixing.

• 한국결정학회지
• /
• 제13권3_4호
• /
• pp.172-176
• /
• 2002

Pb(Mg /sub 1/3/Nb/sub 2/3/)O₃-PbTiO₃ 계 완화형 강유전체에서 PbTiO₃ 첨가량 변화 및 온도 변화에 따른 상전이 거동을 초전특성 및 유전완화현상 고찰을 통해 고찰하였다. -40∼200℃의 상전이 온도범위에 걸쳐 초전 및 유전특성을 살펴보았으며 특히 Vogel-Fulcher 관계식에 의한 freezing temperature를 도출하였다. 이러한 모든 실험적 결과들로부터 기존에 제안되었던 Pb(Mg /sub 1/3/Nb/sub 2/3/)O₃-PbTiO₃ 고용체 시스템에 대한 상평형도를 다소 수정하여 제안하였다.

• 한국세라믹학회지
• /
• 제36권12호
• /
• pp.1287-1295
• /
• 1999

• 한국세라믹학회지
• /
• 제39권6호
• /
• pp.566-569
• /
• 2002

일반적으로 Pb-계 복합 perovskite형 산화물들은 그 제조과정에서 중간상으로 알려진 pyrochore상을 통하여 최종적으로 합성된다. 본 연구에서는 Pb(Fe$_{1}$2/Nb$_{1}$2/)O$_3$를 대상으로 하여 고유전율, 고순도, 입자크기 및 저온 소결에 알맞은 Pb(Fe$_{1}$2/Nb$_{1}$2/)O$_3$분말을 초임계 유체의 장점과 autoclave내의 분리 반응 실험으로 285$^{\circ}C$,7.2MPa의 조건하에서 제조하였고, 제조되어진 분말들의 제반 특성들에 대하여 조사하였다.

• 한국세라믹학회지
• /
• 제25권5호
• /
• pp.488-494
• /
• 1988

Effects of MnO2 addition on themicrostructure, dielectric and piezoelectric properties of Rhombohedral, Tetragonal and Morphotropic phase boundary(MPB) in Pb(Ni1/3Nb2/3)O3-PbTiO3-PbZrO3 system were investigated and respectively the amount of MnO2 addition was 0, 0.2, 0.5, 1.0, 3.0wt%. In the tetragonal region, compared with the Rhombohedral and Morpotropic phase boundary, Mechanical quality factor(Qm), Curie temperature(Tc) and Dissipation factor were promoted by addition of MnO2. According to the results of the microstructure, dielectric and piezoelectric properties, the solid solution range of MnO2 addition in this system was 0.2-0.5wt%.

• 한국세라믹학회지
• /
• 제37권7호
• /
• pp.673-680
• /
• 2000

The effect of excess PbO(0, 1, 2, 4, and 8 mol%) on grain growth and densification of (65)Pb(Mg1/3Nb2/3)O3-(35)PbTiO3 [mol%] ceramics has been investigaetd. With increasing the amount of excess PbO and sintering time, densities of sintered samples decreased gradually. The samples containing less than 1 mol% of PbO showed normal grain growth behavior, however abnormal grain growth was observed to occur in the samples with more than 2 mol% of PbO. In the samples with more than 2 mol% of PbO, the number of abnormal grains decreased and thus the average grain size became smaller with increasing the amount of excess PbO. These results demonstrated that the abnormal grain growth started to occur when a critical amount of excess PbO was added to a (65)Pb(Mg1/3Nb2/3)O3-(35)PbTiO3 sample. Since PMN-PT grains in a liquid matrix were angular, the observed abnormal grain growth was explained to proceed through the two dimensional nucleation process.

• Applied Science and Convergence Technology
• /
• 제25권4호
• /
• pp.77-80
• /
• 2016

The $PbSc_{1/2}Nb_{1/2}O_3$ ceramics at a relatively low temperature of $1300^{\circ}C$ was successful synthesized. Solid state reaction of two-step process is not necessary. The dielectric constant, dielectric loss and admittance of ceramic samples were determined. The pyroelectric characteristics are in good agreement with the dielectric properties. Ferroelectric properties of well-formed the $PbSc_{1/2}Nb_{1/2}O_3$ ceramics are in agreement with broad distribution of relaxation phenomenon. Relatively strong frequency dependent of dielectric constant is observed at about $110^{\circ}C$. The distinct thermal hysteresis was observed in the measurement of the dielectric constant and dielectric loss. The critical exponents of during cooling and heating measurements in the $PbSc_{1/2}Nb_{1/2}O_3$ ceramics were 1.14 and 1.59 at 1 kHz, respectively.

• 한국세라믹학회지
• /
• 제32권9호
• /
• pp.967-976
• /
• 1995

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.

• 한국세라믹학회지
• /
• 제30권3호
• /
• pp.175-180
• /
• 1993

Influence of Nd3+ substitution for Pb2+ on the dielectric properties and the PbO evaporation according to substituting Nd3+ for Pb2+ in Pb(Mg1/3Nb2/3)O3 system ceramics have been investigated. The dielectric constant at the curie temperature and evaporation of PbO were decreased with increase of Nd3+ amounts. The percentage of PbO evaporation was 2.5wt% in the PMN system substituted Nd3+ for Pb2+, while it was 3.7wt% in the PMN system.

• 한국세라믹학회지
• /
• 제25권4호
• /
• pp.335-340
• /
• 1988

The change in microstructure and the electrical properties of Pb(In1/2Nb1/2)O3-PbTiO3 Ceramics caused by V2O5 addition were studied. The results are ; 1. interability was increased because the mass transport through the second phase formed by V2O5 addition increased. 2. ith addition of V2O5, tetragonality and Curie temperature increased. The maximum value of kp was observed when 0.5wt% of V2O5 was added. 3. he second phase formed by V2O5 accelerated the grain growth, and existed in grain boundary. Electrical properties were changed by corelations between tetragonality and the amount of second phase.