• Title/Summary/Keyword: Ceramics dielectric material

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소결 온도에 따른 비납계 NKN-BNT-BT 세라믹의 전기적, 구조적 특성

  • Lee, Seong-Gap;Nam, Seong-Pil;No, Hyeon-Ji;Bae, Seon-Gi;Lee, Yeong-Hui
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.104-104
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    • 2009
  • In this study, both structural, dielectric and piezoelectric properties of the NKN-0.96BNT-0.04BT ceramics were investigated. All samples of the NKN-0.96BNT-0.04BT ceramics were fabricated by conventional mixed oxide method with Pt electrodes. We report the improved dielectric and piezoelectric properties in the perovskite structure composed of the NKN, BNT and the BT ceramics. We investigated the effects of NKN, BT on the structural and electrical properties of the NKN-0.93BNT-0.07BT ceramics. The dielectric properties and piezoelectric properties of the NKN-0.93BNT-0.07BT ceramics were superior to those of single composition NKN, NKN-BNT and those values for the NKN-0.93BNT-0.07BT ceramics were 861 and 1.12%.

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Correlation between Dielectric Constant Change and Oxidation Behavior of Silicon Nitride Ceramics at Elevating Temperature up to 1,000 ℃ (질화규소 세라믹스의 고온(~1,000 ℃) 유전상수 변화와 산화 거동의 상관관계 고찰)

  • Seok-Min, Yong;Seok-Young, Ko;Wook Ki, Jung;Dahye, Shin;Jin-Woo, Park;Jaeho, Choi
    • Journal of the Korea Institute of Military Science and Technology
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    • v.25 no.6
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    • pp.580-585
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    • 2022
  • In this study, the high-temperature dielectric constant of Si3N4 ceramics, a representative non-oxide-based radome material, was evaluated and the cause of the dielectric constant change was analyzed in relation to the oxidation behavior. The dielectric constant of Si3N4 ceramics was 7.79 at room temperature, and it linearly increased as the temperature increased, showing 8.42 at 1,000 ℃. As results of analyzing the microstructure and phase for the Si3N4 ceramics before and after heat-treatment, it was confirmed that oxidation did not occur at all or occurred only on the surface at a very insignificant level below 1,000 ℃. Based on this, it is concluded that the increase in the dielectric constant according to the temperature increase of Si3N4 ceramics is irrelevant to the oxidation behavior and is only due to the activation of charge polarization.

Structural, Dielectric and Field-Induced Strain Properties of La-Modified Bi1/2Na1/2TiO3-BaTiO3-SrZrO3 Ceramics

  • Hussain, Ali;Maqbool, Adnan;Malik, Rizwan Ahmed;Zaman, Arif;Lee, Jae Hong;Song, Tae Kwon;Lee, Jae Hyun;Kim, Won Jeong;Kim, Myong Ho
    • Korean Journal of Materials Research
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    • v.25 no.10
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    • pp.566-570
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    • 2015
  • $Bi_{0.5}Na_{0.5}TiO_3$ (BNT) based ceramics are considered potential lead-free alternatives for $Pb(Zr,Ti)O_3$(PZT) based ceramics in various applications such as sensors, actuators and transducers. However, BNT-based ceramics have lower electromechanical performance as compared with PZT based ceramics. Therefore, in this work, lead-free bulk $0.99[(Bi_{0.5}Na_{0.5})_{0.935}Ba_{0.065}]_{(1-x)}La_xTiO_3-0.01SrZO_3$ (BNBTLax-SZ, with x = 0, 0.01, 0.02) ceramics were synthesized by a conventional solid state reaction The crystal structure, dielectric response, degree of diffuseness and electric-field-induced strain properties were investigated as a function of different La concentrations. All samples were crystallized into a single phase perovskite structure. The temperature dependent dielectric response of La-modified BNBT-SZ ceramics showed lower dielectric response and improved field-induced strain response. The field induced strain increased from 0.17%_for pure BNBT-SZ to 0.38 % for 1 mol.% La-modified BNBT-SZ ceramics at an applied electric field of 6 kV/mm. These results show that La-modified BNBT-SZ ceramic system is expected to be a new candidate material for lead-free electronic devices.

Dielectric and Piezoelectric Properties of PNN-PZN-PZT Ceramics for Microdisplacement Element Application (미소 변위 소자용 PNN-PZN-PZT 세라믹스와 유전 및 압전특성)

  • 이수호;조현철;박정학;최헌일;사공건
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1996.05a
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    • pp.142-145
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    • 1996
  • In this study, dielectric and piezoelectric properties of 0.5PNN-(0.5-x)PZN-xPZT system ceramics with PZT mole ratio were investigated. As the amount of PZT increases, curie temperature was increased. The maximum of dielectric and piezoelectric constant was shoun at 0.3 mole of PZT amount. As a results, we have found that the structure of ceramics with PZT 0.3 mole was morphotropic phase boundary.

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The Structural and dielectric Properties of the $BaTiO_{3}+10wt%Nb_{2}O_{5}$ ceramics with the sintering temperature (소결온도에 따른 $BaTiO_{3}+10wt%Nb_{2}O_{5}$ 세라믹스의 구조 및 유전특성)

  • 이상철;이성갑;배선기;이영희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.402-405
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    • 2001
  • The BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics were prepared by conventional mixed oxide method. The structural and dielectric properties of the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics with the sintering temperature were investigated. Increasing the sintering temperature, the 2$\theta$ value of BaTiO$_3$peaks were shifted to the higher degree and intensity of the BaTiO$_3$and BaNbO$_3$peaks were increased. In the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics sintered at 135$0^{\circ}C$ and 1375$^{\circ}C$, the grain was fine and uniform. Increasing the sintering temperature, the pore was decreased and the dielectric constant was increased. In the BaTiO$_3$+10wt%Nb$_2$O$_{5}$ ceramics sintered at 1375$^{\circ}C$, the dielectric constant and dielectric loss were 5424, 0.02 respectively.ctively.

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The Influence of $Ta_2O_{5}$ Addition on Dielectric Characteristics of Zirconium Titanate Ceramics (Zirconium Titanate 세라믹 유전체에서 $Ta_2O_{5}$ 첨가가 유전특성에 미치는 영향)

  • 이석진;이창화;이상석;최태구
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1992.05a
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    • pp.129-132
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    • 1992
  • Rutile was among the first dielectric materials used. However, rutile exhibits a very high temperature coefficient of capacitance (about -750[ppm/$^{\circ}C$]) which resticts its practical application. Since this first use of titania, other materials have also been studied with the object of decreasing the temperature dependence whilst retaining favorable dielectric loss, Q, and relative permittivity. The temperature coefficient of temperature compensation capacitor is +100~750[ppm/$^{\circ}C$], dielectric constant 10~150. Low loss ceramics with dielectric constants in the 10~150 range also found application. Recently, their applications are extended in EMI filter and dielectric materials for microwave. There temperature coefficient of dielectric materials approaches 0[ppm/$^{\circ}C$]. The dielectric preperties of zirconia titanate ceramics prepared by addition of $Ta_2O_{5}$ were investigated.

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Microwave Dielectric Properties and Microstructure of $BiNbO_4$ Ceramics ($BiNbO_4$세라믹스의 유전 특성과 미세구조에 관한 연구)

  • 고상기;김현학;김경용
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.3
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    • pp.208-213
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    • 1998
  • Microwave dielectric properties of $BiNbO_4$ containing CuO and $V_2O_5$(BN ceramics). BN ceramic with 0.07wt% $V_2O_5$ and 0.03wt% CuO (BNC3V7) was sintered at $900^{\circ}C$ where it is possible for these to be co-fired with Ag electrode. The dielectric constant of 44.3, TCF (Temperature Coefficient of resonance Frequency) of 2 ppm/$^{\circ}$ and Q${\times}f_o$ value (product of Quality value and resonance Frequency) of 22,000GHz could be obtained from those ceramics. It is observed that orthorhombic structure was stable $1000^{\circ}C$. As sintering temperature increases, the dielectric properties decreased. The main reasons were abnormal grain growth and the main peak of triclinic moved from the main peak of orthorhombic.

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Dielectric properties with variation of doped mount $ZrO_2$ of BSCT ceramics ($ZrO_2$첨가량에 따른 BSCT 세라믹의 유전특성)

  • 조현무;이성갑;이영희;배선기
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2001.07a
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    • pp.153-156
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    • 2001
  • (Ba$_{0.6-x}$Sr$_{0.4}$Ca$_{x}$)TiO$_3$ (x=0.10, 0.15, 0.20) ceramics were fabricated by the mixed-oxide method and their dielectric properties were investigated with variation of composition ratio, doped ZrO$_2$ (0.5, 1.0, 1.5, 2.0, 3.0 wt%) and sintered at 145$0^{\circ}C$. The dielectric constant and loss of the x=0.10 specimen applied field were 19.86 and 0.302 % at 0 V/cm, and 25.937 and 0.339 % at 300 V/cm, respectively. Dielectric constant were increased with increased applied field and decreased with increased frequency, and dielectric loss were within 0.1% at applied 800 MHz, respectively. all specimens showed fairly good applied field. Although, dielectric constant and loss of all specimen showed to tend of nearly the same. same.

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Microwave Dielectric Properties of BZCT Ceramics (BZCT 세라믹의 마이크로파 특성에 관한 연구)

  • 이문기;최의선;류기원;이영희
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.15 no.10
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    • pp.870-875
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    • 2002
  • Ba(Zn$_1$-xCox)TaO$_3$[BZCT] ceramics were Prepared by the conventional mixed oxide method. The ceramics were sintered at the temperature of 1450∼1550$\^{C}$ for 5 hr in air. The crystal structure of BZCT ceramics was investigated by the XRD. The microstructure of the specimens were observed by SEM. The structural properties of BZCT specimens were investigated as a function of composition and sintering temperature. All BZCT ceramics sintered over 1550$\^{C}$ were showed a polycrystalline complek perovskite structure without second phases and any unreacted materials. The density of BZCT (70/30) specimen sintered at 1550$\^{C}$ was 6.31g/㎤. In the case of the BZCT(70/30) ceramics sintered at 1550$\^{C}$ for 5 hours, dielectric constant, qualify factor and temperature coefficient of resonant frequency for microwave dielectrics application were a good value of 29, 16,468 at 10㎓ and -4.4 ppm/$\^{C}$, respectively.

Microwave Dielectric Properties of Sb substituted $BiNbO_4$ Ceramics (Sb 치환에 따른 $BiNbO_4$ 세라믹스의 고주파 유전특성의 변화)

  • Lim, Hyouk;Oh, Young-Jei;Chio, Seo-Young
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2002.07b
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    • pp.646-649
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    • 2002
  • The microwave dielectric properties and the structure of $Sb_2O_5$ modified $BiNb_xSb_{1-x}O_4$ ceramics were investigated. The structure of these ceramics were orthohombic phase at all sintering temperatures and there were not the second phase. These ceramics added sintering additive such as CuO and $V_2O_5$ were sinterable at a low temperature$(880^{\circ}C{\sim}960^{\circ}C)$ by liquid phase. Dielectric properties of $BiNb_xSb_{1-x}O_4$ ceramics were also improved than these of $BiNbO_4$ ceramics. The content of modified atom controlled the microstructure, dielectric constant and quality factor. As a result, We could obtain following result; ${\varepsilon}r$=42~44, $Q{\cdot}f_0$=20,000~42,000GHz, $\tau_f=-7{\sim}-28ppm/^{\circ}C$.

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