• Title/Summary/Keyword: $Ba(Mg_{1/3}Ta_{2/3})O_3$ ceramics

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The Effect of Calcination Temperature on Physical Properties of $Ba[Mg_{1/3}(Nb_{0.2}Ta_{0.8})_{2/3}]O_3$ Ceramics (하소온도가 $Ba[Mg_{1/3}(Nb_{0.2}Ta_{0.8})_{2/3}]O_3$ 세라믹스의 물리적 특성에 미치는 영향)

  • 김재윤;김부근;김강언;정수태;조상희
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1999.11a
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    • pp.252-255
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    • 1999

  • The effect of calcination temperature(1st and 2nd calcining at 110$0^{\circ}C$ , 120$0^{\circ}C$ and 130$0^{\circ}C$ respectively) on physical properties of BMNT Ceramics ware investigated. The optimum 1st and 2nd calcination temperature were 120$0^{\circ}C$ , and sintering temperature was 155$0^{\circ}C$. In this condition, the sintering density was 7.53 [g/㎤] and the dielectric constant, Q.f$_{0}$ and $\tau$$_{r}$ were 26, 80, 300[GHz] and +1.5[ppm/$^{\circ}C$] respectively in the microwave range.e.e.

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A study on Ba$(Mg_{1/3}Ta_{2/3})O_3$ ceramics resonator for Nonradiative Dielectric waveguide (비방사유전체선로에 삽입되는 Ba$(Mg_{1/3}Ta_{2/3})O_3$ 세라믹스 공진기에 관한 연구)

  • Park, Hye-Young;Lee, Ju-Sin
    • Proceedings of the KIEE Conference
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    • 2004.07c
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    • pp.1615-1617
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    • 2004

  • 5 mol% $BaWO_4$를 첨가시켜 합성한 Ba$(Mg_{1/3}Ta_{2/3})O_3$를 이용하여 비방사유전세선로에 삽입되는 세라믹스 공진기를 제자하고 기존의 $MgTiO_3-CaTiO_3$계 세라믹스 공진기와 공진특성을 비교하여 그 특성을 고찰하였다. 그 결과 BMT 세라믹스는 기존의 $MgTiO_3-CaTiO_3$계 세라믹스보다 품질계수가 2배 이상 크게 높게 측정되었고, 측정 사진의 관찰 결과 전파차단성도 우수할 것으로 예상되기 때문에 BMT가 비방사유 전체선로에 삽입되는 유전체 공진기 재료로서 적용될 경우 우수한 공진특성을 발휘할 것으로 판단된다.

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Formation of the Fluorite Structure in the $\textrm{Y}_{0.8}\textrm{Ta}_{0.2}\textrm{O}_{1.7}$-MO(M=Ba, Sr, Ca and Mg) System ($\textrm{Y}_{0.8}\textrm{Ta}_{0.2}\textrm{O}_{1.7}$-MO(M=Ba, Sr, Ca 및 Mg)계에 있어서 형석구조의 생성)

  • Kim, Shin;Choi, Soon-Mok;Lee, Hong-Lim
    • Korean Journal of Materials Research
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    • v.7 no.1
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    • pp.57-61
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    • 1997

  • Formation of fluorite structure and other related crystal structures in the $Y_{0.8}Ta_{0.2}O_{1.7}$-MO(M=Ba, Sr, Ca and Mg) system has been studied $Ba_2YTaO_6,\;Sr_2YTaO_6$ of cubic perovskite type ordered structure anti $Y_2O_3$ of cubic structure were produced besides the defect fluorite structure when 4 moIob of BaO or SrO was added to $Y_{0.8}Ta_{0.2}O_{1.7}$ When CaO more than 8 nlol"/o was added to $Y_{0.8}Ta_{0.2}O_{1.7}$, monoclinic: $Ca_2YTaO$, and cubic $Y_2O_3$ were pri~tlucecl ;IS this sec:onci phases hesides the main fluorite truc,ture. Smglc phase of fluorite structure \vas 1)roduc:ciI when MgO was added up to 12 mol%, however, MgO appeared as the second phase besides the main fluorire structure when MgO was added more than lti moI0'. Consquently, it is considered rh;it the formation of tluorite structure is related with the formation of the cubic perovskite type ordered structure of $A_2(B'B")O_6$ as well as the cation radii of the additives.additives.

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A study on the Microwave Dielectric Properties of Ba(Mg,Co)(Ta,Nb)$O_3$ Ceramics (Ba(Mg,Co)(Ta,Nb)$O_3$ 세라믹의 마이크로파 유전특성에 관한 연구)

  • Lee, Moon-Kee;Chung, Jang-Ho;Bae, Seon-Gi;Lee, Young-Hi
    • Proceedings of the KIEE Conference
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    • 1998.11c
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    • pp.752-754
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    • 1998

  • $Ba(Mg_{(1-x)}Co_x)_{1/3}(Ta_{(1-x)}Nb_x)_{2/3}O_3$ ($x=0.3{\sim}0.6$) ceramics were prepared by the conventional mixed oxide method. The sintering temperature and time were of $1400{\sim}1575[^{\circ}C]$,5[hr.] respectively. The structural and microwave dielectric Properties were investigated with composition ratio and sintering temperature. And then the application for the microwave dielectric resonator was investigated.

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Effect of $B_2O_3$ on the Microstructure and the Microwave Dielectric Properties of the $Ba(Mg_{1/3}Ta_{2/3})O_3$ Ceramics ($Ba(Mg_{1/3}Ta_{2/3})O_3$ 세라믹의 미세구조 및 고주파 유전 특성에 대한 $B_2O_3$의 영향)

  • Kim, Beom-Jong;Kim, Mi-Han;Lee, Woo-Sung;Park, Jong-Chul;Lee, Hwak-Joo;Nahm, Sahn
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.07b
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    • pp.772-775
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    • 2004

  • 본 논문에서는 $B_2O_3$ 첨가가 Ba$(Mg_{1/3}Ta_{2/3})O_3$ (BMT)의 유전특성 및 미세구조의 변화에 미치는 영향에 대해 연구하였다 $B_2O_3$가 소량 첨가되었을 때는 결정립의 성장을 야기하여 치밀한 미세구조를 보였지만, 다량이 첨가된 경우 비정상 결정립 성장을 야기하여 치밀화가 떨어지는 미세구조를 보임과 동시에 $Ba_3Ta_5O_{15}$의 2차상을 형성했다. 이는 소량의 $B_2O_3$ 첨가가 유전특성의 향상을 가져왔지만, 다량의 첨가는 오히려 특성의 악화를 가져온 결과의 원인이라 생각된다. 0.5mol%의 $B_2O_3$를 첨가하여 $1500^{\circ}C$에서 6시간 소결한 경우 ${{\varepsilon}_r}=24$, $Q{\times}f=210,000GHz$의 유전 특성 값과 $4.74ppm/^{\circ}C$의 $T_{cf}$ 값을 얻었다.

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Structure and Dielectric Properties of $(Ba_{1-x}Ca_x)(Mg_{1/3}Ta_{2/3})O_3$ Ceramics ($(Ba_{1-x}Ca_x)(Mg_{1/3}Ta_{2/3})O_3$ 세라믹스의 구조와 유전특성)

  • Cho, Jung-Ho;Cho, Jong-Rae;Kim, Kang-Eun;Chung, Su-Tae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2000.05b
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    • pp.167-170
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    • 2000

  • The structural changes and the dielectric properties of $(Ba_{1-x}Ca_x)(Mg_{1/3}Ta_{2/3})O_3$ (x=0, 0.2, 0.4, 0.6, 0.8, 1) were investigated. The densities of samples were gradually decreased with increasing x, (BMT=7.69, CMT=5.25 $g/cm^3$). The crystal structure of BMT was a untiltied perovskite structure, however BCMT showed antiphase tilting and antiphase-inphase tilting structure. The dielectric constant($\varepsilon_r$) of the highest value was 33 at x=0.2 (BMT=24, CMT=17). The maximum quality factor was 27,500GHz in BMT. The quality factor· of BCMT was decreased to x<0.2 (5,000GHz), and was gradually increased to x>0.2. The temperature coefficients of dielectric constant was positive at x<0.8, and negative in CMT.

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