• 제목/요약/키워드: $CeO_2$addition

검색결과 182건 처리시간 0.039초

$HfO_2$$CeO_2$가 첨가된 3Y-TZP 치과용 블록의 제조 및 특성 평가 (Preparation and characteristics of $HfO_2$ and $CeO_2$ doped 3Y-TZP block for dental ceramic block)

  • 지상용;지형빈;박홍채;윤석영
    • 한국결정성장학회지
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    • 제19권6호
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    • pp.311-317
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    • 2009
  • CAD/CAM 가공이 가능한 치과용 3Y-TZP블록을 제조하였다. 블록 제조를 위하여 3Y-TZP분말에 $HfO_2$$CeO_2$ 분말을 첨가하여 $800{\sim}1100^{\circ}C$에서 열처리 한 후 $1450^{\circ}C$에서 소결하였으며, 이때 $HfO_2$$CeO_2$ 분말의 첨가량 및 열처리 조건에 따른 블록의 기계적 특성 및 화학적 특성을 조사하였다. EDS mapping 이미지를 통하여 $HfO_2$$CeO_2$ 분말이 3Y-TZP에 비교적 분산이 잘되어 있음을 확인하였다. 본 실험에서는 3 wt% $HfO_2$가 첨가된 블록이 가장 높은 굽힘 강도(1 GPa)를 나타내었으며, 3 wt% $CeO_2$가 첨가된 블록은 수열분위기하에서의 $t-ZrO_2$의 안정성을 향상 시키는 것으로 확인되었다.

Ce0.8Gd0.2O1.9 세라믹스의 소결거동과 전기적 특성에 미치는 Fe2O3의 첨가효과 (Effects of Fe2O3 Additions on Sintering Behavior and Electrical Property of Ce0.8Gd0.2O1.9 Ceramics)

  • 최광훈;이주신;최용규
    • 한국재료학회지
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    • 제17권10호
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    • pp.526-531
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    • 2007
  • The sintering behavior and electrical property of $Ce_{0.8}Gd_{0.2}O_{1.9}$ ceramics were investigated with the iron oxide concentration ranging from 0 to 5 mol%. Both the sintered density and grain size were found to increase up to 2 mol% $Fe_2O_3$, and then to decrease with further additions. At a higher $Fe_2O_3$ content above 3 mol%, grain size decreased by a pinning effect induced by different shape grains. The electrical conductivity was also increased with increasing $Fe_2O_3$ content up to 2 mol%. Total conductivity of 2 mol% $Fe_2O_3-added$ specimen showed the maximum conductivity of $2{\times}10^{-2}{\Omega}{\cdot}cm^{-1}$ at $500^{\circ}C$. The addition of $Fe_2O_3$ was found to promote the sintering properties and electrical conductivities of $Gd_2O_3-dope\;CeO_2$.

액상침투법을 이용한 $Al_2O_3/TZP$ 복합체의 제조 및 특성 (Preparation and Characteristics of $Al_2O_3/TZP$ Composites Using Liquid Infiltration Technique)

  • 양태영;이윤복;김영우;오기동;박홍채
    • 한국재료학회지
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    • 제10권5호
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    • pp.321-327
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    • 2000
  • 다공성 알루미나 소결체내부로 3Y-TZP 및 12Ce-TZP 전구체를 각각 액상침투시킴으로써 2종류의 $Al_2O_3/TZP$복합체를 제조하였다. 소량의 (~11.0 wt%) TZP의 첨가는 Al2O3소결체 ($1600^{\circ}C$, 2시간)의 강도 (19~59%)와 파괴인성(14~157%)을 증가시켰다. 3Y-TZP의 첨가는 복합체의 강도의 향상에 12Ce-TZP의 첨가는 인성의 향상에 보다 효과적이었다. 침투도니 TZP는 복합체의 내부보다 표면에 집중되었으며, 그 결과 이곳에서의 입성장에 빨랐고 $Al_2O_3$의입성장 억제효과도 상대적으로 뛰어났다. 입계 및 입내균열전파가 일어났으나 $Al_2O_3/12Ce-TZP$의 경우가 $Al_2O_3/3Y-TZP$에 비하여 입계파괴가 우세하였다

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Behavior of Oxygen Equilibrium Pressure in CRT Glass Melts doped with Sb and Ce ions from the Viewpoint of Fining

  • Kim, Ki-Dong;Kim, Hyo-Kwang;Kim, Jun-Hong
    • 한국세라믹학회지
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    • 제44권8호
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    • pp.419-423
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    • 2007
  • The behavior of oxygen gas participating in fining was observed in CRT (Cathode Ray Tube) glass melts doped with $Sb_2O_5\;or\;CeO_2$ by means of a yttria-stabilized zirconia (YSZ) electrode. The temperature dependence of the oxygen equilibrium pressure ($P_{o2}$) or the activity in both melts showed typical behavior corresponding to a theoretical redox reaction. In other words, the $P_{o2}$ value of melts with $CeO_2$ was lower than that of melts with $Sb_2O_5$ above $1250^{\circ}C$. The result implies that $Sb_2O_5$, is more efficient as a fining agent compared to $CeO_2$. On the other hand, melts from a batch containing $Sb_2O_5\;and\;KNO_3$ showed much higher $P_{o2}$ values compared to melts without $KNO_3$ above $1350^{\circ}C$. It is suggested that the addition of $KNO_3$ to CRT glass batch contributes partly to the first fining of the melts.

Teflon을 이용한 YAG:Ce 형광체 합성 (Combustion Synthesis of YAG:Ce Phosphor with Teflon)

  • 연정운;원창환;원형일
    • 대한금속재료학회지
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    • 제50권6호
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    • pp.439-443
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    • 2012
  • YAG:Ce phosphor were prepared in a self-propagating high-temperature synthesis (SHS) using a $1.5Y_2O_3+2.5Al_2O_3+0.116CeO_2+3.0KClO_3+kCO(NH_2)_2+m(C_2F_4)_n$ precursor mixture. The heat for the combustion propagation was provided by the reaction of a $KClO_3+CO(NH_2)_2+(C_2F_4)n$ mixture. Pure-phase YAG phosphor was synthesized at the combustion temperature of $1210^{\circ}C$ from k=3.6 mole and m=0.3 mole. The as-prepared YAG:Ce phosphor had a particle size of $2-10{\mu}m$. The addition of Teflon to the precursor mixture increased the YAG particle size and its luminescent intensity. The emission peak of the YAG phosphor was blue-shifted with an increase of Teflon concentration.