http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
$Al_2$$O_3$/$ZrO_2$적층복합체의 균열생성 및 전파거동
방희곤,박상엽 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.11
연속슬립캐스팅 및 상압소결법으로 $Al_2$O$_3$/ZrO$_2$적층복합체를 제조하였으며, 적층복합체에서 ZrO$_2$층을 단사정, 정방정 및 입방정으로 각각 달리 적층하여 균열생성 및 전파 거동에 미치는 ZrO$_2$상의 영향을 고찰하였다. 균열 생성은 냉각시 $Al_2$O$_3$층과 ZrO$_2$층 간의 열팽창 계수의 차이에 의한 열적불일치응력이 가장 큰 요인으로 작용하였다. 적층체 내에 존재하는 균열은 tetra-ZrO$_2$의 경우 적층두께 조절로 가능하였으며, cubic-ZrO$_2$의 경우는 냉각속도 조절로 균열밀도로 크게 낮출 수 있었다. $Al_2$O$_3$/ZrO$_2$적층체를 구성하는 세가지 ZrO$_2$상(mono, tetra, cubic)들 중에서 cubic-ZrO$_2$가 포함된 적층체의 경우 $Al_2$O$_3$와 ZrO$_2$계면에 형성된 잔류압축응력으로 인한 균열굴절 효과를 얻을 수 있었다.
플라이 애쉬를 이용한 코디어라이트 세라믹 하니컴 필터 제조 및 물성
김성진,방희곤,박상엽,Kim, Sung-Jin,Bang, Hee-Gon,Park, Sang-Yeup 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.6
The fabrication process of the honeycomb filter was investigated using synthesized cordierite with the addition of pore former and extrusion additives (either organic matter or graphite). Also, the effect of additives on the resultant properties of honeycomb filter such as porosity, thermal expansion coefficient and mechanical strength were investigated. With increasing the organic matter up to 10 wt%, porosity was increased but compressive strength was decreased. With increasing the graphite content, however, both porosity and compressive strength were increased. The specimen with an optimum processing condition (C-17A30G, sintering at $1150^{\circ}C$) was demonstrated 59% in porosity, 69 MPa in compressive strength, and $2.4{\times}10^{-6}/^{\circ}C\;(25{\sim}1000^{\circ}C$) in thermal expansion coefficient, which physical properties are appropriate for the honeycomb filter applications.
김성환,방희곤,박상엽,Kim, Sung-Hwan,Bang, Hee-Gon,Park, Sang-Yeup 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.11
In this study, we attempted to recycle the fly ash as a mullite whisker with addition of $Al_{2}O_{3}$ to obtain the high yield of mullite whisker. During the reaction process, mullite whisker was formed with the reaction of amorphous $\alpha$-Cristobalite and Anorthite above $1350^{\circ}C$. With increasing the heat treatment temperature and time, the mean length and aspect ratio of mullite whiskers was gradually increased.
플라이 애쉬를 이용한 다공성 코디어라이트의 합성 및 특성
김성진,방희곤,박상엽,Kim, Sung-Jin,Bang, Hee-Gon,Park, Sang-Yeup 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.6
Porous cordierite was synthesized by the mechano-chemical processing using fly ash. The phase evolution of cordierite was investigated as a function of processing variables such as milling time and sintering temperature. In this study, the phase transition path of cordierite from fly ash was followed by sapprine/spinel ${\to}$ mullite/spinel ${\to}{\alpha}$-cordierite. Porous cordierite fabricated after 32 h of milling time and sintering at $1150^{\circ}C$ showed relatively low thermal expansion coefficient ($2.5{\times}10^{-6}/^{\circ}C\;(25{\sim}1000^{\circ}C$)) and high porosity (75%).
김성환,방희곤,박상엽 한국세라믹학회 2005 한국세라믹학회지 Vol.42 No.11
In this study, we attempted to recycle the fly ash as a mullite whisker with addition of Al2O3 to obtain the high yield of mullite whisker. During the reaction process, mullite whisker was formed with the reaction of amorphous α-Cristobalite and Anorthite above 1350oC. With increasing the heat treatment temperature and time, the mean length and aspect ratio of mullite whiskers was gradually increased.
수산화아파타이트/알루미나 복합체의 기계적 특성에 미치는 불화물 첨가제의 영향
김성환,방희곤,박상엽,Kim, Sung-Hwan,Bang, Hee-Gon,Park, Sang-Yeup 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.1
Hydroxyapatite $(HAp,\;Ca_{10}(PO_4)_6(OH)_2)$/alumina composites were fabricated with the addition of fluorides, such as $MgF_2$ and $CaF_2$. In this study, the effect of fluorides on the inhibition of phase decomposition and the mechanical properties of HAp was investigated. Due to the higher solubility of F ion in HAp structure, $MgF_2$ additive was more effective compared to $CaF_2$ additive in the lowering decomposition temperature of HAp. Therefore, the dissociation tendency of HAp was fully inhibited below $1400^{\circ}C$. The mechanical properties of HAp composites with $MgF_2$ additive showed higher value (flexural strength: $\~170MPa$, Vickers hardness: $\~7\;GPa$, fracture toughness: $\~1.5\;MPam^{1/2}$) compared to $MgF_2-free$ composites. The linear thermal expansion coefficient of HAp composites with $MgF_2$ showed the value of $16.4\times10^{-6}/^{\circ}C\;at\;20\~400^{\circ}C $.