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CeO<sub>2</sub>의 첨가량 변화에 따른 세리아 안정화 지르코니아 세라믹스의 기계적 특성 관찰
강종봉,Kang, Jong-Bong 한국세라믹학회 2010 한국세라믹학회지 Vol.47 No.5
The usual ceramic process of mixing and milling in state of oxide of $ZrO_2$ and $CeO_2$ was adopted in wet process to manufacture Ce-TZP in this study. The maximum dispersion point of every slurry manufactured with mixture of $ZrO_2$ and $CeO_2$ was neat at pH10. The stable slurry in average particle size of 90 nm can be manufactured when it is dispersed with use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with addition of $CeO_2$ less than 10 mol% was progressed to the fracture of specimen due to the monoclinic phase existence more than 30% at the room temperature. More than 99% of tetragonal phase was created for the sintered body with addition of $CeO_2$ beyond 18 mol%, but the mechanical property degrade on the entire specimen was brought due to the $CeO_2$ existing above 3%. Consequently, the optimal Ce-TZP combined in oxide state was identified in 16 mol% of $CeO_2$ contents.
Y2O3와 CeO2의 첨가에 따른 Y-TZP계 세라믹스의 기계적 특성
강종봉 ( Jong Bong Kang ),정승화 ( Seung Hwa Jung ),문종수 ( Jong Soo Mun ),정기욱 ( Ki Uk Jung ) 경남대학교 신소재연구소 2009 신소재연구 Vol.21 No.-
Y-TZP계 세라믹스의 특성 및 기계적 물성을 향상시키기 위한 대표적인 첨가제로는 SiO2, TiO2, Fe2O3, Al2O3 등을 들 수 있으며, 이러한 첨가제들의 종류와 양은 Y-TZP계 세라믹스의 기계적 물성에 있어서 제조 공정 조정 변수와 더불어 중요한 역할을 한다. 본 실험에서는 Y2O3와 CeO2의 첨가가 Y-TZP세라믹스에 미치는 영향을 확인하기 위하여, 지르코니아에 안정화제인 Y2O3를 2.4~3.4 mol% 첨가하여 혼합 밀링 하였으며, CeO2의 첨가로 인한 3.2Y-TZP의 소결체에 미치는 영향에 대하여 연구하였다. 그 결과 Y2O3가 3.2 mol% 첨가된 3.2Y 시편은 1400℃에서 6.08 g/cm3의 겉보기 밀도와 1390.4 Hv의 높은 경도 값을 나타내었으며, 1300℃에서부터 정방정상으로의 상전이가 이루어졌다. 하지만 1500℃ 온도구간에서 다시 단사정상이 잔존해있음을 관찰하였다. Y2O3가 3.2 mol% 첨가된 3.2Y 시편에 CeO2를 0.l wt% 첨가 시 1350℃에서 가장 높은 1404.4 Hv의 경도와, 6.08 g/cm3의 겉보기 밀도 값을 가졌지만 1500℃에서 단사정상이 잔존해있음을 관찰하였으며, 미세구조 관찰 시 CeO2의 첨가량이 증가할수록 큰 결정립들이 관찰되었고, 이러한 결정립들이 정방정상의 임계크기 이상으로 성장하였기 때문에 단사정상이 잔존해 있는 것으로 사료되어진다. Zirconia ceramics is the excellent mechanical properties of the organic phase-moss. Because zirconia ceramics trans from tetragonal to monoclinic. This is used structural materials. The Y-TZP of ceramics are the most widely used. Typically, 3Y-TZP powder made coprecipitation is the high cost of manufacturing and highly sintering temperature than 1450℃. In this study, Powder mixed and milled of the Y2O3 and ZrO2 oxides will decrease costs. It is purpose to lowering sintering temperature and increasing mechanical properties by added Al2O3 and CeO2. 3.2Y-TZP added 0.25 wt% of Al2O3 got 99.4% of theoretical density value by 1350℃ sintered. 32Y-TZP added 0.25 wt% Al2O3 and 0.1 wt% CeO2 got the best hardness (1412.1 Hv) by 1400℃ sintered.
Al(OH)<sub>3</sub>-SiO<sub>2</sub>-AlF<sub>3</sub> 조성으로 합성된 뮬라이트 휘스커의 특성평가
이홍림,강종봉,Lee, Hong-Lim,Kang, Jong-Bong 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.5
Mullite whiskers were synthesized by a vapor-solid reaction with $Al(OH)_3-SiO_2-AlF_3$. The heat treatment temperature did not affect the shape of mullite whisker but the composition change resulted in different sizes. The first one was $30-50{\mu}m$ in size with the aspect ratio of 60 and above, and the second one was $600{\mu}m$ and below in size with the aspect ratio of 15 and below. The $Al_2O_3$ content in formed mullite whisker was 73.57-80.29 wt%, which is high $Al_2O_3$ content composition. The Young's modulus and the hardness measured by nano-indentation method were 136.7 GPa and 19.81 GPa, respectively.
수성 현탁액에서 카르복실기를 포함하는 혼합 분산제에 의한 이트리아 안정화 지르코니아의 분산성 향상
김수현,강종봉,배성환,Kim, Soo-Hyun,Kang, Jong-Bong,Bae, Sung-Hwan 한국재료학회 2018 한국재료학회지 Vol.28 No.2
Stable slurries of YSZ in aqueous suspension with added polymer dispersants, namely, poly-methacrylic acid ammonium salt (PMMA), poly-acrylic acid (PAA) and poly-acrylic-co-maleic acid (PAMA), were mixed with the monomolecular dispersants citric acid and oxalic acid. The dispersion properties of the suspension were investigated using PSA, viscosity, sedimentation, and FT-IR. The polymer dispersants and monomolecular dispersants were attached to the YSZ surface by the carboxylic group, as shown by the FTIR results. A stabilized aqueous suspension was obtained when the polymer dispersant and citric acid were mixed and compared to the use of citric acid alone as a dispersant agent. When the polymer dispersant and citric acid were mixed and milled through attrition milling, there was a smaller particle size compared to when the polymer dispersant alone was used as a dispersant agent. This study determined that the particle size of the mixed dispersant was affected by the properties of the monomolecular dispersant and that the stability of the suspension was affected by the polymer dispersant. However, when slurries of YSZ were mixed with oxalic acid, the particle bridging behavior was the result of the high degree of viscosity and the small sedimentation height.
이근봉,강종봉,Lee, Keun-Bong,Kang, Jong-Bong 한국재료학회 2008 한국재료학회지 Vol.18 No.11
The sintering behavior of zircon with silica was investigated. Zircon with 5 vol% of sedimentation $SiO_2$ resulted in the apparent density of $4.45\;g/cm^3$, the diametral tensile strength of $12.125\;kgf/cm^2$, and the micro Vickers hardness of 1283 HV. The dissociation temperature and mechanical characteristics of the $ZrSiO_4$ were changed with different kinds of $SiO_2$. $SiO_2$ addition prevented dissociation of $ZrSiO_4$. Zircon with 5 vol% of sedimentation $SiO_2$ and with 5 vol% of fused $SiO_2$ resulted in increased diametral tensile strength and increased micro Vickers hardness by suppression of $ZrSiO_4$ dissociation and low temperature liquid $SiO_2$ formation. Zircon with fumed $SiO_2$ and quartz $SiO_2$ resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of cristobalite and quartz phase formation and high temperature liquid $SiO_2$ formation. Zircon with 10 vol% of $SiO_2$ resulted in decreased diametral tensile strength and decreased micro Vickers hardness because of weak particle coupling due to excess formation of liquid $SiO_2$.
세리아 안정화 지르코니아의 제조 및 특성(I) : CeO<sub>2</sub>첨가량 변화에 따른 Ce-TZP의 기계적 특성
정승화,강종봉,Jung, Seung-Hwa,Kang, Jong-Bong 한국재료학회 2010 한국재료학회지 Vol.20 No.7
The usual ceramic process of mixing and milling in state of oxides $ZrO_2$ and $CeO_2$ was adopted in this study in a wet process to manufacture Ce-TZP. $CeO_2$-$ZrO_2$ ceramics containing 8~20 mol% $CeO_2$ were made by heat treatment at $1250\sim1500^{\circ}C$ for 5hr. The maximum dispersion point of every slurry manufactured with a mixture of $ZrO_2$ and $CeO_2$ was neat at pH10. A stable slurry with average particle size of 90 nm can be manufactured when it is dispersed with the use of ammonia water and polycarboxylic acid ammonium. The sintered Ce-TZP ceramics manufactured with the addition of $CeO_2$ in a concentration of less than 10 mol% progressed to the fracture of the specimen due to the existence of a monoclinic phase of more than 30% at room temperature. More than 99% of the tetragonal phase was created for the sintered body with the addition of $CeO_2$ beyond 18 mol%, but the degradation of the mechanical properties on the entire specimen was brought about due to the $CeO_2$ existing in a percentage above 3%. Consequently, the optimal Ce-TZP level combined in the oxide state was identified to be 16 mol% of $CeO_2$ contents.