• Proceedings of the Korean Ceranic Society Conference
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• 2002.10a
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• pp.153.2-153
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• 2002

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.154.2-154
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• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.207.1-207
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• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.207.2-207
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.71.2-71
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• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
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• pp.82.1-82
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• 2003

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1990.11a
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• pp.36-40
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• 1990

세라믹재료는 ductility가 작아 그 강도가 균열의 가혹성, 즉 크기와 모양에 의하여 결정되는 특징을 가지고 있다. 한편 마모는 표면에 균열을 생성시킬 수 있기 때문에 강도에 큰 영향을 미칠 수 있다. 그러나 지금까지 강도에 미치는 마모의 영향은 잘 밝혀져 있지 않다. 따라서 본 연구에서는 세라믹재료중에서도 물리적 성질들이 잘 알려져 있는 알루미나를 택하여 마모기구를 관찰하고 마모가 강도에 미치는 영향을 관찰하였다. 소결후 고온등방가압 처리된 알루미나 소결체를 입수하여 3mmX4mmX40mm크기의 굽힘시험시편으로 가공하였다. 두개의 4mmX40mm면중에서 한명을 diamond paste $1\mu m$까지 사용하여 polishing하였다. 시편의 polishing된 면위에 질화규소 볼을 올려 놓고, 하중을 가한 상태에서 볼을 와복운동시켰다. 시편위에 형성되는 마모흔적의 길이를 16mm이상이 되도록 하였다. 왕복속도는 약 2 헤르쯔도 하였다. 하중은 300, 600, 900N으로 하였다. 윤활유로는 paraffin oil을 사용하였다. 마모시험이 끝난 시편을 광학현미경 및 주사전자현미경으로 관찰한 후, 4-점굽힘시험하여 강도를 구하였다. 4-점굽힘시험시 외부 및 내부 지지점간의 거리는 30mm, 10mm로 하였으며, cross head speed는 분당 0.5mm로 하였다.

• Journal of the Korean Ceramic Society
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• v.38 no.2
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• pp.238-238
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• 2001

15% Syn M, sintered mullite(SM) and fused mullite(FM) was added to produce high alumina refractory materials. Mullite content of SM, FM and Syn M was 93.17%, 86.79%, 97.57% repectively. Mechanical properties of specimens (added 15wt% mullite) ware investigated to be flexural strength 338.60MPa, compressive stcngth 9,427kgf/㎠. But the specimen which imported mullite was added showed 5~10%l lower stregth than syn M added.

• Journal of the Korean Ceramic Society
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• v.41 no.12 s.271
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• pp.939-945
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• 2004

Glasses of $SiO_2-B_{2}O_3-Al_{2}O_3-CaO-La_{2}O_3$ with various amounts of $La_{2}O_3$ were infiltrated into a porous alumina to make an alumina-glass composite. The infiltration characterization and bending strength of the composite were examined in terms of glass composition. $La_{2}O_3$ in the glass decreased the high temperature viscosity and this enhanced the wetting behaviour of this glass to alumina, and made glass infiltration easier. The infiltrated glass dissolved the alumina skeleton, and $Al_{2}O_3$ component in the glass melt reprecipitated on the alumina. The grain growth occurred to a specific crystal direction. The glass containing $20mole\%$ of $La_{2}O_3$ was crystallized after infiltration, and this enhanced the bending strength of the composite.

• Composites Research
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• v.18 no.6
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• pp.40-47
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• 2005

In this study, we tried to invent ceramic armor material with brilliant ballistic properties by the silica of the high compression-expansion ratio and based on alumina that has the most economical and higher ballistic efficiency. After we choose three compositions, proper sintering temperature for each composition was decided. After physical/mechanical measurement, we measured ballistic properties about KE(Kinetic Energy, L/D=10.7, tungsten heavy alloy) and HEAT(High Explosive Anti-Tank, K215) projectiles. As a result, $46\%\;Al_2O_3\;-\;51\%\;SiO_2$ of three compositions had the highest ballistic efficiency md better properties than alumina.