• 한국재료학회지
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• 제14권6호
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• pp.379-388
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• 2004

To investigate the effect of D-ferrite on the hot workability and surface defect of STS 304 billets containing 3 wt. % Cu, microstructure observations and high temperature mechanical properties test were carried out for the specimens extracted mainly from raw or oxidized billets. It was found that the total $\delta$-ferrite content has little influence on the hot workability, even though the fracture cracks due to high temperature tension or compression test were initiated and propagated mostly along $\delta$/${\gamma}$ boundary in the specimens. On the other hand, it was supposed that the direct causes of surface defects in the wire rolled from the as-continuously cast billet were the grain boundary embrittlement arose from the deep diffusion of oxygen into the grain boundary, and the oxidation of $\delta$-ferrite connected by a grain boundary to the surface during the billet reheating process as well.

• 한국세라믹학회지
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• 제29권5호
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• pp.383-390
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• 1992

We investigated the effect of substrate on the properties of the Ni-Zn-Cu ferrite thin films deposited on SiO2 (1000∼3000${\AA}$) / Si (100) substrate at various conditions by rf magnetron sputtering. A disktype Ni-Zn-Cu ferrite sintered by conventional ceramic process and argon gas were used as a target and a sputtering gas, repectively. The compositions of the thin films measured by EPMA were similar to target composition (Fe: 65.8 at%, Ni: 12.7 at%, Cu: 6.7 at%, Zn: 14.8 at%) irrespective of substrate temperature. Amorphous thin films were deposited when substrate was not intentionally heated, but the films came to crystallize with increasing substrate temperature, and crystalline thin films were deposited at substrate temperature above 200$^{\circ}C$. Below 250$^{\circ}C$ saturation magnetization (Ms), remanence (Mr) and coercivity (Hc) of the ferrite thin film increased with the substrate temperature due to the increase of grain size and the improvement of crystallinity. And above 250$^{\circ}C$, Ms, Mr increased slightly, but Hc of the amorphous thin films increased due to crystallization, whereas that of the crystalline thin films decreased because of grain growth and stress release.

• 한국자기학회지
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• 제15권5호
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• pp.282-286
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• 2005

공침법으로 제조한 Ni-Cu-Zn ferrite를 사용하여 전파흡수체로 사용할 저온소결용 ferrite를 연구하였다. Ni 첨가량에 따른 조성비 및 가소온도와 소결온도 변화를 시켜 전파흡수특성 및 물리적 특성을 고찰하였다. XRD pattern을 통하여 spinel구조를 가짐을 확인하였고, 공침법으로 제조된 Ni-Cu-Zn ferrite 미분말이 나노입자 크기를 보였다 소결온도가 $1100^{\circ}C$이고 Ni 함량이 많을 수록 투자율이 낮고 손실계수도 높게 측정되어 흡수 능력도 좋아짐을 알 수 있고, MHz 영역에서 사용할 수 있다고 사료된다. 그리고 소결온도 $1100^{\circ}C$이고 $(Ni_{0.7}Cu_{0.2}Zn_{0.1}O)_{1.02}(Fe_{2}O_3)_{0.98}$ 조성일 때가 가장 손실이 크므로 전파흡수체로 사용할 조성임을 확인 할 수 있었다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.495-496
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• 2008

The magnetic characteristics of Mg-Zn ferrite that was fired at $1150^{\circ}C$ for 1hour and sintered at $1250^{\circ}C$ for 3hours was examined. The composition ratio of the ferrite was changed after sintering. In that case the composition ratio of ${Fe_2}{O_3}$ was increased but that of CuO was decreased. When the addition quantity of CuO was 3.8 mole%, it's shrinkage rate had maximum value. Magnetic permeability was decreased as the addition rate of CuO was increased and MgO was decreased. When the composition rate of CuO was 2.3 mol% and MgO was 10.9 mol%, the firing density had maximum value. In case that CuO was 2.8mol% and MgO was 10.4mol%, PL had minimum value.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1997년도 춘계연구발표회 논문개요집
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• pp.98-99
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• 1997

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1998년도 춘계연구발표회 논문개요집
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• pp.70-71
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• 1998

• 한국재료학회:학술대회논문집
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• 한국재료학회 1992년도 춘계학술발표회
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• pp.132-133
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• 1992

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1994년도 추계연구발표회 논문개요집
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• pp.72-73
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• 1994

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2003년도 하계학술연구발표회 및 한.일 공동심포지엄
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• pp.190-191
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• 2003

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2000년도 춘계연구발표회 논문개요집
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• pp.38-39
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• 2000