V₂O₅ 도핑된 NiCuZn 페라이트로 제조된 칩인덕터에서의 Ag/cu 석출

제해준,김병국,Je, Hae-June,Kim, Byung-Kook 한국재료학회 2003 한국재료학회지 Vol.13 No.8

The purpose of this study is to investigate the effect of $V_2$$O_{5}$ addition on the Ag and Cu precipitation in the NiCuZn ferrite layers of 7.7${\times}$4.5${\times}$1.0 mm sized multi-layer chip inductors prepared by the screen printing method using 0∼0.5 wt% $V_2$$O_{5}$ -doped ferrite pastes. With increasing the $V_2$$O_{5}$ content and sintering temperature, Ag and Cu oxide coprecipitated more and more at the polished surface of ferrite layers during re-annealing at $840^{\circ}C$. It was thought that during the sintering process, V dissolved in the NiCuZn ferrite lattice and the Ag-Cu liquid phase of low melting point was formed in the ferrite layers due to the Cu segregation from the ferrite lattice and Ag diffusion from the internal electrode. During re-annealing at $840^{\circ}C$, the Ag-Cu liquid phase came out the polished surface of ferrite layers, and was decomposed into the isolated Ag particles and the Cu oxide phase during the cooling process.

$V_2O_5$ 도핑한 페라이트 페이스트 후막 특성

제해준,김병국,박재환,박재관 한국결정학회 2001 韓國結晶學會誌 Vol.12 No.2

NiCuZn 페라이트에 V₂O/sub 5/가 0∼0.5 wt% 첨가된 페이스트를 사용하여 스크린 인쇄법으로 페라이트 후막을 제조한 후, 870∼900℃에서 소결하여 V₂O/sub 5/ 첨가량에 따른 소결밀도, 미세구조 등의 물리적 특성 및 자기적 특성 변화를 분석하였다. 소결온도 870℃의 경우 V₂O/sub 5/를 0.5 wt% 첨가한 시편의 소결밀도가 0.58 g/cm³로 가장 hsvrp 나타낫고, 소결온도가 올라갈수록 소결밀도 차이가 줄어들어 900℃의 경우 모든 시편이 5.15g/cm³이상으로 높은 밀도를 나타내었다. V₂O/sub 5/가 0.5 wt% 첨가된 경우에 액상소결이 발달하였으며, V₂O/sub 5/가 0.1, 0.3 wt% 첨가된 시편은 입자성장이 억제되어 입자크기가 V₂O/sub 5/를 첨가하지 않은 시편보다 작았다. 전체의 소결온도 범위에서 V₂O/sub 5/가 첨가되지 않은 시편의 입자크기가 크고 균일하기 때문에 투자율이 가장 높게 나타났으며, 소결온도 880℃ 이상에서 V₂O/sub 5/ 0.3 wt% 첨가 시편의 Q값이 가장 높은 것으로 나타났다. 결론적으로 칩 인덕터용 NiCuZn 페라이트 소재 제조 시, 투자율값을 중시할 경우에는 V₂O/sub 5/를 첨가하지 않아야 하며, 품질계수를 중시할 경우에는 V₂O/sub 5/의 첨가량이 0.3wt%를 넘지 않아야 함을 알 수 있었다. The purpose of this study is to investigate the effect of V₂O/sub 5/ addition on physical and magnetic properties of NiCuZn ferrite for multi-layer chip inductors. NiCuZn ferrite pastes doped with 0, 0.1, 0.3 and 0.5 wt% V₂O/sub 5/ were prepared and samples of ferrite sheets were prepared by the screen printing method. They were sintered at 870, 880, 890 and 900℃, and then their physical and magnetic properties were analyzed. After sintering at 870℃, the sintered density of the ferrite sheet doped with 0.5wt% V₂O/sub 5/ showed the highest value to 5.08g/cm³due to the best densification by the liquid phase sintering, while the microstructures of ferrite sheets doped with 0.1 and 0.3 wt% V₂O/sub 5/ showed and inhibited grain growth. Irrespective of the sintering temperature, the initial permeability of ferrite sheet doped with 0.5 wt% V₂O/sub 5/ was highest and after sintering beyond 880℃, the quality factor of 0.3 wt% V₂O/sub 5/-doped sample appeared to be highest.

페라이트 후막 제조기술

제해준 한국세라믹학회 1999 세라미스트 Vol.2 No.4

접합유리와 반응된 Fe-Hf-N/Cr/SiO₂ 박막의 연자기 특성 열화

제해준,김병국,Je Hae-June,Kim Byung-Kook 한국재료학회 2004 한국재료학회지 Vol.14 No.11

The degradation mechanism of soft magnetic properties of $Fe-Hf-N/Cr/SiO_2$ thin films reacted with a bonding glass was investigated. When $Fe-Hf-N/Cr/SiO_2$ films were annealed under $600^{\circ}C$ without the bonding glass, the compositions and the soft magnetic properties of Fe-Hf-N layers were not changed. However, after reaction with the bonding glass at $550^{\circ}C$, the soft magnetic properties of the film were degraded. At $600^{\circ}C$, the saturation magnetization of the reacted film decreased to 13.5 kG, and its coercivity increased to 4 Oe, and its effective permeability decreased to 700. It was founded that O diffused from the glass into the Fe-Hf-N layers during the reaction and generated $HfO_2$ phases. It was considered that the soft magnetic properties of the $Fe-Hf-N/Cr/SiO_2$ films reacted with the bonding glass were primarily degraded by the formation of the Fe-Hf-O-N layer of which the Fe content was below 60 $at\%$, and secondarily degraded by the Fe-Hf-O-N layer above 70 $at\%$.

$Fe_2O_3$ 미량 변화에 따른 Mn-Zn 페라이트 단결정의 전자기적 특성

제해준,변순천,홍국선,장성도 한국세라믹학회 1993 한국세라믹학회지 Vol.30 No.10

The electro-magnetic properties of the Mn-Zn ferrite single crystal with small variation of Fe2O3 concentration at the high permeability composition, 53mol% Fe2O3-28.5mol% MnO-18.5mol% ZnO, have been studied for the VCR magnetic head application. With the increase of the Fe2O3 concentration, the Fe2+ concentration increased, the specific resistivity decreased, the secondary maximum permeability shifted to the lower temperature, and the initial permeability decreased. It was concluded that the small variation of $\pm$0.5mol% Fe2O3 concentration greatly affected the electro-magnetic properties of Mn-Zn ferrite single crystals. At the composition of 53mol% Fe2O3, the initial permeability was comparatively high (650 at 5MHz) and its temperature dependence was small.

페라이트와 유리의 접합계면반응의 자기적 특성

제해준,박병원,홍성현,홍국선 한국세라믹학회 1993 한국세라믹학회지 Vol.30 No.5

Chemical reaction occurred in the interface of Mn-Zn ferrite and glass after bonding. Effects of the formation of reaction layer on the magnetic properties were investigated. The composition of glass was 23PbO-61SiO2-6ZnO-8Na2O-2K2O and the ferrite was chosen to have a high permeability. Toroid samples of ferrites bonded with glasses, were heat-treated at $700^{\circ}C$, 80$0^{\circ}C$ and 90$0^{\circ}C$ for 1h. The reaction was observed to increase with bonding temperature, resulting in the development of reaction layer. Subsequently the initial permeability was found to be decreased. The permeabilities decreased by 25% with increasing bonding temperature from $700^{\circ}C$ to 80$0^{\circ}C$. At the bonding temperature of 90$0^{\circ}C$, the permeability was decreased by 45%, compared to that of 80$0^{\circ}C$.

Fe-Hf-N 박막의 열처리 후 연차기특성 열화

제해준,박재환,김영환,김병국 한국결정학회 2001 韓國結晶學會誌 Vol.12 No.3

고포화자속밀도 특성을 갖는 Fe-Hf-N 박막의 진공분위기 열처리 시 발생하는 연자기 특성 열화현상을 조사하였다. 열처리 온도는 450℃∼650℃이며, TEM 분석 및 전자회절빔 분석을 통하여 박막의 미세구조와 국부적 미세결정상을분석하였다 450℃에서 600℃까지 열처리한 박막의 연자기 특성은 미세화 되어있는 α-Fe 결정립이 성장함에 따라, 열처리 전에 비해 보자력 이 0.2 Oe 정도 증가하고 유효투자율이 1500 정도 감소하는 것으로 나타났다. 포화자속밀도는 600℃ 이하까지는 0.5 KG 정도 미량 증가하나 650℃에서는 모든 연자기 특성 이 급격하게 떨어졌다. 이러한 열화현상은 650℃ 열처리시 α-Fe격자 내에 존재하던 N이 HfN로 석출됨에 따라, α-Fe 결정립이 급격히 성장하여 박막의 미세구조가 초미세 결정구조를 벗어났기 때문인 것으로 나타났다. The purpose of this study is to investigate the degradation of soft magnetic properties of Fe-Hf-N thin films after annealing in vacuum. They were annealed at 450℃∼650℃. The microstructure and crystal phase of the selected area of the thin films were analyzed by TEM and SAD. After annealing at 450℃-600℃, the coercivity of the films increased by 0.2 Oe and the effective permeability decreased by 1500 as compared with them before annealing due to the growth of α-Fe crystallites. The saturation magnetic flux density of the films increased by 0.5 KG after annealing under 600℃. However, the soft magnetic properties of the film annealed at 650℃ degraded abruptly, which was attributed to the destruction of nano-crystalline microstructure of the film due to the rapid growth of α-Fe crystallites with the segregation of N sited in the α-Fe lattice into HfN.

[재료]상평형도를 이용한 Mn-Zn 페라이트 단결정 조성 조절

제해준(Hee-June Je),김인태(In-Tae Kim),홍국선(Kug-Sun Hong) 한국분석과학회 1992 분석과학 Vol.5 No.3

Mn - Zn 페라이트 단결정과 접합유리와의 계면반응이 자기적특성에 미치는 영향

제해준(Hae June Je),김영환(Young Hwan Kim),김병국(Byung Kook Kim),박재관(Jae Gwan Park) 한국자기학회 2001 韓國磁氣學會誌 Vol.11 No.5

The effect of interface reaction between Mn-Zn ferrite single crystal and 61SiO₂-23PbO-6ZnO-8Na₂0-2K₂0 (㏖%) glass on the magnetic properties of the ferrite was investigated. After the reaction, the hump of Zn concentration appeared at the ferrite adjacent to the interface. The initial permeability of the ferrite bonded with the glass at 700℃ was 1766 at 100 KHz and reduced to 907 after reaction at 1000 ℃. The permeability degradation with increasing reaction temperature was considered to be attributed not only to the size diminution of the ferrite due to the its dissolution into the glass but also to the residual stress due to the difference in expansion coefficient between the ferrite and the diffusion layer-the region of the hump of Zn concentration-adjacent to the interface.

V₂O5 도핑한 페라이트 페이스트로 제조된 칩인덕터의 자기적 특성

제해준(Hae June Je) 한국자기학회 2003 韓國磁氣學會誌 Vol.13 No.3

The purpose of this study is to investigate the effect of V₂O_5 addition on the microstructures and magnetic properties of 7.7×4.5×1.0 ㎜ sized multi-layer chip inductors prepared by the screen printing method using 0~0.5 wt% V₂O_5-doped NiCuZn ferrite pastes. With increasing the V₂O_5 content, the exaggerated grain growth of ferrite layers was developed due to the promotion of Ag diffusion and Cu segregation into the grain boundaries of ferrites, which affected significantly the magnetic properties of the chip inductors. After sintering at 900oC, the inductance at 10 MHz of the 0.5 wt% V₂O_5-doped chip inductor was 3.7 ?H less than 4.2 ?H of the 0.3 wt% V₂O_5-doped one, which was thought to be caused by the residual stress at the ferrite layers increased with the promotion of Ag diffusion and Cu segregation. The quality factor of the 0.5 wt% V₂O_5-doped chip inductor decreased with increasing the sintering temperature, which was considered to be caused by the electrical resistivity of the ferrite layer decreased with the promotion of Ag/Cu segregation at the grain boundaries and the growth of the mean grain size of ferrite due to exaggerated grain growth of ferrite layers.