http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
SOFC 음극용 Ni-YSZ 복합체 제조시 생기는 Ni 손실
문환,이종호,이해원,Moon, Hwan,Lee, Jong-Ho,Lee, Hae-Weon 한국세라믹학회 2001 한국세라믹학회지 Vol.38 No.2
SOFC 음극으로 쓰이는 Ni-YSZ 복합체의 제조과정 중에 생기는 조성의 변화를 관찰하였다. XRD를 이용하여 복합체 부위별로 상분석한 결과 Ni-YSZ 복합체는 소결과정이나 환원처리시 복합체 내-외부간의 조성차가 일어나며 이로 인해 전기적 물성의 불균일성이 나타난다. 복합체 조성의 불균일성 및 전기적 물성의 불균일성은 주로 복합체를 구성하는 Ni 성분의 변화에 기인했는데 소결과정이나 환원과정시 Ni 성분이 기판으로 확산해가거나 기상으로 증발해버려 Ni 손실이 생기기 때문인 것으로 나타났다. Ni 성분의 손실은 열처리 온도와 시간에 비례하여 커졌으며 이로 인해 복합체의 전기적 물성도 악화되었다.
박막 테이프캐스팅과 동시소성에 의한 연료극 지지형SOFC 단전지 제조
문환,현상훈,김호성,김선동 한국세라믹학회 2006 한국세라믹학회지 Vol.43 No.12
An anode-supported SOFC single cell having 5 μm thin electrolyte was fabricated cost-effectively by tape casting, laminating, and co-firing of anode (NiO-YSZ), cathode (LSM-YSZ), and electrolyte (YSZ) components. The optimal slurry compositions of the green tapes for SOFC components were determined by an analysis of the mean diameter, the slurry viscosity, the tensile strength/strain of the green tapes, and their green microstructures. The single cells with a dense electrolyte and porous electrodes could be co-fired successfully at 1325~1350o C by controlling the contents of pore former and the ratio of coarse YSZ and fine YSZ in the anode and the cathode. The single cell co-fired at 1350oC showed 100.2 mWcm-2 of maximum power density at 800oC but it was impossible to apply it to operate at low temperature because of low performance and high ASR, which were attributed to formation of the secondary phases in the cathode and the interface between the electrolyte and the cathode.
SOFC 음극용 Ni-YSZ 복합체의 미세구조와 전기적 물성간의 상관관계 : I. 미세구조 분석
문환,이해원,이종호,윤기현,Moon, Hwan,Lee, Hae-Weon,Lee, Jong-Ho,Yoon, Ki-Hyun 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.5
The microstructure of Ni-YSZ composite as an anode of SOFC was investigated as a function of Ni content(10-70 vol%) in order to examine the correlation between microstructural-and electrical property. Image analysis based on quantitative microscopy theory was performed to quantify the microstructural property. We could get the informations about the size and distribution, contiguity and interfacial area of each phase or between the phases from the image analysis. According to the image analysis, contiguity between the same phae was mainly dependent on the amount of the phase while the contiguity between different phases was additionally influenced by the microstructural changes, especailly by the coarsening of the Ni phase. The whole length of pores perimeter was increased as Ni content increased, which indicated the overall microstructural evolution was mostly related with the coarsening of Ni phase. Ni-Ni interfacial area was also gradually increased as Ni content increased but controlled by pore phase at low Ni content region and by YSZ phase at intermediate Ni content region. These quantified microstructural properties were used to characterize the electrical properties of Ni-YSZ composite.
첨가물의 형태가 MLCC X7R 조성의 유전 특성 및 미세구조에 미치는 영향
문환,김민기,전현표,안재평,윤중락,정태석,Moon, Hwan,Kim, Min-Kee,Jeon, Hyun-Pyo,Ahn, Jae-Pyoung,Yoon, Jung-Rag,Chung, Tae-Serk 한국세라믹학회 2003 한국세라믹학회지 Vol.40 No.7
첨가물의 형태가 X7R용 MLCC 유전 원료의 전기적 특성 및 미세구조에 미치는 영향을 평가하였다. Glass frit 및 산화물 형태로 제조된 첨가물을 분말 공정 조건을 달리하여 동일한 주조성에 첨가하였다. 미세구조 및 유전특성을 측정한 결과, glass 층에 dopant의 농도 구배가 존재하는 조성이 유전 특성이 가장 우수하였다. 최적 조성을 MLCC로 제작하여 유전 특성을 측정하였으며, X7R 제반 조건을 만족하였다. Effects of additives on electrical properties and microstructure of MLCC X7R dielectrics have been investigated. The additives of glass frit or oxide form were added in the same main composition by the different powder processing conditions. As a result of the dielectric property and microstructure analysis, the composition having the glass layer with dopant concentration gradient showed the excellent dielectric properties. The MLCCs were fabricated with the excellent composition and all dielectric properties satisfied the X7R requirements.
SOFC 음극용 Ni-YSZ 복합체의 미세구조와 전기적 물성간의 상관관계: II. 경시변화
문환,이해원,이종호,윤기현,Moon, Hwan,Lee, Hae-Weon,Lee, Jong-Ho,Yoon, Ki-Hyun 한국세라믹학회 2000 한국세라믹학회지 Vol.37 No.12
Ni의 함량이 서로 다른 Ni-YSZ 복합체를 100$0^{\circ}C$ 환원 분위기 하에서 열처리하며 시간에 따른 미세구조의 변화를 관찰하였다. Quantitative microscopy 이론을 응용한 화상분석 결과 Ni-YSZ 복합체의 미세구조는 열처리시 나타나는 Ni상의 미세구조 변화에 가장 큰 영향을 받고 있었다. 특히 Ni의 양이 많은 조성에서는 Ni 상간의 접촉이 많아 고상반응에 의한 미세구조의 변화가 심하였는데 이로 인해 복합체 미세구조의 안정화가 느리게 진행되었다. Ni-YSZ 복합체의 전기 전도도 역시 Ni상의 미세구조 변화에 큰 영향을 받았는데 복합체 전체 미세구조의 경시변화와는 달리 Ni상의 많은 조성보다는 Ni상의 percolation이 일어나는 조성 부근에서 더 큰 영향을 받았다. 이로 인해 Ni-YSZ의 전기 전도도는 Ni의 percolation threshold 부근 조성에서 안정화되는데 더 많은 시간을 요하였다.
실험계획법을 적용한 X7R 적층 칩 커패시터의 희토류(Y<sub>2</sub>O<sub>3</sub>, Er<sub>2</sub>O<sub>3</sub>) 첨가에 따른 전기적 특성
윤중락,문환,이헌용,Yoon, Jung-Rag,Moon, Hwan,Lee, Heun-Young 한국전기전자재료학회 2010 전기전자재료학회논문지 Vol.23 No.3
Employing statistical design of experiments, the difference in doping behaviors of rare-earth ions and their effects on the dielectric property and microstructure of $BaTiO_3$-MgO-$MnO_2$-($Ba_{0.4}Ca_{0.6}$) $SiO_3-Re_2O_3$ (Re = $Y_2O_3$, $Er_2O_3$) system were investigated. Through the statistical analysis we have found that the amount of $Re_2O_3$ are significantly affecting on the dielectric properties. The $Re_2O_3$ improved the dielectric constant, dielectric loss and R*C constant, so the appropriate contents of $Y_2O_3$ and $Er_2O_3$ were 0.8 ~ 1.2 mol% and 0.8 ~ 1.3 mol%, respectively. The MLCC(mutilayer chip capacitor) with $2.0{\times}1.2{\times}1.2mm$ size and 475 nF was also suited for X7R with the above composition. It showed that the dielectric constant and RC constant were 2,839 and 3,675 ${\Omega}F$, respectively in the sintering condition at $1250^{\circ}C$ in $Po_2$ $10^{-7}$ Mpa.
박언우,문환,이종진,현상훈 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.12
The Cu-Ni-YSZ cermet anodes for direct use of methane in solid oxide fuel cells have been fabricated by electroplating Cu into the porous Ni-YSZ cermet anode. The uniform distribution of Cu in the Ni-YSZ anode could be obtained via pulse electroplating in the aqueous solution mixture of CuSO4 ·5H2O and H2SO4 for 30 min with 0.05 A of average applied current. The power density (0.17 Wcm−2 ) of a single cell with a Cu-Ni-YSZ anode was shown to be slightly lower in methane at 700 o C, compared with the power density (0.28Wcm−2 ) of a single cell with a Ni-YSZ anode. However, the performance of the Ni-YSZ anode-supported single cell was abruptly degraded over 21 h because of carbon deposition, whereas the Cu-Ni-YSZ anode-supported single cell showed the enhanced durability upto 52 h. The Cu-Ni-YSZ cermet anodes for direct use of methane in solid oxide fuel cells have been fabricated by electroplating Cu into the porous Ni-YSZ cermet anode. The uniform distribution of Cu in the Ni-YSZ anode could be obtained via pulse electroplating in the aqueous solution mixture of CuSO4 ·5H2O and H2SO4 for 30 min with 0.05 A of average applied current. The power density (0.17 Wcm−2 ) of a single cell with a Cu-Ni-YSZ anode was shown to be slightly lower in methane at 700 o C, compared with the power density (0.28Wcm−2 ) of a single cell with a Ni-YSZ anode. However, the performance of the Ni-YSZ anode-supported single cell was abruptly degraded over 21 h because of carbon deposition, whereas the Cu-Ni-YSZ anode-supported single cell showed the enhanced durability upto 52 h.