• 반도체디스플레이기술학회지
• /
• 제6권3호
• /
• pp.13-17
• /
• 2007

Effect of Co substitution on crystal structures of two nickel silicides, NiSi and $NiSi_2$, is investigated by using an ab initio calculation. Relaxed NiSi and $NiSi_2$ structures are calculated and the calculated lattice parameters are in good agreement with experimentally determined lattice parameters within about 2%. A Co atom substitutes a Ni and Si site, respectively, to evaluate the preferable site between them. Co prefers Ni site to Si site in both NiSi and $NiSi_2$. The calculated total energy also indicates that the Co substitution to Ni site stabilizes both the NiSi and $NiSi_2$ structures. Co also prefers Ni site in $NiSi_2$ to that in NiSi, indicating that $NiSi_2$ becomes more stable than NiSi with Co substitution. As Co addition to NiSi improves its thermal stability experimentally, this indicates that the energy barrier between the two phases is high enough to prevent the phase transformation from NiSi to $NiSi_2$ up to high temperature.

• 열처리공학회지
• /
• 제9권2호
• /
• pp.79-90
• /
• 1996

Transmission electron microscopy(TEM) investigation on the phase decomposition of B2-ordered (Ni,Co)Al supersaturated with Ni and Co has revealed the precipitation of $(Ni,Co)_2Al$ which has not been expected from the reported equilibrium phase diagram. The $(Ni,Co)_2Al$ phase has a hexagonal struture and takes a rod-like shape with the long axis of the rod parallel to the <111> directions of the B2 matrix. By aging at temperatures below 873 K, a long period Superlattice Structure appears in the hexagonal $(Ni,Co)_2Al$ Phase. The orientation relationship between the $(Ni,Co)_2Al$ Precipitates and the B2-(Ni,Co)Al matrix is found to be$(0001)_p$ // $(111)_{B2}$ and $[\bar{1}2\bar{1}0]_P$ // $[\bar{1}10]_{B2}$, Where the suffix p and B2 denote the $(Ni,Co)_2Al$ precipitate and the B2-(Ni,Co)Al matrix, respectively. (Ni,Co)Al hardens appreciably by the fine precipitation of the $(Ni,Co)_2Al$ phase. Energy dispersive spectroscopy was used to analyze the compositions of each phase formed in B2-(Ni,Co)Al.

• 한국결정성장학회지
• /
• 제31권2호
• /
• pp.78-83
• /
• 2021

본 연구에서는 수열반응법을 이용하여 3차원 구조를 갖는 NiCo2O4 입자를 합성했다. 수열합성에서 반응조건 [Ni]/[Co] 비율, 반응시간과 열처리온도를 달리하여 입자의 조성과 형상을 조절했다. 최적의 조건을 결정하고자 XRD, SEM을 통해 입자를 분석하였으며, [Ni]/[Co] 1:2 비율, 반응시간 12시간, 열처리 400℃ 4시간 조건에서 3차원 구조를 갖는 단일상의 NiCo2O4가 합성하였다. 합성된 NiCo2O4 나노구조체의 글루코스 센서 특성평가 결과, 글루코스에 대해 높은 민감도와 탁월한 선택성을 나타냈다. 본 연구를 통해 합성한 NiCo2O4 나노구조체는 향후 비효소 기반 전기화학적 글루코스 센서로 널리 응용될 수 있을 것으로 기대된다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
• /
• pp.109-109
• /
• 2011

CO oxidaition reacitvity of bare and $TiO_2$ -coated NiO/$Ni(OH)_2$ nanoparticles was studied. For the deposition of $TiO_2$ atomic layer deposition was used, and formation of three-dimensional island of $TiO_2$ on NiO/$Ni(OH)_2$ could be identified. Based on the data of X-ray Photoelectron Spectroscopy, we suggest that only $Ni(OH)_2$ existed on the surface, whereas NiO disappeared upon $TiO_2$ deposition. Both CO adsorption and CO oxidation took place on NiO/$Ni(OH)_2$ surfaces under our experimental conditions. CO adsorption was completely suppressed after $TiO_2$ deposition, whereas CO oxidation activity was maintained to large extent. It is proposed that bare NiO can uptake CO under our experimental condition, whereas hydroxylated surface of NiO can be active for CO oxidation.

• 한국자기학회지
• /
• 제9권6호
• /
• pp.296-300
• /
• 1999

DC 마그네트론 스퍼터링 방법으로 금속 마스크를 사용하여 십자형태로 substrate/Ta/NiFe/FeMn/NiFe/CoFe/Al2O3/CoFe/NiFe와 substrate/Ta/NiFe/CoFe/Al2O3/CoFe/NiFe/FeMn/NiFe 스핀 터널링 접합 구조를 제조하였다. 이러한 구조에서 절연층(Al2O3)의 형성조건과 각 층의 두께와 파워에 대한 증착율에 변화를 주어 24.3%의 자기 저항비를 얻었다. 두 종류의 구조에 대한 자기적 특성 비교와 Corning glass 7059와 Si(111) 기판의 종류에 따른 결과를 비교하였으며 소자 제조때 수반되는 온도변화에 대한 특성변화를 알아보고자 열처리를 하였다. 열처리 결과 자기 저항비는 15$0^{\circ}C$까지는 어느 정도 일정한 값을 유지하다가 18$0^{\circ}C$ 열처리 후 갑자기 감소하는 결과를 얻었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1996년도 춘계학술대회 논문집
• /
• pp.228-231
• /
• 1996

We prepared $LiCo_{1-x}Ni_{x}O_2$ by reacting stoichiometric mixture of LiOH.$H_2O$, $CoCO_3$.$xH_2O$ and $Ni(OH)_2$ (mole ratio respectively) and heating at $850^{\circ}C$ for 5h. We awared through XRD that from 0 to 0.5 at x in $LiCo_{1-x}Ni_{x}O_2$ is well formed for hexagonal structure, but the more $LiCo_{1-x}Ni_{x}O_2$ involve NI, the more hexagonal structure is not well formed. In the result of charge/discharge test, charge/discharge characteristic of $LiCo_{1-x}Ni_{x}O_2$ is similar to that of $LiCoO_2$. Therefore, $LiCo_{1-x}Ni_{x}O_2$ is superior to $LiCoO_2$ for Li secondary battery

• 한국분말재료학회지
• /
• 제25권4호
• /
• pp.296-301
• /
• 2018

In this study, an experiment is performed to recover the Li in $Li_2CO_3$ phase from the cathode active material NMC ($LiNiCoMnO_2$) in waste lithium ion batteries. Firstly, carbonation is performed to convert the LiNiO, LiCoO, and $Li_2MnO_3$ phases within the powder to $Li_2CO_3$ and NiO, CoO, and MnO. The carbonation for phase separation proceeds at a temperature range of $600^{\circ}C{\sim}800^{\circ}C$ in a $CO_2$ gas (300 cc/min) atmosphere. At $600{\sim}700^{\circ}C$, $Li_2CO_3$ and NiO, CoO, and MnO are not completely separated, while Li and other metallic compounds remain. At $800^{\circ}C$, we can confirm that LiNiO, LiCoO, and $Li_2MnO_3$ phases are separated into $Li_2CO_3$ and NiO, CoO, and MnO phases. After completing the phase separation, by using the solubility difference of $Li_2CO_3$ and NiO, CoO, and MnO, we set the ratio of solution (distilled water) to powder after carbonation as 30:1. Subsequently, water leaching is carried out. Then, the $Li_2CO_3$ within the solution melts and concentrates, while NiO, MnO, and CoO phases remain after filtering. Thus, $Li_2CO_3$ can be recovered.

• 한국표면공학회지
• /
• 제53권1호
• /
• pp.1-8
• /
• 2020

Sulfamate-chloride baths were fabricated to study the properties of the electrodeposited Ni and NiCo thin films. The dependences of current efficiency, deposit composition of Ni and Co, residual stress, surface morphology and microstructure of electrodeposited Ni and NiCo thin films on CoCl₂ concentration in sulfamate-chloride baths were investigated. The current efficiency was measured to be more than about 90%, independent of the changes of CoCl₂ concentration in the baths. Residual stress of Ni and NiCo thin films was increased from about 45 to about 250 MPa with varying CoCl₂ concentration from 0 to 0.210 M CoCl₂ in the baths and then reached to a plateau, about 250 MPa above 0.420 M CoCl₂ concentration. Nodular surface morphologies were observed at most CoCl₂ concentrations in the baths except 0.210 M. NiCo thin film electrodeposited from the bath with 0.210 M CoCl₂ concentration showed an acicular surface morphology. Pure Ni thin film consists of FCC(111), FCC(200), FCC(220), and FCC(311) peaks without any preferred orientation. On the other hand NiCo thin films make up of HCP(100), FCC(111), HCP(101), FCC(200), FCC(220) or HCP(110), FCC(311) or HCP(112) and FCC(222) peaks. It was revealed from the analysis of XRD result that FCC(111) peak at the NiCo thin film electrodeposited from the bath with 0.084 M CoCl₂ concentration can be regarded as the preferred orientation. However the peak of the preferred orientation was changed to FCC(220) or HCP(110) above 0.084 M CoCl₂ concentration in the baths. Then the intensity of FCC(220) or HCP(110) peak was gradually decreased with increasing CoCl₂ concentration further. The crystalline size of pure Ni thin film was observed to be about 53 ㎛ and those of NiCo thin films were in the range of 35~45 ㎛.

• International Journal of Advanced Culture Technology
• /
• 제3권2호
• /
• pp.110-117
• /
• 2015

10 wt% (Ni-Co) catalysts with different Ni and Co content : 10%Ni, 9%Ni1%Co, 7%Ni3%Co, 5%Ni5%Co, 3%Ni7%Co, and 10%Co; were prepared using sol-gel method followed by incipient wetness impregnation method. To investigate the catalytic activity including the stability, dry methane reforming were demonstrated over the pelletized catalysts at $620^{\circ}C$ under atmospheric pressure in a $CH_4:CO_2:N_2$ feedstock for 360 min. The results showed that bimetallic catalysts with the Co content equal to or greater than 3% were more stable than monometallic catalysts (10%Ni and 10%Co). The temperature programmed hydrogenation interpreted that the additional of Co into Ni catalyst improved the carbon resistance from methane cracking. Promoted this type of bimetallic catalyst using 1wt% K (trimetallic catalyst) prevented the carbon formation on the catalyst. The temperature programmed desorption of $CO_2$ indicated that this trimetallic catalyst has a greater number of strong basic sites. Moreover, the appearance of K lowered the number of weak basic sites and decreased the conversion of methane by 12 %.

• 대한화학회지
• /
• 제53권3호
• /
• pp.233-243
• /
• 2009

실리카지지 니켈(Ni-Si$O_2$), 실리카지지 구리(Cu-Si$O_2$), 몇가지 조성의 실리카지지 니켈과 구리의 합금(Ni/Cu-Si$O_2$)을 실온에서 일산화탄소(CO)의 압력을 넓은 범위에서 변화시키면서(0.2 $torr{\sim}$50 torr) 흡착된 CO의 적외선 스펙트럼을 1500 $cm^{-1}{\sim}2500\;cm^{-1}$ 범위에서 관찰했고 실온에서 진공탈착시키면서 흡착된 CO의 적외선 스펙트럼을 관찰했다. Ni-Si$O_2$에 CO를 흡착시켰을 때 2059.6 $cm^{-1},\;{\sim}$2036.5 $cm^{-1},\;{\sim}$1868.7 $cm^{-1},\;{\sim}$1697.1 $cm^{-1}$의 네 흡수띠가 관찰되었고, Cu-Si$O_2$에 일산화탄소를 흡착시켰을 때 $\sim$2115.5 $cm^{-1},\;{\sim}$1743.0 $cm^{-1}$ 두 흡수띠가 관찰되었으며, Ni/Cu-Si$O_2$에서는 ${\sim}2123.2\;cm^{-1}$, 2059.6 $cm^{-1},\;{\sim}$2036.4 $cm^{-1},\;{\sim}$1899.5 $cm^{-1},\;{\sim}$1697.1 $cm^{-1}$에 다섯 흡수띠가 관찰되었다. Ni/Cu-Si$O_2$, Cu-Si$O_2$, Ni/Cu-Si$O_2$에서 CO를 흡착시켰을 때 관찰된 흡수스펙트럼은 이전의 보고와 근사적으로 일치한다. 1800 $cm^{-1}$ 이하의 흡수띠는 Ni이나 Ni/Cu 합금의 스텦이 있는 결정표면에서 관찰된 바 있는데 Ni-Si$O_2$, Ni/Cu-Si$O_2$를 실온에서 CO를 흡착시켰을 때 나타나는 ${\sim}1697.1\;cm^{-1}$ 흡수띠는 Ni이나 Ni/Cu 합금 표면에서 스텦에 인접한 흡착자리에 흡착한 CO에 기인한 흡수띠로 제시할 수 있다. Cu-Si$O_2$ 시료를 실온에서 CO를 흡착시켰을 때 Cu 결정표면에서 2000 $cm^{-1}$ 이하의 흡수띠가 관찰되는 경우는 드문데 1743.0 $cm^{-1}$ 흡수띠는 Cu 표면의 스텦에 인접한 흡착자리에 흡착한 CO에 기인한 흡수띠로 제시할 수 있다. Ni/Cu-Si$O_2$에서 Cu의 함량이 몰분율 0.5까지 변함에 따라 같은 CO 압력 또는 같은 진공탈착시간에서 흡수띠의 위치가 21 $cm^{-1}$ 이하로 다른 ⅠB 금속을 첨가했을 때보다 작게 변하는데 Cu d 전자의 리간드 효과가 작은 현상에 기인한 것으로 볼 수 있다.