• Corrosion Science and Technology
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• v.2 no.3
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• pp.148-154
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• 2003

The addition of Ni leads to the formation of protective rust layer on steel and subsequently high corrosion resistance of steel in $Cl^-$-containing environment. $\alpha$-FeOOH, $\beta$-FeOOH, $\gamma$-FeOOH and $Fe_3O_4$ are formed mainly on steels exposed to $Cl^-$-containing environment. As the first work of this kind, this study reports the influence of Ni on the oxidation behavior of $Ni_xFe_{1-x}(OH)_2$ in $Cl^-$-containing solution at two different pH regions(condition I under which the solution pH is allowed to decrease and condition I under which solution pH is maintained at 8) where $\gamma$-FeOOH and $Fe_3O_4$ are predominantly formed, respectively, upon oxidation of $Fe(OH)_2$, In the presence of Ni(II) in the starting solution, the formation of $\beta$-FeOOH was facilitated and the formation of $\gamma$-FeOOH was suppressed with increasing Ni(II) content and with increasing oxidation rate of Fe(II). Ni(II) was found to have $Fe_3O_4$-suppressing effect under condition II.

• Journal of the Korean Chemical Society
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• v.31 no.6
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• pp.509-519
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• 1987

The tetradentate Schiff base ligand, 3,4-bis(salicylidene diimine) toluene, have been prepared by the reaction of salicylaldehyde with 3,4-diaminotoluene by Duff method. The Schiff base ligand reacts with Ni(II), Co(II), and Cu(II) ions to form new complexes, [Ni(o-BSDT)${\cdot}(H_2O)_2$], [Co(o-BSDT)${\cdot}(H_2O)$], and [Cu(o-BSDT)]. It seems that Ni(II) and Ni(II) complexes are hexacoordinated with the Schiff base ligand and two molecules of water, while the Cu(II) complexes are tetracoordinated with the Schiff base. The mole ratio of tetradentate Schiff base ligand to metals was found to be 1 : 1. The redox chemistry of these complexes was investigated by polarography and cyclic voltammetry with glassy carbon electrode in DMSO with 0.1M TEAP${\cdot}$[Ni(o-BSDT)${\cdot}(H_2O)_2$] hav EC reaction mechanisms which undergo a irreversible electron transfer followed by a fast chemical reaction. [Co(o-BSDT)${\cdot}(H_2O)_2$] undergoes a reduction of Co(II) to Co(I) and a oxidation of Co(II) to Co(III), and [Cu(o-BSDT)] undergoes a reduction of Cu(II) to Cu(I).

• Journal of the Korean Ceramic Society
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• v.42 no.5 s.276
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• pp.319-325
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• 2005

[ $LiNiO_2$ ] was synthesized by the solid-state method after mixing $LiOH{\cdot}H_2O$ and $Ni(OH)_2$ with SPEX mill. The optimum condition for the synthesis of $LiNiO_2$ was the calcination at $750^{\circ}C$ for 30h in $O_2$ stream after milling for 1 h. The $LiNiO_2$ synthesized under this condition showed relatively large value of $I_{003}/I_{104}$ and relatively small value of R-factor. When $LiNiO_2$ was cycled in 2.7$\~$4.15 V at 0.1C-rate, the first discharge capacity was not very large (145.8 mAh/g) but it showed good cycling performance. When $LiNiO_2$ was cycled in 2.7$\~$4.2 V at 0.1C-rate, the first discharge capacity was large but ,it showed poor cycling performance probably because of the transition of H2 hexagonal structure to H3 hexagonal structure. In addition, when $LiNiO_2$ was cycled in 1.0$\~$4.8 V at 1/24C- rate, the first discharge capacity was very large (257.7 mAh/g) and the discharge capacity increased with the number of cycles.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.119-123
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• 1997

The complex [Ni(L)]I2 (1) (L:3,5,10,12-Tetramethly-1,4,8,11-tetraazacyclotetradecane) has been prepared and characterized by X-ray diffraction methods. The complex 1 crystallized in the orthorhombic system, space group Pcab with cell parameters a=13.293(1) Å, b=28.550(7) Å, c=10.804(1) Å, z=8. Least-squares refinement of 1 led to a R(Rw) factor of 0.043 (0.046) for 1851 observed reflections of Fo>3o (Fo). The crystal structure of 1 has a slightly distorted square-planar geometry and adopts the trans-III conformation.

• Proceedings of the Korean Vacuum Society Conference
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• 1999.07a
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• pp.174-174
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• 1999

Pt(001)의 깨끗한 표면은 재배열된 (5x20) 또는 (nxn) 구조를 갖는다. 이러한 재배열된 구조는 소？의 가스를 흡착에 대해서도 (1x1)구조로 다시 재배열되는 재배열인 쉽게 풀리는 준안정적 재배열 구조를 갖는 표면이다. Pt(100) 표면 위에 Ni과 같은 금속을 흡착시키는 경우도 동일하게 표면의 장력을 해소시켜 (1x1) 표면을 만든다. Pt와 Ni과 같은 덩어리 상태에서 Pt와 Ni가 질서있게 교차되어 배열되는 합금이 쉽게 이루어지는 물질들로 잘 알려져 있고, 이 합금은 Pt나 Ni와 동일한 규칙적인 fcc 구조를 갖는다. 따라서 Pt(100) 표면 위에 Ni를 흡착시키는 것은 Nm/Cu(100)과 같은 표면합금이나 Mn/Ag(1000에서 보이는 2층으로 된 표면 합금과 같은 표면 근방에 국한된 질서있는 표면 합금의 가능성이 있다. 또한 Ni/Pt(100)은 Ni과 Pt가 3대 1의 비로 조합될 때 나타나는 Ni3Pt의 층별구조인 표면에 Ni가 채워져 있고, 다음 층에 Ni와 Pt가 50%씩 질서 있게 섞여 있는 형태의 구조 즉 표면 밑 합금이 나타날 수 있는 가능성이 있는 물질계라는 점에서 관심을 갖게 한다. 본 연구는 LEED를 이용하여 Ni/Pt(100) 박막의 층별구조를 확인하고자 한다. PtNi 합금은 ATA(average t-matirx approximation)을 이용한 LEED 분석이 잘 적용되는 물질계로 알려져 있고, 본 연구는 ATA를 적용한 LEED I/V 분석을 통하여 Ni가 성장된 Pt(100) 표면의층별 농도비와 층별 구조를 구하고자 한다. 실험은 기본 압력이 3x10-11torr인 챔버에서 이루어졌으며, 증착시 압력은 5x10 torr이고, 증착은 열증발 방법을 이용하였다. Ni가 증착됨에 따라 (nxn) 재배열 표면에 기인한 extra spot들의 세기는 점차 감소하고 특정 증착량 이상에서부터 이 (nxn)의 spot들이 사라지고 깨끗한 (1x1) 패턴이 나타난다. 계속되는 증착량의 증가에 대해서도 이 (1x1) 형태는 유지되며, 표면의 질서에 따르는 c(2x20 패턴은 보이지 않았다. (1x1) LEED spot를 보임에도 불구하고 덩어리 절단 형태의 구조를 기반으로 한 LEED I/V 분석으로는 잘 맞출수 없었다. 이것은 Ni가 일정 이상 흡착된 경우 그 구조가 덩어리 절단 형태의 fcc(100) 구조와 벗어난 구조를 가지는 것으로 보인다.

• Journal of the Korean Society for Heat Treatment
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• v.14 no.1
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• pp.1-7
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• 2001

A method to simultaneously synthesize and consolidate the silicide $NiSi_2$ and the composite $NiSi_2$-20vol.%Nb from powders of Ni, Si, and Nb was investigated. Combustion synthesis was carried out under the combined effect of an electric field and mechanical pressure. The final density of the products increased nearly linearly with the applied pressure. Highly dense $NiSi_2$ and $NiSi_2$-20vol.%Nb with relative densities of up to 97% were produced under the simultaneous application of a 60MPa pressure and a 3000A current on the reactant powders. The respective Vickers microhardness values for these materials were 6.0 and 5.8 GPa. From indentation crack measurements, the fracture toughness values for $NiSi_2$ and $NiSi_2$-20vol.%Nb were calculated to be 3.3 and 4.7 $MPa{\cdot}m^{1/2}$, respectively.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.11
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• pp.968-972
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• 2008

Ni/Ti/Al multilayer system ('/'denotes the deposition sequence) was tested for low-resistance ohmic contact formation to Al-implanted p-type 4H-SiC. Ni 30 nm / Ti 50 nm / Al 300 nm layers were sequentially deposited by e-beam evaporation on the 4H-SiC samples which were implanted with Al (norminal doping concentration = $4\times10^{19}cm^{-3}$) and then annealed at $1700^{\circ}C$ for dopant activation. Rapid thermal anneal (RTA) temperature for ohmic contact formation was varied in the range of $840\sim930^{\circ}C$. Specific contact resistances were extracted from the measured current vs. voltage (I-V) data of linear- and circular transfer length method (TLM) patterns. In constrast to Ni contact, Ni/Ti/Al contact shows perfectly linear I-V characteristics, and possesses much lower contact resistance of about $2\sim3\times10^{-4}\Omega{\cdot}cm^2$ even after low-temperature RTA at $840^{\circ}C$, which is about 2 orders of magnitude smaller than that of Ni contact. Therefore, it was shown that RTA temperature for ohmic contact formation can be lowered to at least $840^{\circ}C$ without significant compromise of contact resistance. X-ray diffraction (XRD) analysis indicated the existence of intermetallic compounds of Ni and Al as well as $NiSi_{1-x}$, but characteristic peaks of $Ti_{3}SiC_2$, a probable narrow-gap interfacial alloy responsible for low-resistance Ti/Al ohmic contact formation, were not detected. Therefore, Al in-diffusion into SiC surface region is considered to be the dominant mechanism of improvement in conduction behavior of Ni/Ti/Al contact.

• Analytical Science and Technology
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• v.13 no.2
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• pp.194-199
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• 2000

The study on the adsorption, the surface properties and the antibacterial effects of the Ni-treated PAN based activated carbon fibers was carried out. In the adsorption study on the Ni-treated PAN based ACFs, Type I isotherms for N1-N3 and Type II-Type III isotherms for N4-N6 were obtained, respectively. Futhermore, their adsorbed volumes slowly were decreased with the increase in the mole concentration of Ni on the treated PAN based ACFs. From the BET equation, the specific surface areas of the Ni-treated PAN based ACFs were in the range of $692.58-895.24m^2/g$. The micropore volumes obtained from ${\alpha}_s$-method using common-t value were $0.19-0.56cm^3/g$. The surfaces of PAN based ACFs partially blocked by metal after the treatment were observed from the SEM micrographs. Finally, from the antibacterial effects using Shake flask method against E. coli, the percentage of the effects was 92.5-100% and the antibacterial effect was increased with the increase in mole concentration of Ni treated.

• Progress in Superconductivity
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• v.8 no.1
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• pp.27-32
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• 2006

[$YBa_2Cu_3O_{7-x}$] thin films were deposited on various buffered-templates by a metal organic chemical vapor deposition(MOCVD). Three different templates of $CeO_2/YSZ/CeO_2/pure-Ni(CYC),\;CeO_2/YSZ/Y_2O_3/Ni-3at.%W(YYC)$ and $CeO_2/IBAD-YSZ$/stainless steel were used. The Ni and Ni-W alloy tapes were biaxially textured by cold rolling and annealing heat treatment. The dense YBCO films were grown on both the IBAD and YYC templates with no microcrack, while the YBCO films on the CYC templates were grown with the formation of microcracks and NiO. The YBCO film on the YYC template showed the higher $I_c$ than that on CYC template. Especially, the IBAD templates with a thin $CeO_2$(type I) and thick $CeO_2$(type II) top layer were used to compare the deposition nature of the YBCO on them. Comparing the current property of the YBCO films on IBAD templates, the YBCO film deposited on thick $CeO_2$ layer was better than the film on thin $CeO_2$ layer.

• 한국전기화학회:학술대회논문집
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• 2004.06a
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• pp.281-286
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• 2004

[ $LiOH{\cdot}H^2O$ ]와 $Ni(OH)^2$를 기계적으로 혼합하여 고상법으로 $LiNiO^2$를 합성하고, $LiNiO^2$의 전기화학적 특성을 조사하였다. 기계적 혼합을 위해 SPEC mill을 사용하였으며, 1시간 동안 milling하여 공기 중 $450^{\circ}C$에서 5시간 동안 전처리한 후 $750^{\circ}C$에서 30시간 동안 산소를 흘려주면서 하소한 시료가 가장 좋은 전기화학적 특성을 나타내었다. $2.7\~4.15V$에서 0.1C로 충${\cdot}$방전시 초기방전용량은 그다지 높지 않았으나(145.8mAh/g) 좋은 싸이클 성능을 나타내었으며, $2.7\~4.2V$에서 0.1C로 충${\cdot}$방전시 높은 초기방전용량(164.7mAh/g)을 나타내었으나 싸비클 성능은 그리 좋지 않았는데, 이는 충${\cdot}$방전시 육방구조$(H^2)$에서 육방구조$(H^3)$로의 상전이가 영향을 주는 것으로 사료된다. 초기방전용량과 방전용량은 Cation mixing을 나타내는 $I^{003}/I^{104}$값보다 hexagonal ordering을 나타내는 R-factor에 더 의존하는 것으로 사료된다.