• 한국재료학회지
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• 제15권5호
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• pp.318-322
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• 2005

Ti-capped NiSi contacts were formed on $p^+/n$ junctions to improve the leakage problem and then Cu was deposited without removing the Ti-capping layer in an attempt to utilize as a diffusion barrier. The electrical characteristics of these $p^+/n$ diodes with Cu/Ti/NiSi electrodes were measured as a function of drive-in RTA(rapid-thermal annealing) and silicidation temperature and time. When drive-in annealed at $900^{\circ}C$, 10 sec. and silicided at $500^{\circ}C$, 100 sec., the diodes showed the most excellent I-V characteristics. Especially, the leakage current was $10^{-10}A$, much lower than reported data for diodes with NiSi contacts. However, when the $p^+/n$ diodes with Cu/Ti/NiSi contacts were furnace-annealed at $400^{\circ}C$ for 40 min., the leakage current increased by 4 orders. The FESEM and AES analysis revealed that the Ti-capping layer effectively prohibited the Cu diffusion, but was ineffective against the NiSi dissociation and consequent Ni diffusion.

• 열처리공학회지
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• 제20권1호
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• pp.11-16
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• 2007

The fatigue properties of Ti-Ni shape memory alloy wires were investigated. In Ni-rich Ti-Ni shape memory alloys, $Ti_3Ni_4$ precipitates formed by aging treatments are believed to vary the shape memory and mechanical properties. In this study, the effect of aging temperature and aging time on shape memory properties and fatigue life were investigated using Ti-50.9 at% Ni alloy wires. The specimens were solution-treated at 1073 K for 3.6 ks followed by aging at 573 K, 673 K and 773 K for periods between 3.6 ks and 3600 ks. It was found that the fatigue life under a constant stress decreased with increasing aging temperature. When the specimens were aged at 573 K for periods between 36 ks and 360 ks, superior shape memory and fatigue properties were obtained. The fatigue life also decreased when the test temperature and strain amplitude increased. It was concluded that the fatigue life exhibited a linear relationship with the critical stress for slip.

• 대한금속재료학회지
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• 제50권11호
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• pp.855-859
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• 2012

Samples with compositions of 80 wt% Mg-14 wt% Ni-6 wt% $Fe_2O_3$ and 80 wt% Mg-14 wt% Ni-6 wt% Ti were prepared by mechanical grinding under hydrogen (reactive mechanical grinding). Their hydrogen absorptions during reactive mechanical grinding were examined. TGA and BET analysis were employed to investigate the hydrogen storage properties of the prepared alloys. TGA analysis of the $Mg-14Ni-6Fe_2O_3$ showed an absorbed hydrogen quantity of 6.91 wt% while that of Mg-14Ni-6Ti was 2.59 wt%. BET analysis showed that the specific surface areas of $Mg-14Ni-6Fe_2O_3$ and Mg-14Ni-6Ti after reactive mechanical grinding were $264m^2/g$ and $64m^2/g$, respectively. The larger absorbed hydrogen quantity and the larger specific surface area of $Mg-14Ni-6Fe_2O_3$ after RMG than those of Mg-14Ni-6Ti after RMG showed that the effects of $Fe_2O_3$ addition are much stronger than those of Ti addition during reactive mechanical grinding.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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• pp.1257-1258
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• 2006

Biomimetic apatite deposition behaviors and mechanical performance for as-rolled and annealed Ni-Ti plates were investigated . A good biomimetic apatite formation and excellent mechanical performance of Ni-Ti suggests that Ni-Ti can be an excellent candidate material as orthopedic implants.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.64-65
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• 2008

본 연구에서는 임상적으로 사용후 파절된 Ni-Ti파일의 표면 거동을 조사해보고 피로파괴수명 연장을 위하여 표면에 TiN/Ti 및 ZrN/Ti를 다층막으로 코팅한 후 표면의 특성을 조사하였다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2008년도 추계학술대회 초록집
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• pp.66-67
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• 2008

본 연구에서는 코팅된 Ni-Ti파일의 이온용출을 조사하기 위하여 표면에 형성된 TiN/Ti 및 ZrN/Ti다층막의 구강유사액에서 표면의 부식특성을 조사하였다.

• 대한치과기공학회지
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• 제23권1호
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• pp.9-19
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• 2001

Microstructure and phase transformation of Ti-Ni-Cu alloy powders produced by using attrition milling method were studied. Mixed powders of Ti-(50-X)Ni-XCu ($X=0{\sim}20$ at%) in composition range were mechanically alloyed for maximum 20 hours by using SUS 1/4" ball in argon atmosphere. Ball to powder ratio was 50: 1 and impeller speed was 350rpm. Mechanically alloyed with attrition millimg method. powder was heat treated at the temperature up to $850^{\circ}C$ for 1 hour in the $10^{-6}$ torr vacuum. Ti-Ni-Cu alloy powders have been fabricated by attrition milling method. and then phase transformation behaviours and microstructual properties of the alloy powders were investigated to assist in improving the the high damping capacity of Ti-Ni-Cu shape memory alloy powders. The results obtained are as follows: 1. After heat treating of fully mechanically alloyed powder at $850^{\circ}C$ for 1hour. most of the B2 and B 19' phases was formed and $TiNi_3$ were coexisted. 2. The B 19' martensite were formed in Ti-Ni-Cu alloy powders whose Cu-content is less than 5a/o. where as the B19 martensite in those whose Cu-content is more than 10at%. 3. The powders of as-milled Ti-Ni-Cu alloys whose Cu-contents is less than 5at% are amorphous. whereas those of as-milled Ti-Ni-Cu alloys whose Cu-content is more than 10at% are crystalline. This means that Cu addition tends to suppress amorphization of Ti-Ni alloy powders.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2011년도 추계학술대회 초록집
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• pp.100-100
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• 2011

Nanomaterial architecture with highly ordered, vertically oriented $TiO_2$ nanotube arrays shows a good promise for diverse technological applications. As inspired from the literature reports that Nickel modification can improve the photocatalytic activity of $TiO_2$, it was planned to coat Ni into the $TiO_2$ matrix. In this study, first $TiO_2$ nanotubes(TiNTs) were prepared by anodization (60V,3min) in HF-free aqueous electrolyte on ultrasonically cleaned polished titanium sheet substrates ($1{\times}7cm^2$). The typical thickness of the sintered TiNT ($500^{\circ}C$for10min) was ~1 micronas confirmed from the FESEM study. In the next part, as-anodized and sintered TiNT/Ti photoanodes were used to coat Ni by AC electrodeposition from aqueous 0.1M nickel sulphate solution. During AC electrodeposition, conditions such as 1V DC offset voltage, 9V amplitude (peak-to-peak) and 750 Hz frequency were fixed constant and the deposition time was varied as 0.5 min, 1 min, 2 min and 10 min. The photoelectrochemical performance of pristine and Ni modified TiNT/Ti photoanodes was measured in 1N NaOH electrolyte under 1 SUN illumination in the potential range of -1V and 1.2V versus Ag/AgCl reference electrode. The photocurrent performance of TiNT/Ti photoanode decreased upon Ni modification and the results were confirmed after repeated experiments. This suggests us that Ni modification inhibits the photoelectrochemical performance of $TiO_2$ nanotubes.

• Journal of Industrial and Engineering Chemistry
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• 제68권
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• pp.325-334
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• 2018

Lactose is a reducing disaccharide consisting of two different monosaccharides such as galactose and glucose. The hydrogenation of lactose to lactitol is a formidable challenge because it is a complex process and several side products are formed. In this work, we synthesized Ru-Ni bimetallic nanohybrids as efficient catalysts for selective lactose hydrogenation to give selective lactitol. Ru-Ni bimetallic nanohybrids with $Ru-NiO_x$ (x = 1, 5, and 10 wt%) are prepared by impregnating Ru and Ni salts precursors with $TiO_2$ used as support material. Ru-Ni bimetallic nanohybrids (represented as $5Ru-5NiO/TiO_2$) catalyst is found to exhibit the remarkably high selectivity of lactitol (99.4%) and turnover frequency i.e. ($374h^{-1}$). In contrast, monometallic $Ru/TiO_2$ catalyst shows poor performance with ($TOF=251h^{-1}$). The detailed characterizations confirmed a strong interaction between Ru and NiO species, demonstrating a synergistic effect on the improvement on lactitol selectivity. The impregnation-reduction method for the preparation of bimetallic $Ru-NiO/TiO_2$ catalyst promoted Ru nanoparticles dispersed on NiO and intensified the interaction between Ru and NiO species. $Ru-NiO/TiO_2$ efficiently catalyzed the hydrogenation of lactose to lactitol with high yield/selectivity at almost complete conversion of lactose at $120^{\circ}C$ and 55 bar of hydrogen ($H_2$) pressure. Moreover, $Ru-NiO/TiO_2$ catalyst could also be easily recovered and reused up to four runs without notable change in original activity.

• The Korean Journal of Ceramics
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• 제3권2호
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• pp.124-128
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• 1997

An attempt was made to understand the dissolution and reprecipitation behavior of the constituent phases such as TiC, TiN, and Ti(CN) in TiC-TiN-Ni system. During the liquid-phase sintering the TiC phase was found to dissolve preferentially in Ni binder. The solid-solution phase, Ti(CN), formed around the TiN phase, resulting in a core/rim structure. This result was reproduced when large TiC particles were used with fine TiN particles. The path for the microstructural change in TiC-TiN-Ni system was largely controlled by the difference in the interfacial energy of each phase with the liquid binder phase. The results were discussed with thermodynamic principles.