• Journal of the Korean institute of surface engineering
• /
• v.32 no.3
• /
• pp.360-362
• /
• 1999

Formation of the nickel-cadmium alloy in the negative electrode of nickel-cadmium cell subjected to continuous charging at elevated temperatures ($40~45^{\circ}C$) is shown to be one of the causes of the 'stepped' discharge curves. The alloy has been characterized by electrode potential measurement and X-ray diffraction method. The potential lowering during discharge is related to discharge of the alloy. X -ray diffraction suggests that the nickel-cadmium alloy can be formed during charge in negative electrode by interaction of the two metals. Addition of Ni $(OH)_2$ into $Cd{\;}(OH)_2$ active material is found to form the alloy more readily than sintered negative electrode alone.ode alone.

• Journal of Powder Materials
• /
• v.31 no.4
• /
• pp.318-323
• /
• 2024

Cemented carbide for cutting tools, which is composed of carbide as a hard phase and metallic component as a metallic phase, mainly uses cobalt as the metallic phase due to the excellent mechanical properties of cobalt. However, as the demand for machining difficult-to-machine materials such as titanium and carbon fiber-reinforced plastics has recently increased, the development of high-hardness cemented carbide is necessary and the replacement of cobalt metal with a high-hardness alloy is required. In this study, we would like to introduce high-hardness cemented carbide fabricated using nickel-tungsten alloy as the metallic phase. First, nickel-tungsten alloy powder of the composition for formation of intermetallic compound confirmed through thermodynamic calculations was synthesized, and cemented carbide was prepared through the sintering process of tungsten carbide and the synthesized alloy powder. Through evaluating the mechanical properties of high-hardness cemented carbide with the nickel-tungsten alloy binder, the possibility of producing high-hardness cemented carbide by using the alloys with high-hardness was confirmed.

• Journal of the Korean institute of surface engineering
• /
• v.29 no.6
• /
• pp.720-723
• /
• 1996

The behavior of electrodeposition of amorphous nickel-phosphorus has been studied from the point of deposition mechanism, kinetic parameters, morphology and formation of alloy films. The electorode reaction and electrode kinetics of deposition of nickel were significantly influenced by the content of phosphorus. The cathodic deposition of nickel-phosphorus alloy might be governed by the diffusion process of phosphorous acid. The direction of growth layer of the nickel-phosphorus alloy was different with substrate material. The formation of nickel-phosphorus alloy films was affected considerably by the solution compositions, electrolytic conditions and properties of the material as an underlayer.

• Corrosion Science and Technology
• /
• v.7 no.1
• /
• pp.61-67
• /
• 2008

In this paper, electrochemical and microstructural characteristics of nickel-plated Alloy 600 were investigated in order to identify the performance of electroless Ni-plating on Alloy 600 in high-temperature aqueous condition with the comparison of electrolytic nickel-plating. For high temperature corrosion test of nickel-plated Alloy 600, specimens were exposed for 770 hours to typical PWR primary water condition. During the test, open circuit potentials (OCP's) of all specimens were measured using a reference electrode. Also, resistance to flow accelerated corrosion (FAC) test was examined in order to check the durability of plated layers in high-velocity flow environment at high temperature. After exposures to high flow rate aqueous condition, the integrity of surfaces was confirmed by using both scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). For the field application, a remote process for electroless nickel-plating was demonstrated using a plate specimen with narrow gap on a laboratory scale. Finally, a practical seal design was suggested for more convenient application.

• Journal of the Korean institute of surface engineering
• /
• v.46 no.6
• /
• pp.235-241
• /
• 2013

In this study, the effects of alloying elements and thermal aging on the contact resistance of electroplated gold alloy layers were investigated by surface analysis using X-ray photoelectron spectroscopy (XPS). The contact resistance of Au-Ag alloy was lower than that of Au-Ni or Au-Co alloy after thermal aging. The XPS results show that nickel and oxygen present as nickel oxides such as NiO and $Ni_2O_3$ on the surface of gold layers after thermal aging. The increase in the contact resistance after thermal aging is attributable to the nickel oxide layer formed on the surface of the gold layers. The content of nickel diffused from the underlayer during the thermal aging was high in the order of Au-Co, Au-Ni and Au-Ag alloy because the area of grain boundary was large in the order of Au-Ag, Au-Ni and Au-Co alloy.

• Advances in materials Research
• /
• v.1 no.3
• /
• pp.169-182
• /
• 2012

In this paper the intrinsic influence of micron-sized nickel particle reinforcements on microstructure, micro-hardness tensile properties and tensile fracture behavior of nano-alumina particle reinforced magnesium alloy AZ31 composite is presented and discussed. The unreinforced magnesium alloy (AZ31) and the reinforced nanocomposite counterpart (AZ31/1.5 vol.% $Al_2O_3$/1.5 vol.% Ni] were manufactured by solidification processing followed by hot extrusion. The elastic modulus and yield strength of the nickel particle-reinforced magnesium alloy nano-composite was higher than both the unreinforced magnesium alloy and the unreinforced magnesium alloy nanocomposite (AZ31/1.5 vol.% $Al_2O_3$). The ultimate tensile strength of the nickel particle reinforced composite was noticeably lower than both the unreinforced nano-composite and the monolithic alloy (AZ31). The ductility, quantified by elongation-to-failure, of the reinforced nanocomposite was noticeably higher than both the unreinforced nano-composite and the monolithic alloy. Tensile fracture behavior of this novel material was essentially normal to the far-field stress axis and revealed microscopic features reminiscent of the occurrence of locally ductile failure mechanisms at the fine microscopic level.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.20 no.4
• /
• pp.478-483
• /
• 2011

Cast mold has low wear-resistance comparing with other alloyed molds which result in lower production rate and high cost of products. Recently, various weld methods are being applied to increase the wear-resistance of molds and to extend mold life. Among them, nickel alloy weld process increases the hardness irrelevant to its machinability and creates very uniform structures. In addition, it causes better wear-resistance and reduces shrinkage defects. In this paper, we analyze the mold surface cracks welded by nickel alloy and propose the methods to improve the mold surface and its wear-resistance. It has been found that nickel alloy weld does not affect the inside crack of mold but has an influence on the surface crack seriously. Results show that the start and growth of fatigue cracks have been delayed about 3 times and reduced approximately 75%, respectively, and the mold surface cracks are decreased about 5.7 times.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2000.04a
• /
• pp.264-269
• /
• 2000

Nickel-based heat resisting alloys are commonly used for high temperature applications such as in aircraft engines and gas turbines. In this paper, the machinability of Nickel-based heat resisting alloy was investigated with respect to the wear and the chip formation by tool type and cutting condition. Relationship between three types of tool and chip formation was experimentally investigated. Among the three types of tool tested, coated tools(CVD, PVD) are available for the difficult-to-cut-materials such as Nickel-based heat resisting alloy and etc..

• Journal of Hydrogen and New Energy
• /
• v.7 no.1
• /
• pp.63-69
• /
• 1996

Effect of nickel powder to added to the hydrogen absorbing alloy electrode of $MmNi_{4.5}-xCoxMn_{0.3}Al_{0.2}$ system alloy was investigated. The addition of nickel powder was effective for the improvement of discharging characteristic. It was found that the discharge capacity was 310mAhig when the alloy negative electrode was mixed $MmNi_{3.75}CO_{0.75}Mn_{0.3}Al_{0.2}$ and nickel powder with a mix of one to three. Still another, we have investigated thermodynamic stability of hydrogen in the alloy negative electrode. As a result, enthalpy of hydrogen and hydrogen equilibrium pressure in the alloy negative electrode were a suitable value to easy hydrogen absorption-desorption.

• Journal of Korean Society of societal Security
• /
• v.2 no.2
• /
• pp.63-68
• /
• 2009

Seismic design of newly built bridges can be considered and carried out during construction process according to the revised road bridge design standard issued recently. While for the existing reinforced concrete bridge priers under service before new standard implements, their resistance capacity against lateral seismic loading is inferior. In this research, seismic reinforcing for existing bridge piers by nickel-chrome alloy bar has been analyzed. Based on the established model by MIDAS program, the behaviors of bridge piers including deformation and stress with and without nickel-chrome alloy reinforcing bars have been compared and discussed under lateral seismic loading. And the advantages of using nickel-chrome alloy bar as seismic reinforcement over other materials, such as good performance, good economy etc. have been demonstrated by comparison with other researches. Also the anti-seismic efficiency of nickel-chrome alloy reinforcing bars has been confirmed by MIDAS modeling analysis.