• 한국표면공학회지
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• 제38권5호
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• pp.198-201
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• 2005

Nickel amalgam was Prepared by the electro-deposition with mercury cathode in a modified Watts bath. Homogeneous nickel amalgam was obtained. The fluidity of the amalgam decreased gradually with increased nickel quantity and become solid finally. Nickel powders of sub-micron size were obtained by a distillation of mercury from the amalgam. The characterization of the nickel amalgam was studied by SEM and x-ray diffractometry.

• 한국표면공학회지
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• 제16권1호
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• pp.3-9
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• 1983

The change of the hardness and yield strength depending upon the electrolysis conditions was investigated for Watts and bright nickel electrodeposits. The hardness of Watts nickel electrodeposits decreased with increasing current density in the range of 1-15A/Am2, while it increased with increasing bath temperature. The hardness of bright nickel deposits increased noticebly in comparison with that of Watts nickel electro-deposits. The hardness and the yield strength of the bright nickel electrodeposits increased considerably with decreasing current density and the highest value was obtained at the lowest current density (1A/dm2), while they decreased noticebly at the bath temperature of 80$^{\circ}C$ in comparison with that of 40-60$^{\circ}C$. The change of the hardness and the yield strength of bright nickel electrodeposits depending upon the electrolysis conditions could be mainly attributed to the variation of organic additives codeposited in the electrodeposits. The recrystallizatioin temperature(50% softening temperature) of the Wattss and the bright nickel electro-deposits was 520-280$^{\circ}C$ and 350-410$^{\circ}C$ respectively and then the recystallization temperature of bright nickel deposits was lower than that of the Watts nickel electrodeposits.

• 한국초전도학회:학술대회논문집
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• 한국초전도학회 2000년도 High Temperature Superconductivity Vol.X
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• pp.289-292
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• 2000

In order to evade the patent of Oak Ridge National Laboratory (RABiTS process) and search for more economical process, a new process for producing the biaxially textured Ni tape by electrodeposition has been investigated. Electrodeposition was performed in the modified Watts bath. The crystal orientations of electrodeposited Ni were analysed by X-ray pole figure, ${\phi}$-scan and ${\omega}$-scan. The electrodeposited Ni tape showed cube texture with good out-of plane(< 8${\circ}$) and in-plane alignment(< 20${\circ}$).

• International Journal of Advanced Culture Technology
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• 제3권1호
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• pp.120-128
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• 2015

In this paper, Residential roof top photovoltaic system with 9.9 kW design is proposed. The system composed of 200 Watts solar array 33 panels connecting in series 10 strings and parallels 3 strings which have maximum voltage and current are 350 V and 23.8 A. The 10 kW sinusoidal grid-connected inverter with window voltage about 270-350 is selected to convert and transfer DC Power to AC Power at PCC (Point of Common Coupling) of power system following to utility standard. However the impact of fluctuation and uncertainty of weather condition of PV may decrease the voltage stability and voltage collapse of power system. In order to solve this problem the energy storage such 120 V 1200 Ah battery bank and 30 kVAR capacitor are designed for voltage stability control. The other expensed for installing the system such battery charger, cable, accessories and maintenance cost are concerned. The economic analysis by using investment from money loan with interest about 7% and use own money which loss income of deposit about 3% are calculated as 671,844 and 547,044 for PV system with energy storage and non energy storage respectively. The solar energy from PV is about 101,616 Bath per year which evaluated by using the value of $5kWh/m^2/day$ from average peak sun hour (PSH) of the Thailand and 6.96 Bath/kWh of Feed in Tariff Incentive. The payback periods of four scenarios are proposed follow as i) PV system with energy storage and use loan money is 15 years ii) PV system with no energy storage and use loan money is 10 years iii) PV system with energy storage and use deposit money is 9 years iv) PV system with energy storage and use deposit money is 7 years. In addition, the other scenarios of economic analysis such no FIT support and other type of economic analysis such NPV and IRR are proposed in this paper.

• 한국산업융합학회 논문집
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• 제25권6_2호
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• pp.1037-1045
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• 2022

In this study, nanoscale Al₂O3 ceramic particles were used due its exceptionally high hardness characteristics, chemical stability, and wear resistance properties. These nanoparticles will be used to investigate the optimal process conditions for the electro co-deposition of the Ni-Al₂O₃ composite coatings. A Watts bath electrolytic solution of a controlled composition along with a fixed agitation speed was used for this study. Whereas the current density, the pH value, temperature and concentration of the nano Al₂O₃ particles of the electrolyte were designated as the manipulative variables. The experimental design method was based on the orthogonal array to find the optimum processing parameters for the electro co-deposition of Ni-Al₂O₃ composite coatings. The result of confirmation experimental based on the optimal processing condition through the analysis of variance ; EDX analysis found that the ratio of alumina increased to 8.65 wt.% and subsequently the overall hardness increased to 983 Hv. Specially, alumina were evenly distributed on Nickel matrix and particles were embedded more firmly and finely in Nickel matrix.

• 한국재료학회지
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• 제20권8호
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• pp.439-443
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• 2010

Nano sized SiC particles (270 nm) are easily agglomerated in nickel sulfamate electrolytic bath during a composite electrodeposition process. The agglomeration of nano particles in composite coatings can significantly reduce the mechanical properties of the composite coatings. In this study, Ni-SiC nano composite coatings were fabricated using a conventional electrodeposition process with the aid of ultrasound. Nano particles were found to be distributed homogeneously with reduced agglomeration in the ultrasonicated samples. Substantial improvements in mechanical properties were observed in the composite coatings prepared in presence of ultrasound over those without ultrasound. Ni-SiC composite coatings were prepared with variable ultrasonic frequencies ranging from 24 kHz to 78 kHz and ultrasonic powers up to 300 watts. The ultrasonic frequency of 38 kHz with ultrasonic power of 200 watt was revealed to be the best ultrasonic conditions for homogeneous dispersion of nano SiC particles with improved mechanical properties in the composite coatings. The microstructures, phase compositions, and mechanical properties of the composite coatings were observed and evaluated using SEM, XRD, Vickers microhardness, and wear test. The Vickers microhardness of composite coatings under ultrasonic condition was significantly improved as compared to the coatings without ultrasound. The friction coefficient of the composite coating prepared with an ultrasonic condition was also smaller than the pure nickel coatings. A synergistic combination of superior wear resistance and improved microhardness was found in the Ni-SiC composite coatings prepared with ultrasonic conditions.

• 한국수소및신에너지학회논문집
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• 제29권6호
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• pp.549-558
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• 2018

The overall efficiency depend on the overpotential of the oxygen evolution reaction in alkaline water electrolysis. Therefore, it is necessary to research to reduce the oxygen evolution overpotential of electrodes. In this study, Ni-Zn-Fe electrodes were prepared by electroplating and the surface area was increased by Zn leaching process. Electroplating variables were studied to optimize the plating parameters(electroplating current density, pH value of electroplating solution, Ni/Fe content ratio). Ni-Zn-Fe electrode, which is electroplated in a modified Watts bath, showed 0.294 V of overpotential at $0.1A/cm^2$. That result is better than that of Ni and Ni-Zn plated electrodes. As the electroplating current density of the Ni-Zn-Fe electrode increased, the particle size tended to increase and the overpotential of oxygen evolution reaction decreased. As reducing pH of electroplating solution from 4 to 2, Fe content in electrode and activity of oxygen evolution reaction decreased.