• 한국표면공학회지
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• 제35권2호
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• pp.93-100
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• 2002

To better understand the codeposition mechanism of phosphorous, surface pH and potential of cathode were measured during electrodeposition of Ni-P alloys. The pH of cathode surface was measured using a flat-bottom glass pH electrode and a 500 mesh gold gauze as cathode. The cathode surface pH was increased with increasing the current density and always higher than the pH in the bulk solution. As a result of overplotting the surface pH and cathode potential on the Pourbaix diagram, it was found that cathode surface shift to the domain of predominant of $H_2$$PO3$-or $H_2$$PO_2$-. Additionally, new deposition mechanism was suggested that $H_2$ $PO_2$- and $H_2$$PO_3$- play important roles in the deposition reaction of Ni-P alloys.

• 연구논문집
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• 통권31호
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• pp.127-133
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• 2001

In chromium electrodeposition, crack is inevitably accompanied by chromium layer. Behavior of crack formation and crack density were different from the plating conditions such as current density, temperature, waveform of applied current and so on. And cracks have an influence on the corrosion resistance of chromium deposit, because corrosion occurs through the network of cracks between deposit and substrate. Therefore, many researches have been achieved in order to remove the cracks in chromium deposit. Formation of double layers, Cr/Cr and Ni/Cr were investigated to increase corrosion resistance of chromium deposit in this study. As pretreatment prior to outer chromium coating, acid pickling and current control method were examined. Cracks in cross-section of each sample were observed with SEM and CASS(Copper modified acetic acid salt spray) test was performed to evaluate corrosion resistance. It was found that corrosion resistance of Cr/Cr and Ni/Cr double layers were superior to Cr or Ni single layer from the results of CASS test.

• 한국표면공학회지
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• 제47권5호
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• pp.215-220
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• 2014

Electrodeposition behaviors of Pd-Ni alloys were investigated from the polarization curves in a solution containing ethylenediamine as complexing agent. The microstructure and hardness of electrodeposited Pd-Ni alloys were also characterized. Codeposition of Pd-Ni alloys was successfully performed in the wide current density ranging from 2 to $5000A{\cdot}m^{-2}$ because the deposition potential of Pd became close to that of Ni in the ethylenediamine-contained solution. It was also found from X-ray diffraction patterns that the solid solution between Pd and Ni was formed with variation of the composition of alloys. The measured hardness of Pd-Ni alloys increased with increasing the contents of Ni due to solid solution strengthening and grain refinement. The electrodeposited Pd-Ni alloys also exhibited a crack free smooth surface morphology from the SEM observation.

• 대한금속재료학회지
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• 제46권7호
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• pp.420-426
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• 2008

By using electrodeposition, we developed a new method to produce Ni/Invar bimetal sheets, which have been used for the present study to investigate the texture evolution during annealing. The grains of electrodeposited Ni were columnar, while those of electrodeposited Fe-Ni alloy were nanocrystalline. These different parts of the bimetal underwent different evolution of textures and microstructures during annealing. In the nanocrystalline Invar, the as-deposited textures were of fiber-type characterized by strong <100>//ND and weak <111>//ND components, and the occurrence of grain growth resulted in the strong development of the <111>//ND fiber texture with the minor <100> // ND components. On the other hand, in the columnar-structured Ni part, the as-deposited <110>//ND fiber texture transformed to the <112>//ND fiber texture due to recrystallization occurring above $550^{\circ}C$. The development of microtextures which took place during annealing in the Ni/Invar interfacial regions was investigated by using the OIM analysis, and discussed in terms of the effect of atomic diffusion across the interfaces.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 추계학술발표회 초록집
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• pp.90-91
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• 1999

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 1999년도 추계학술발표회 초록집
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• pp.39-39
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• 1999

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2003년도 춘계학술발표회 초록집
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• pp.49-49
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• 2003

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2011년도 춘계학술대회 및 Fine pattern PCB 표면 처리 기술 워크샵
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• pp.153-153
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• 2011

Ni $TiO_2$ nano composite coatings were fabricated by using pulse current electrodeposition technique at 100 Hz pulse frequency with a constant 50% pulse duty cycles and reference was taken with respect to the direct current electrodeposition. The properties of the composite coatings were investigated by using SEM, XRD, Wear test and Vicker's microhardness test. XRD patterns of pulse deposited composite coatings were found to be changed from preferred (100) orientation to the random mixed orientations. The results demonstrated that the Vickers microhardness of composite coatings under pulse condition was significantly improved than that of pure nickel coating as well as direct current electrodeposited Ni-$TiO_2$ composite coatings. Wear tracks have shown the less plastic deformation at pulse condition with reduced coefficient of friction. Nickel matrix grain size was also found to be lower in pulse plated composite coatings as compared to direct current electrodeposited composite coatings.

• 한국표면공학회지
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• 제43권6호
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• pp.283-288
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• 2010

Ni-$TiO_2$ nano composite coatings were fabricated using pulse current electrodeposition technique at 100 Hz pulse frequency with a constant 50% pulse duty cycles and reference was taken with respect to the direct current (dc) electrodeposition. The properties of the composite coatings were investigated by using SEM, XRD, Wear test and Vicker's microhardness test. Pulse electrodeposited composite has exhibited enhancement of (111), (220), and (311) diffraction lines with an attenuation of (200) line. The results demonstrated that the microhardness of composite coatings under pulse condition was significantly improved than that of pure nickel coating as well as dc electrodeposited Ni-$TiO_2$ composite coatings. Wear tracks have shown the less plastic deformation in pulse plated composite. Coefficient of friction was also found to be lower in pulse plated composite coatings as compared to dc plated composite coatings.

• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.26.1-26.1
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• 2010

Ni-SiC nano composite coatings were fabricated using electrodeposition technique with the aid of ultrasound. The properties of the nano composite were investigated by using SEM, XRD, Wear test and Vicker's microhardness test. The results demonstrated that the microhardness of composite coatings under ultrasonic condition was improved significantly as compared to conventional electrodeposition techniques without ultrasound. The nano particles were found to be distributed homogeneously with reduced agglomeration. The synergistic combination of superior wear resistance and improved microhardness was found in ultrasonicated conditions to the Ni-SiC nano composite coatings.