• Journal of the Korean institute of surface engineering
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• v.3 no.1
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• pp.7-12
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• 1970

Only mannitol or glycerine is generally used for the determination of boric acid in a nickel plating solution in order to make its acidic property so strong that it can be titrated with NaOH. However, these solutions give very amgiguous color change of indicator due to the precipitation of nickel salts . Therefore, only experienced dchemistsorwell trained workimen can accurately confirm the actual end point of the titratiion. For eliminating such interference of nickel salts and easily confirming the end point by any persons , the author attempted to find out a solution which produces no precipitates during the titration in these experiments, and also he tried to funish the reason for ambiguousness in titration. The following results were obtained after many experiments. (1) In any titrations which produce nickel salts such nI(oh)$_2$, the salt is formed umption very approximate to the end point, which shows some error by the consumption of titrant(NaOH) . Then, the pink color of phenolphthalein is absorbed by Ni(OH)$_2$ and the pH jumping at the end pint is also diminished to as little as less than 15% of the total phenophthalein ph range. (2) Known methods by complex salts of citrate,w hich do not produce precipitates of Ni(OH)$_2$, are also not very satisfactory, because, the pH jumping at the end point is only about 35% and the color change of phenolphthalein is form blue-green to purple-blue. (3) New method by complex salts of oxalate were attempted in these experiments. They also did not produce precipitates of Ni(OH)$_2$ and were very satisfactory in color change at the end of point was about 65% and the color change was from blue-green to purpled. In this methods, analytica cost was minimized by the use of less amounts of cheaper chemicals than the conventional citrates complex methods. The mixture of chemicals used was composed methods. The mixture of chemical used was composed of 37g/ι of sodium oxalate(Na$_2$C$_2$O$_4$$.$5H$_2$O), 2g/ι of phenolphthalein, and 400ml /ι of glycerin. The accuracy of analysis was within the error of 0.5%. (4) The procedure of analysis was as follows. One ml of nickel plating solution was taken out and to it were added 20ml of water and 20 ml of the above mixture for the indicator. The solution was titrated with 0.1N NaOH. The quantity of boric acid was calculated by the following equation. Boric acid (g/ι) = 6.184${\times}$F${\times}$ml .

• Carbon letters
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• v.14 no.4
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• pp.243-246
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• 2013

In this work, electroless Ni-plating on polyethylene terephthalate (PET) ultra-fine fibers surfaces was carried out to improve the electric conductivity of the fiber. The surface properties of PET ultra-fine fibers were characterized using scanning electron microscopy, X-ray diffraction, and contact angle analyses. The electric conductivity of the fibers was measured using a 4-point testing method. The experimental results revealed the presence of island-like nickel clusters on the PET ultra-fine fibers surfaces in the initial plating state, and the electric conductivity of the Ni-plated fibers was enhanced with increasing plating time and thickness of the Ni-layers on the PET ultra-fine fibers.

• Journal of the Korean institute of surface engineering
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• v.24 no.4
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• pp.206-214
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• 1991

In the basic study of selective electroless Ni plating of Si wafers, plating rate and physical properties are investigated to obtain optimum conditions of contact hole filling. Si wafers are excellently activated in the concentration of 0.5M IF, 1mM PdCl2, 2mM EDTA at $70^{\circ}C$, 90sec. The optimum condition of Ni-B deposition on p-type Si wafers is 0.1M NiSO4, 0.11M Citrate, $70^{\circ}C$, pH6.8, 8mM DMAB. The main factor in the sheet resistences variation of films is amorphous and on heat treating matrix was transformed into a stable phase (Ni+Ni3B) at $300-400^{\circ}C$. But pH or DMAB concentration in the plating solution doesn't play role of heat-affected phase change.

• Polymer(Korea)
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• v.24 no.5
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• pp.721-727
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• 2000

The electrolytic plating of a metallic nickel on carbon fiber surfaces was carried out to improve mechanical interfacial properties of carbon fiber/epoxy resin composites. The surface characteristics of carbon fibers and the mechanical interfacial properties of final composites were characterized by X-ray photoelectron spectroscopy (XPS) and interlaminar shear strength (ILSS), respectively. It was found that the electrolytic Ni-plating conditions significantly affected the degree of adhesion at interfaces between carbon fibers and epoxy resin matrix in a composite system. Especially, the increase of O,$_{1s}$/$C_{1s}$ ratio, production of NiO groups, and formation of metallic nickel on the nickel-plated carbon fiber surfaces led to an increase of the ILSS of the composites. Also, the ILSS of the composites was greatly correlated with the $O_{1s}$/$C_{1s}$ ratio of the carbon fibers treated in this work.is work.

• Journal of the Korean institute of surface engineering
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• v.35 no.5
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• pp.295-304
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• 2002

In this study, the effect of the diameter and the number of barrel hole on the total area of barrel hole were calculated and analyzed. And the effects of applied current density, rotational speed of the barrel, size and number of barrel hole, and the volume of plating materials on the distribution of plating thickness were experimented and discussed by the barrel electroplating of the tube type brass specimens in a sulfamate nickel barrel solution. The effect of barrel hole size and barrel hole area on the throwing power was also discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 1998.03a
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• pp.262-265
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• 1998

Nickel Plating improves on the corrosion resistance of materials in acid and moisture environment. In this study, we investigated the surface morphology, XRD patterns and pole figures of the various types of Ni electrodeposits. The texture of Ni electrodeposits changed from <100> to <111> through <110> with increasing the temperature of electrolyte and the concentration of nickel ion. The texture of Ni electrodeposits changed from <100> to <100> after annealing. Also the <110> texture changed to the <√310> texture after annealing.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.184-187
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• 2006

Nickel was plated electrolessly on 304L stainless steel powder. To obtain uniform coating and dispension of powder, the bath was continuously agitated with magnetic stirrer. The various pH and bath temperatures were studied. The conditions were in the range of $pH4{\sim}10$ and $45{\sim}65^{\circ}C$, respectively. The coating morphologies were examined by SEM/EDS tests. The optimum condition was pH9 at $55^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.29 no.2
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• pp.100-108
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• 1996

The internal stress of acidic electroless nickel deposits on zincated aluminum was determined by spiral contractometer. Several plating conditions such as inhibitor and complexing agent concentrations and pH affecting the internal stress were studied. The resulting intrinsic stress contribution to the total stress was discussed in terms of phosphorous content of the deposit, solution pH, and surface morphology. However, the most important was found to be thermal stress for the total stress of Al substrate, because of high thermal expansion coefficient of the aluminum substrate.

• Journal of the Korean institute of surface engineering
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• v.37 no.6
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• pp.326-334
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• 2004

Deposit charateristics of Electroless nickel(EN) were investigated with various complexing agents. As expected, the deposition rate of nickel is increased with pH and that of Phosphorous is decreased with pH. The result of SEM investigation shows that the rough surface crystallization is appeared with pH. It is show that the surface resistance of EN deposit is decreased with pH at 85$^{\circ}C$.

• Polymer(Korea)
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• v.25 no.2
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• pp.218-225
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• 2001

The electroless plating of a metallic nickel on PAN-based carbon fiber surfaces was carried out to improve mechanical interfacial properties of the carbon fiber/epoxy resin composites which were unidirectionally fabricated by a prepregging method. In this work, the influence of Ni-P alloy concentration showing brittle-to-ductile transition was investigated on interlaminar shear strength (ILSS) and impact strength of the composites. The surface properties of carbon fibers were also measured by X-ray photoelectron spectroscopy (XPS). As the result, the $O_{ls}$ /$O_{ls}$ ratio or Ni and P amounts were increased with increasing electroless nickel plating time but the ILSS were not significantly improved. However, the impact properties was significantly improved in the presence of Ni-P alloy in the carbon fiber surface, resulting in an increase of the ductility of the composites.