• Journal of the Korean institute of surface engineering
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• v.32 no.3
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• pp.219-223
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• 1999

A new additive for semi-brightness finish in nickel electroplating, having a quarternary ammonium salt structure, has been developed in this study. The effectiveness of the new additive was tested in laboratory-scale eletroplating tests as well as in a full-scale factory plating line. An examination of the plated surface showed that the new additive is as good as the one produced by the most commonly used additive in the nickel plating industry. The plated surface was examined by SEM, EPMA, and Reflectance Spectroscopy, and was found to be compatible to the one obtained with commercial additives. The new additive has a shelf life comparable with those of other commercially available additives. The additive developed in this study has an excellent potential to be used commercially.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2003.11a
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• pp.106-109
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• 2003

With the variation of Ag concentration in bath, current density, additive and agitation for electroplating of Sn-Ag solder, the compositions and the morphologies of solder were studied. It was possible to control Ag content in Sn-Ag solder by varying Ag concentration in bath and current density The microstructure size of Sn-Ag solder decreased with increasing current density. Duty cycle of pulse electroplating and quantity of additive affected on Ag content of deposit and surface roughness. In this work eutectic Sn-Ag solder bumps with fine pitch of 30m and height of 15m was formed successfully. The Ag content of electrodeposited solder was confirmed by EDS and WDS analyses and the surface morphologies was analyzed by SEM and 3D surface analyzer.

• Journal of the Korean institute of surface engineering
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• v.12 no.3
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• pp.174-179
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• 1979

The effects of brightness, electrochemical behaviour on the organic additives, such as aldehydes, polymers, amines and condensed product obtained from epichlorohydrin and nicotinamide, in cyanide zinc electrolplating bath have been studied by controlled potential electrolyser. The results were summerized as follows: (1) It was found that the addition of only one compound of these organic compounds in the bath was unsuitable but mixture of anisaldehyde or monoethanolamine and condensed product as suitable as brightener. (2) The cathodic polarization curve of polymers or aldehydes in cyanide zinc electroplating bath was almost the same but the cathodic polarization curve of condensed product remarkable shifted to noble potential more than non-additive curve.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.379-385
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• 2003

The surface morphology, the glossiness and the hardness of Zn-Cr and Zn-Cr-X(X:Co, Mn) alloy electrodeposits were investigated by using chloride bath with EDTA additive and flow cell system. The surface morphology of Zn-Cr alloy and Zn-Cr-Mn alloy changed from fine needle shape crystalline structure to colony structure of fine granular crystallites with increasing current density in the range of 20-100 $A/dm^2$. The surface morphology of Zn-Cr-Co alloy deposited from low Co concentration bath(2.5-10 g/$\ell$) was similar to that of Zn-Cr alloy, while that of Zn-Cr-Co alloy deposited from high cobalt concentration bath was fine granular crystalline structure in the same range of current density. The glossiness of Zn-Cr and Zn-Cr-Mn alloy increased noticeably with increasing current density, while that of Zn-Cr-Mn alloy decreased with increasing Mn concentration of bath in high current density region. The glossiness of Zn-Cr-Co alloy deposited from low Co concentration bath increased with current density while that of the alloy from high Co concentration bath decreased with increasing current density. The hardness of Zn-Cr and Zn-Cr-X alloy increased noticeably with current density.

• Journal of the Korean institute of surface engineering
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• v.25 no.4
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• pp.181-186
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• 1992

To investigate how to produce the crack free and chromium deposits, bath compositions, additives, electrolysis conditions and other electroplating parameters, such as cathodic current efficiency, surface hard-ness, crack density and corrosion rate of deposits were examined carefully. The crack free chrome deposits were well obtained using both wetting agents and two kind of additives. At 60 A/d$\m^2$, $60^{\circ}C$ electrolysis condition, crack free bright hard chromium deposits were well obtained to a thickness $300\mu\textrm{m}$ in Additive-I and Additive-II added solution.

• Journal of the Korean institute of surface engineering
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• v.13 no.1
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• pp.3-7
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• 1980

The crystalline structure and leveling action on the deposit of zinc from the cyanide zinc electroplating bath containing organic additives, such as aldehydes, polymers, amines and condensed product, have been studied by microscope and X-ray diffraction methods. The crystalline structure of the deposit from the bath containing no-additive, polymers and aldehydes appeared very strong orientation on (101) plane and the surface was rough, while from condensed product having remarkable effects in brightness appeared very strong orientation on (110) and the crystallinity was very fine. In the leveling action, the effect of any additives except reaction product was not appreciable, whereas the effect of the reaction product obtained remarkably excellent result.

• Journal of Power System Engineering
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• v.5 no.2
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• pp.71-78
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• 2001

Using sodium hypophosphite as reducing agent, bath composition and plating condition of electroless copper plating on plating rate have been studied. The followings were determined as optimum, bath composition; $CuSO_4\;0.025M,\;NiSO_4\;0.002M,\;NaH_2PO_2\;0.4M$, sodium citrate 0.06M, $H_3BO_3$ 0.6M, thiourea or 2-MBT $0.2mg/{\ell}$, and operation conditions; pH $9{\sim}10$ at bath temperature rage of $60{\sim}70^{\circ}C$. A small amount of nickel ion($Ni^{2+}/Cu^{2+}$=0.002/0.025) to the hypophosphite reduced solution promotes autocatalysis and continuous plating. An additive such as thiourea or 2-MBT of a small amount($0.2mg/{\ell}$) can be used to stabilize the solution without changing plating rate much. The attivation energy between $20^{\circ}C\;and\;70^{\circ}C$ were calculated to be 11.3kcal/mol for deposition weight. Plating reaction had been ceased by the adjustment of pH above 13, temperature higher than $90^{\circ}C\;and\;under\;20^{\circ}C$. Deposited surface became worse in the case of increment of bath temperature above $80^{\circ}C$.

• Journal of the Microelectronics and Packaging Society
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• v.10 no.4
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• pp.73-79
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• 2003

With the variation of Ag concentration in bath, current density, duty cycle, additive and agitation for electroplating of Sn-Ag solder, the compositions and the morphologies of solder were studied. It was possible to controll Ag content in Sn-Ag solder by varying Ag concentration in bath and current density. The microstructure size of Sn-Ag solder decreased with increasing current density. Duty cycle of pulse electroplating and quantity of additive affected on Ag content of deposit and surface roughness. In this work eutectic Sn-Ag solder bumps with fine pitch of 30 $\mu\textrm{m}$ and height of 15 $\mu\textrm{m}$ was formed successfully. The Ag content of electrodeposited solder was confirmed by EDS and WDS analyses and the surface morphologies was analyzed by SEM and 3D surface analyzer.

• Membrane and Water Treatment
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• v.5 no.2
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• pp.109-122
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• 2014

Polyvinylidene fluoride (PVDF) hollow fiber membrane is widely used for water treatment. However, the weak mechanical strength of PVDF limits its application. To enhance its tensile strength, a double-layer composite hollow fiber membrane, with PVDF and polyetherimide as the external and inner layers, respectively, was successfully prepared through phase inversion technique. The effects of additive content, air gap distance, N,N-dimethyl-acetamide content in the inner core liquid, and the temperature of external coagulation bath on the membrane structure, permeation flux, rejection, tensile strength, and porosity were determined. Experimental results showed that the optimum preparation conditions for the double-layer composite hollow fiber membrane were as follows: PEG-400 and PEG-600, 5 wt%; air gap distance, 10 cm; inner core liquid and the external coagulation bath should be water; and temperature of the external coagulation bath, 40 C. A single layer PVDF hollow fiber membrane (without PEI layer) was also prepared under optimum conditions. The double-layer composite membrane remarkably improved the tensile strength compared with the single-layer PVDF hollow fiber membrane. The permeation flux, rejection, and porosity were also slightly enhanced. High-tensile strength hollow fiber PVDF ultrafiltration membrane can be fabricated using the proposed technique.

• Journal of the Korean institute of surface engineering
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• v.30 no.2
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• pp.128-135
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• 1997

The effect of the polyethyledglycol(PEG) on the surface morphology and crystal orientation of electrodeposited zinc from a chloride (1.5M Zinc+7.0M chloriode) have been studied by means of electrochemical methodes, scanning electron microscopy, surface appearance measurement and X-ray diffraction patterns. The resistance of electrodeposit increased, whereas the evolution of hydrogen decreased with incrasing of molecular weight of the PEG. Large grains of electrodeposit were obtained from bath in the absence of organid additive. When the PEG was added, fine grained crystals were observed and the surface roughness was relatively small, but surface appearance deteriorated. The preferred orientation with a(101) plane parallel to the surface was obtained from the PEG addited bath.