• Transactions on Electrical and Electronic Materials
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• v.8 no.6
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• pp.246-249
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• 2007

A triple-band antenna was developed and fabricated by LDS(Laser Direct Structuring) process. The effects of the plating rate and heat treatment condition were investigated and the gains of fabricated antennas were measured at various frequencies. The laser irradiated surface shows clearly that there are prominence and depression. It shows anchoring effect between a plating material and ablation surface. The plating rate was decreased when the plating material is exhausted in the solution. This solution needs to refreshed by the new aid solution. The copper plating thickness is decreased with the increase of heat treatment temperature in the same time but it does not change other condition. The gain of LDS antenna showed higher than the generally processed antenna. This result was related with practical use of the dimension and effective dielectric constant.

• Journal of the Korean institute of surface engineering
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• v.36 no.5
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• pp.393-397
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• 2003

The effects of the composition and additives on the blackening and deposition rate of electroless Ni-Zn plating have been examined. Hydrazine resulted in lower sheet resistance of the deposit than sodium hypophosphite. Zinc concentration more than 15 wt% and small amount of ammonium sulfate in the deposits were needed in obtaining Ni-Zn deposit with a black color. An optimum condition was obtained for the black Ni-Zn deposit at an appreciable deposition rate.

• Journal of the Korean institute of surface engineering
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• v.26 no.5
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• pp.263-270
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• 1993

The effects of surfactants on electorless copper plating bath for PCB was studied. Basic bath composition was cuplic sulfate 10g/l, EDTA.2Na 40 g/l, formalin$ 3m\ell$/l and sodium hydroxide solution for pH adjust. After addition of accelerators, stabilizers and surfactants, the polarization curves in plating bath were carried out for presumption of the plating rate. From the plating rate in bath with the various concentration of additives, the optimum condition for manufacturing the electroless copper plating bath was confirmed. It was found that the addition of $\alpha$.$\alpha$'-dipyridyl, pyridine and polyxyethylene octylphenylether was good as stabilizer, accelerator and surfactants, respectively. With this additives, the maximum plating rate of $12\mu\textrm{m}$/h at $65^{\circ}C$ and $2\mu\textrm{m}$/h at $25^{\circ}C$ was obtained.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 1999.10a
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• pp.15-15
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• 1999

In chip plating, several parameters must be taken into consideration. Current density, solution concentration, pH, solution temperature, components volume, chip and media ratio, barrel geometrical shape were most likely found to have an effect to the process yields. The 3 types of barrels utilized in chip plating industry are the conventional rotating barrel. vibrational barrel (vibarrel), and the centrifugal type. Conventional rotating barrel is a close type and is commonly used. The components inside the barrel are circulated by the barrel's rotation at a horizontal axis. Process yield has known to have higher thickness deviation. The vibrational barrel is an open type which offers a wide exposure to electrolyte resulting to a stable thickness deviation. It rotates in a vertical axis coupled with multi-vibration action to facilitate mixed up and easy transportation of components, The centrifugal barrel has its plated work centrifugally compacted against the cathode ring for superior electrical contact with simultaneous rotary motion. This experiment has determined the effect of barrel vibration intensity to the plating thickness distribution. The procedures carried out in the experiment involved the overall plating process., cleaning, rinse, Nickel plating, Tin-Lead plating. Plating time was adjusted to meet the required specification. All other parameters were maintained constant. Two trials were performed to confirm the consistency of the result. The thickness data of the experiment conducted showed that the average mean value obtained from higher vibrational intensity is nearer to the standard mean. The distribution curve shown has a narrower specification limits and it has a reduced variation around the target value, Generally, intensity control in vi-barrel facilitates mixed up and easy transportation of components, However, it is desirable to maintain an optimum vibration intensity to prevent solution intrusion into the chips' internal electrode. A cathodic reaction can occur in the interface of the external and internal electrode. $2HD{\;}+{\;}e{\;}{\rightarrow}20H{\;}+{\;}H_2$ Hydrogen can penetrate into the body and create pressure which can cause cracks. At high intensity, the chip's motion becomes stronger, its contact between each other is delayed and so plating action is being controlled. However, the strong impact created by its collision can damage the external electrode's structure thereby resulting to bad plating condition. 1 lot of chip was divided into two equal partion. Each portion was loaded to the same barrel one after the other. Nickel plating and tin-lead plating was performed in the same station. Portion A maintained the normal barrel vibration intensity and portion B vibration intensity was increased two steps higher. All other parameters, current, solution condition were maintained constant. Generally, plating method find procedures were carried out in a best way to maintained the best plating condition. After plating, samples were taken out from each portion. molded and polished. Plating thickness was investigated for both. To check consistency of results. 2nd trial was done now using different lot of another characteristics.

• Journal of Welding and Joining
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• v.14 no.3
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• pp.66-74
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• 1996

In this study, friction and wear properties of flame sprayed specimens and hard Cr plating specimens were tested, and their properties were compared each other in dry and lubrication condition. Ni-Cr powder and steel powder were used as the spray powder and sprayed on the steel(S45C) substrate by flame sprayed method. Each wear surface was observed with SEM after friction and wear test. The friction coefficient of the as-forged steel specimens was the highest among surface treatment specimens, and the other specimens appeared in order as follows ; hard Cr-plating specimens, Ni-Cr powder sprayed specimens, steel powder sprayed specimens. Comparing the wear volumes in dry condition, as forged steel specimens appeared the greatest wear volume, and the other specimens appeared wear volume in order as follows ; Ni-Cr powder sprayed specimens, steel powder sprayed specimens, hard Cr plating specimens. In friction and wear test, the hard Cr plating specimens were worn by the abrasive phenomenon, involving the cracks. The wear volume of steel powder sprayed specimens was lower than that of Ni-Cr powder sprayed specimens. Comparing the tensile strength of both sprayed coating layers, the steel powder sprayed coating layer was better than Ni-Cr powder sprayed coating layer.

• Journal of the Korean institute of surface engineering
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• v.14 no.4
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• pp.215-220
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• 1981

The surface appearance of chromium electrodeposit was studied by employing a pulse curr-ent plating in self-regulating high speed (SRHS) bath containing 20 g/$\ell$, K2SiF6 7.5 g/$\ell$ SrSO4 and 250 g/$\ell$ CrO3. As the pulse frequency increased, the surface appearance changed suddenly from bright a-ppearance in a direct current plating condition to gray one in the range of pulse frequency less than about 20KHz. However the bright appearance is recovered as the pulse frequen-cy exceeded 20 KHz. This phenomena seemed to be related with the preferred orientation of electrodeposits, considering the relationship between the preferred orientation of elect-rodeposits and surface appearance in a SRHS bath. Direct current plating was also applied to both Sargent and SRHS bath and investigat-ion on surface appearance was extended to the high current density of 400 A/dm2. In a Sa-rgent bath, the increase in bath temperature was necessary for bright appearance as the current density was increased within 150 A/dm2, but bright region was shown in the cons-tant temperature of 70-75$^{\circ}C$ above the current density of 150A/dm2. On the other hand, two regions of surface brightness was found in a SRHS bath. One is region in the low temperature less than 25$^{\circ}C$ and the other in the moderate temperature range from 55$^{\circ}C$ to 65$^{\circ}C$.

• Journal of the Korean institute of surface engineering
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• v.18 no.3
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• pp.105-115
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• 1985

Lead-tin-copper ternary alloy electrodeposition is conducted onto the inner bore surface of plain bearings as an overlay in order to investigate the effect of slot width, current density and fluoboric acid concentration on the uniformity of overlay. The thickness of overlay is analyzed by means of current distribution resulting from the overvoltage of plating bath and the apparent distance between cathode and anode. The result demonstrate that the uniformity of overlay is remarkably dependent of the slot size and current density, but has little bearing on the fluoboric acid concentration over 100g/L. This present study indicates that uniform overlay is obtainable within the tolerable thickness of ${\pm}2{\mu}m$ by using the slot width of 22mm. The surface morphology examination also shows the important role of concentration polarization of the micro-uniformity of overlay. The micro-uniformity has improved at the low concentration polarization which resulted from operating at the low current density and high fluoboric acid concentration. The surface morphology of deposits exhibits the vivid pyramid crystalline in the plating condition of low concentration polarizatio and all deposits have columnar structure parallel to the applied electric field regardless of the electroplating condition used.

• Journal of the Korean institute of surface engineering
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• v.28 no.1
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• pp.23-33
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• 1995

AISI 304 stainless steel has high resistance to corrosion due to the presence of a self-healing chromium oxide film on the surface, which also accounts for the difficulty in plating. Surface cleaning of this alloy is of fundamental importance in gold plating since its effectiveness puts an upper limit on the quality of the final coating. The cleaning of AISI 304 stainless steel was investigated with elimination of artificial passive oxide film and degreasing of remaining buffing wax as stearic acid. The familiar cleaning methods i.e. ultrasonic cleaning, electro-cleaning and activation treatment were fabricated in this study. Activation treatment showed best cleaning efficiency for elimination of passive oxide film among these methods, which was also confirmed by AES (Auger electron spectrometer) analysis. However, the best condition of cleaning was obtained by combining these methods. Electrocleaning time, for degreasing the stearic acid layer, was decreased with increasing amount of added KCN.

• Proceedings of the Materials Research Society of Korea Conference
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• 1992.05b
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• pp.26-27
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• 1992

The effect of activation and electroless nickel plating conditions on contact properties were investigated for selective electroless nickel plating of Si farers in order to obtain an optimum condition of contact hole filling. According to RCA prosess, p-type si 1 icon (100) surface was cleaned out and activated. The effects of temperture, DMAB concentration, time, and stirring iwere investigated for activation of p-type Si(100) surface. The optimal activation condition obtained was 0.5M HF, 1mM PdCl$_2$, 2mM EDTA, 7$0^{\circ}C$, 90sec under ultrasonic vibration. In electroless nickel plating, the effect of temperature, DMAB concentration, pH, and plating ti me were studied. The optimal plating condition found was 0. 10M NiS0$_4$.$H_2O$, 0.lIM Citrate, pH 6.8, 6$0^{\circ}C$, 30 minutes. The contact resistence of fi]ms wascomparatively low. It took 30 minutes to obtain 1$\mu$m thick film with 8$\mu$M DMAB concentration. The film surface roughness was improved with increasing temperature and decreasing pH of the plating solution. The best quality of the film was obtained with the condition of temperature 6$0^{\circ}C$ and pH 6.8. The micro-victors hardness of film was about 600Hv and was decreased wi th increasing particle size of plating layer.

• Applied Chemistry for Engineering
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• v.19 no.2
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• pp.228-235
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• 2008

Nickel plating thickness increased with the electric current density, and the augmentation was more thick in $6{\sim}10A/dm^2$ than low current. Hull-cell analysis was tested to evaluate the current density. Optimum thickness was obtained at a temperature of $60^{\circ}C$, and the pH fluctuation of 3.5~4.0. Over the Nickel ion concentration of 300 g/L, plating thickness increased with the current density. The rate of decrease in nickel ion concentration was increased with the current density. The quantity of plating electro-deposition was increased at the anode surface, which was correlated with the increase of plating thickness. The plating thickness was increased because of the quick plating speed. However, the condition of the plating surface becomes irregular and the minuteness of nickel plating layer was reduced with the plating rate. After the corrosion test of 25 h, it was resulted in that maintaining low electric current density is desirable for the excellent corrosion resistance in lustered nickel plating. According to the program simulation, the thickness of diffusion layer was increased and the concentration of anode surface was lowered for the higher current densities. The concentration profile showed the regular distribution at low electric current density. The field plating process was controlled by the electric current density and the plating thickness instead of plating time for the productivity. The surface physical property of plating structure or corrosion resistance was excellent in the case of low electric current density.