• 한국표면공학회지
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• 제36권2호
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• pp.161-167
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• 2003

In order to investigate the effects of pulse plating conditions on the electrodeposition of trivalent chromium, electroplating experiments from bath with low concentration of trivalent chromium were performed. The variation of current efficiency of chromium electroplating with the electroplating conditions was explained. The maximum current efficiency of pulse plating is 6.4 times as high as that of direct plating at the same mean current density The nodular size increased with pulse plating time and the pulse frequency.

• 한국표면공학회지
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• 제35권3호
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• pp.141-148
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• 2002

Fe-C alloy layers were produced by pulse plating and the properties were compared with those produced by D.C. plating. When the pulse on time ($T_{on}$ ) was the same, both the duty cycle and peak current density($I_{p}$ ) had little influence on the carbon content and the hardness of the layer. The structure and hardness of the direct current plating were similar to those of the pulse current plating. However, the ductility was enhanced when the pulse current was applied due to the release of residual stress during the pulse off time($T_{off}$).).

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2001년도 ICCAS
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• pp.37.1-37
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• 2001

Electric plating is used in various industry field. Specially, pulse plating is able to deposit material at high current density compared to conventional DC plating. For example, pulse plating can get more fine grain, can improve adhesion and metal distribution and current efficiency, can reduce internal stress and crack. Therefore, we developed bidirection pulse power supply(BPPS) which has high speed pulse current and high current density and improve deposition quality and increase plating speed in this paper. BPPS(Bidirection pulse power supply) needs high speed rising time, falling time and output current accuracy. BPPS consists of rectifier part, chopper part, invertor part, and control part. Rectifier part changes outprt current direction.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2000년도 전력전자학술대회 논문집
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• pp.685-688
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• 2000

Pulse plating is about to deposit material at high current density compared to conventional DC plating. For example pulse plating can get more fine grain can improve adhension and metal distribution and current efficiency can reduce internal stress and crack. therefore we studied pulsed power supply which has high current density and improve deposition quality and increase plating speed in this paper.

• 마이크로전자및패키징학회지
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• 제26권2호
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• pp.51-54
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• 2019

실리콘 기판상에 여러 조건의 전류밀도에서 로듐 도금을 실시하였다. 직류전원의 경우 전류밀도가 증가하면 로듐 표면에 균열이 발생하였다. 잔류응력을 낮추기 위하여 펄스전류를 인가하였다. 펄스전류의 off 시간이 도금층의 잔류응력을 낮추는데 영향을 주었다. 펄스전류의 인가 주기를 5:5로 하였을 경우 균열 없는 로듐 도금층을 얻었다.

• 한국표면공학회지
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• 제22권4호
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• pp.197-206
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• 1989

The Composition and throwing power-of Pb-Sn alloy deposits are investigated in tems of the pulse parameters in pulse plating. Microhardness and intermal srress of alloy deposots are measured. The current efficiency of pulse plating is lower than that of D.C.plating while cathode overpotential and macro-throwing power noticebly increase with increasing peak current density. The Pb content of P.C. plated alloy deposits with increasing average current density, is relatively lower than of D.C. plated deposits at the same average current density. The internal stress of Pb-Sn alloy is not detected and the microhardness are 9.0kg/mm2 and 11kg/mm2 for D.C. plated P.C. plated deposits, respectively.

• 한국표면공학회지
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• 제14권4호
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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$^{\circ}C$.

• 한국표면공학회지
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• 제30권2호
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• pp.104-110
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• 1997

Conventional hexavlent chromium electroplating baths deposit the matal at low cathode efficiency and have poor covering and throwing power. The processs also generate hazardous wastes. To overcome many of the disadvantages of hexavalent chromium plating the use of trivalent chromium has advocted. After Yoshida, who first studied trivalent chromium plating, using ammonium sulfate and urea, there are numerous report describing the trivalent chromium electropating process using complexing agents. This study investigaten trivalent chromium plating electrolyte solutious containing formate as a complexing agent and ammouim chloride for conducting agent. The effects of composition and operating conditions on deposits and current efficiencies were investigated in trivalent chromium plating baths by analyzing the relationship pulse conditions and surface morphology The surface morphology of the deposits was observed by SEM. pulse electrolysis has been effective on obtaining a smooth with high current efficiency comparing with D.C. electrolysis in trivalent chromium solution.

• 한국표면공학회지
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• 제35권1호
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• pp.17-32
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• 2002

Electroplating methods by molten salts and non-aqueous melts were employed for aluminium coating on STS 316L stainless steel. After coated with Ni or non-coated surface on stainless steel, Al pulse plating was carried out in two different types of electrolytes at room temperature. The Al layer from $AlCl_3$-TMPAC melts could not obtain appreciable thickness for engineering application due to chemical reactions between deposits and moisture of air. However, The Al coating by pulse plating in the Ethylbenzene-Toluene-$AlBr_3$ systems was found to be solid coating layer with a few $\mu\textrm{m}$ scale. The conductivity of Ethylbenzene-Toluene-$AlBr_3$ electrolyte was as functions of time and agitation. By seven days exposure after mixing of the electrolyte, Al-deposited layer shows uniform and near by pore-free with high current density (higher than 30mA/$\textrm{cm}^2$). The roughness and imperfection of coating layer were decreased with a increasing agitation speed. It was found that the optimum condition for the Al pulse plating on the 316L stainless steel was a 400mA peak current, duty cycle, $t_{on}$ $t_{ off}$=3ms/1ms, and a current density of 30mA/$\textrm{cm}^2$.

• 마이크로전자및패키징학회지
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• 제14권3호
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• pp.51-55
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• 2007

Ni-Fe 전해도금 시 전류밀도, 펄스주기와 전류인가 방식, 도금욕의 Fe 이온의 농도, 첨가제 등의 인자들이 도금 층의 조성, 표면형상, 표면 경도에 미치는 영향에 관하여 연구하였다. 시편에 가해지는 전류밀도, 전류인가방식과 Fe이온의 농도를 변화시킴으로써 Ni-Fe의 도금 층 내에 Ni-Fe의 조성을 조절하는 것이 가능하였고 또한 첨가제의 양을 변화시킴으로써 표면형상이 변화됨을 확인하였다. PC를 사용한 경우 직류를 사용한 경우보다 높은 $550{\sim}600Hv$의 경도값을 얻을 수 있었다. 사카린을 첨가한 경우 도금층의 잔류응력을 낮추어 균열이 없는 도금층을 얻었다. Ni-Fe의 단면의 조성을 분석함으로써 도금 층의 두께에 따른 조성의 변화를 확인하였다.