• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.942-945
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• 2001

Pulse electrochemical micromachining offers significant improvements in dimensional accuracy as compared with conventional electrochemical machining. One primary issue in pulse electrochemical micromachining is to identify and control machining depth as well as interelectrode gap size. This paper presents an identification method for the machining depth by in-process analysis of machining current and interelectrode gap size. The inter electrode gap characteristics, including pulse current, effective volumetric electrochemical equivalent and electrolyte conductivity variations, are analysed based on the model and experiments.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 춘계학술대회논문집
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• pp.127-130
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• 2003

Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric, sulfuric and distilled water has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

• 소성∙가공
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• 제12권4호
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• pp.388-393
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• 2003

Electrolytic polishing is the anodic dissolution process in the transpassive state. It removes non-metallic inclusions and improves mechanical and corrosion resistance of stainless steel. Electrolytic polishing is normally used to remove a very thin layer of material from the surface of a metal object. An electrolyte of phosphoric acid 50% in vol., sulfuric acid 20% in vol. and distilled water 30% in vol. has been used in this study. In the low current density region, there can be found plateau region and material removal process and leveling process occur successively. In this study, an electrochemical polishing process using pulse current is adopted as a new electrochemical polishing process. In electrochemical machining processes, it has been found that pulse electrochemical processes provide an attractive alternative to the electrochemical processes using continuous current. Hence, this study will discuss the electrochemical polishing processes in low current density region and pulse electrochemical polishing.

• 한국생산제조학회지
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• 제21권2호
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• pp.246-251
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• 2012

Pulse electrochemical polishing process has been used to improve mechanical properties such as surface roughness and corrosion resistance on conductive metallic materials. In addition, pulse electrochemical polishing process with various frequency may produce a lustrous, smoother, deburred and cleaned surface on workpiece. The aim of this paper is to study surface characteristics of pulse electrochemical polishing for various frequency conditions using AFM to verify localized surface variation in nanometer scale.

• 한국생산제조학회지
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• 제20권4호
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• pp.395-400
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• 2011

Scanning Probe Lithography is a method to localized oxidation on single crystal silicon wafer surface. This study demonstrates nanometer scale non contact lithography process on (100) silicon (p-type) wafer surface using AFM(Atomic force microscope) apparatuses and pulse controlling methods. AFM-based experimental apparatuses are connected the DC pulse generator that supplies ultra short pulses between conductive tip and single crystal silicon wafer surface maintaining constant humidity during processes. Then ultra short pulse durations are controlled according to various experimental conditions. Non contact lithography of using ultra short pulse induces electrochemical reaction between micro-scale tip and silicon wafer surface. Various growths of oxides can be created by ultra short pulse non contact lithography modification according to various pulse durations and applied constant humidity environment.

• 한국정밀공학회지
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• 제22권5호
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• pp.37-44
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• 2005

In this paper, wire electrochemical machining (Wire ECM) with ultra short pulses is presented. Platinum wire with $10{\mu}m$ diameter was used as a tool and 304 stainless steel was locally dissolved by electrochemical machining in 0.1M $H_{2}SO_4$ electrolyte. Wire ECM can be easily applied to the fabrication of arbitrarily shaped micro-grooves without tool wear. The change of machining gap according to applied pulse voltage, pulse on-time and pulse period was investigated and the optimal pulse condition for stable machining was obtained. Using this method, various micro-grooves with less than $20{\mu}m$ width were fabricated.

• 전기학회논문지P
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• 제54권4호
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• pp.224-229
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• 2005

This paper presents a bidirectional pulse power electrochemical etching system for groove manufacturing of the dynamic bearings. To manufacture the dynamic bearing for the groove, it is very important to consider the depth and roughness. If the precision of the groove is not exact, we can not get the desirable performance for the target of the dynamic bearing. To make the groove of bearing precise, we propose the method of electrochemical etching system. In order to design the depth and roughness exactly, the bidirectional pulse power converter is proposed. With the bidirectional pulse power converter, we obtain the condition and the parameters of converter such as frequency, duty ratio, time, temperature, velocity, pressure and so on. In this paper, we get the experimental results to verify the precise groove manufacturing.

• 한국정밀공학회지
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• 제19권4호
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• pp.101-108
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• 2002

A specially-built EMM (Electrochemical Micro Machining) / PECM (Pulse Electrochemical Machining) cell, a electrode tool filled with non-conducting material, a electrolyte flow control system and a small & stable gap control unit are developed to achieve accurate dimensions of recesses. Two electrolytes, aqueous sodium nitrate and aqueous sodium chloridc arc applied in this study. The farmer electrolyte has better machine-ability than the latter one because of its appropriate changing to the transpassive state without pits on the surface of workpiece. It is easier to control the machining depth precisely by micrometer with pulse current than direct current. This paper also presents an identification method for the machining depth by in-process analysis of machining current and inter electrode gap size. The inter electrode gap characteristics, inc1uding pulse current, effective volumetric electrochemical equivalent and electrolyte conductivity variations, are analyzed based on the model and experiments.

• 한국정밀공학회지
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• 제28권2호
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• pp.251-256
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• 2011

The radial overcut in micro electrochemical machining was investigated. The prediction of overcut is important not only for the machining accuracy but also for the shape control of micro structures. In micro ECM, machining gap or overcut depends on electrolyte, pulse voltage, pulse duration and dissolution time etc. Understanding of electrochemical dissolution rate is necessary for the overcut prediction. In this paper, the radial overcut of micro electrochemical machining according to pulse duration and dissolution time was simulated using electrochemical principles and also experimentally estimated.

• Journal of Electrochemical Science and Technology
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• 제14권1호
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• pp.15-20
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• 2023

Ionic liquids are considered as a promising, alternative solvent for the electrochemical synthesis of metals because of their high thermal and chemical stability, relatively high ionic conductivity, and wide electrochemical window. In particular, their wide electrochemical window enables the electrodeposition of metals without any side reaction of electrolytes such as hydrogen evolution. The electrodeposition of silver is conducted in 1-n-butyl-3-methylimidazolium chloride ([C4mim]Cl) ionic liquid system with a silver source of AgCl. This study is the first attempt to electrodeposit silver nanoparticles without using co-solvents other than [C4mim]Cl. Pulse electrolysis is employed for the synthesis of silver nanoparticles by varying applied potentials from -3.0 V to -4.5 V (vs. Pt-quasi reference electrode) and pulse duration from 0.1 s to 0.7 s. Accordingly, the silver nanoparticles whose size ranges from 15 nm to ~100 nm are obtained. The successful preparation of silver nanoparticles is demonstrated regardless of the kinds of substrate including aluminum, stainless steel, and carbon paper in the pulse electrolysis. Finally, the antimicrobial property of electrodeposited silver nanoparticles is confirmed by an antimicrobial test using Staphylococcus aureus.