• Transactions of the Korean Society of Automotive Engineers
• /
• v.22 no.4
• /
• pp.30-35
• /
• 2014

According to weight lightning trend of automobile body, necessity of resistance spot welding (RSW) of Mg alloy on automobile industry is increasing rapidly because of the highest specific strength among commercial metals. Mg alloy has low electric resistance and high thermal conductivity like as Al alloy, so that needs applying high current in short time when welding. Thick oxide film of Mg alloy pollutes the electrodes and makes partial current carrying paths when on welding. Partial current carrying paths signify excessive concentration of current. There can initiate expulsion easily and reduces electrode life rapidly. Generating partial current carrying paths and expulsions are influenced by shapes of electrode. Therefore, electrode life also influenced by shape. In this study, we perform life test of RSW electrode of radius type. Measure tensile shear load and nugget size every spot alternately. As a result, radius type electrode can extend life over twice as dome type electrode.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.02a
• /
• pp.115-115
• /
• 2012

반도체/디스플레이 산업분야의 발전으로 진공 공정 기술력 또한 증진되고 있다. 반도체소자의 초미세화, 진공부품의 대면적화가 진행 되면서 진공 공정 중에 발생하는 오염입자를 제어하는 것이 이슈가 되고 있다. 오염입자는 플라즈마의 물리적인 부식과 활성이 높은 화학반응에 의해 진공부품에서 부식이 진행되어 발생하며, 이는 반도체 및 디스플레이 부품의 신뢰성측면과 수율저하 등 life time의 근본적인 문제점으로 대두되고 있다. 본 연구에서는 반도체/디스플레이 장비용 코팅부품으로 많이 사용되고 있는 Al2O3 코팅막을 이용하였으며, sealing time에 따른 Anodic Aluminum Oxide (AAO) electrode의 물성특성평가 및 진공평가기술을 이용하여 life time을 예측하는 연구를 수행하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
• /
• 2004.05a
• /
• pp.149-154
• /
• 2004

In this paper, we observed an electrode structure that is an important element that decide life of compact fluorescent lamp. We measured winding and application type of electron emission material and electrode damage with SEM(Scanning Electron Microscope). From now on, we need to measure rather several difference aging-time sample than analyze a relation electrode between life

• Journal of Welding and Joining
• /
• v.31 no.3
• /
• pp.49-53
• /
• 2013

Recently, studies about application of magnesium alloy sheet to automotive bodies are on the increase. For application to automotive bodies, researches about characteristics of resistance spot welding of magnesium alloy sheet are essential. Electrode life of resistance spot welding of magnesium alloy is very short due to sticking of magnesium alloy to copper alloy electrode. To increase electrode life, most effective method is inserting cover plate between electrode and magnesium sheet. But application of cover plate to actual process is difficult and decreases welding productivity. Process tape supplied automatically as cover plate can minimize lose of productivity and increase welding quality. In this study, resistance spot welding of magnesium alloy is carried out with applying process tape. Acceptable welding current region according to electrode force and welding time is determined.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.10a
• /
• pp.43-46
• /
• 2003

To develop bevel gear dies that have characteristics of high precision and enough life time, the technology of die manufacturing and design which increase the resistance of wear and fatigue is essentially needed. Here in the study, we have investigated several materials for dies and electrode. And, the most economical and suitable electrode material has been selected through the characteristic analysis of electrode materials such as copper, graphite and chromium copper. With the help of CAD/CAM/CAE, the total manufacturing system of high precision electrode for bevel gear has been established.

• Journal of Welding and Joining
• /
• v.33 no.2
• /
• pp.47-55
• /
• 2015

With using adaptive control of the resistance spot welding machine, the advantage on electrode life time for galvanized steels has been addressed. This study was aimed to evaluate the electrode life time of galvanized steels with applying the constant current control and the adaptive control resistance spot welding process for a comparison purpose. The growth in diameter of electrode face was similar for both the constant current and the adaptive control up to 2000 welds. The button diameter was decreased with weld numbers, however, sudden increase in button diameter with use of the adaptive control after 1500 welds was observed. The peak load was continuously decreased with increasing number of welds for both the constant current and the adaptive control. The current compensation during a weld was observed with using the adaptive control after 1800 welds since the ${\beta}$-peak on dynamic resistance curve was detected at later weld time. The current compensation with adaptive control during resistance spot welding enhanced the nugget diameter at the faying interface of steel sheets and improved the penetration to thinner steel sheet.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.07a
• /
• pp.441-443
• /
• 2005

According as CCFL(Cold Cathode Fluorescent lamp) of light source in Backlight unit for Note PC (Personal computer) is presently needed to low power consumption and long life time, the development focus of CCFL is going on the discharge gas, phosphor and electrode material. First of all, discharge voltage characteristic of CCFL is closely connected with electrode material For low discharge voltage, the characteristic of electrode material is needed to low work function, low sputtering ratio and superior manufacturing property. We developed new CCFL with Nb/Ni Clad electrode superior to conventional CCFL. Because Nb/Ni Clad electrode with Ni material and Nb material, the electrical characteristic is superior to other electrode materials. The electrode of Nb/Ni Clad is composed that Ni of outside material has superior manufacturing property and Nb of inside material has low work function. Nb/Ni Clad of new electrode material is made by process of Rolling mill at high pressure and heat treatment. We compared electrical characteristic of Nb/Ni clad electrode with conventional Mo electrode by measurement. Mo electrode and Nb/Ni Clad electrode of cup type with diameter 1.1 mm and length 3.0mm are used to this experiment. Material content of Mo electrode is Mo 100%. But, Nb/Ni Clad electrode is composed by content of Nb 40% and Ni 60%. The result of comparison measurement between new CCFL with Nb/Ni Clad electrode and conventional CCFL was appeared that CCFL with Nb/Ni Clad electrode had superior characteristic than conventional CCFL. As a result of experiment, we completed Note PC with low power consumption and long life time by application of new CCFL with Nb/Ni Clad electrode.

• Journal of Biosystems Engineering
• /
• v.41 no.2
• /
• pp.75-84
• /
• 2016

Purpose: In-situ water quality monitoring based on ion-selective electrodes (ISEs) is a promising technique because ISEs can be used directly in the medium to be tested, have a compact size, and are inexpensive. However, signal drift can be a major concern with on-line management systems because continuous immersion of the ISEs in water causes electrode degradation, affecting the stability, repeatability, and selectivity over time. In this study, a computer-based nitrate monitoring system including automatic electrode rinsing and calibration was developed to measure the nitrate concentration in water samples in real-time. Methods: The capabilities of two different types of poly(vinyl chloride) membrane-based ISEs, an electrode with a liquid filling and a carbon paste-based solid state electrode, were used in the monitoring system and evaluated on their sensitivities, selectivities, and durabilities. A feasibility test for the continuous detection of nitrate ions in water using the developed system was conducted using water samples obtained from various water sources. Results: Both prepared ISEs were capable of detecting low concentrations of nitrate in solution, i.e., 0.7 mg/L $NO_3-N$. Furthermore, the electrodes have the same order of selectivity for nitrate: $NO_3{^-}{\gg}HCO_3{^-}$ > $Cl^-$ > $H_2PO_4{^-}$ > $SO{_4}^{2-}$, and maintain their sensitivity by > 40 mV/decade over a period of 90 days. Conclusions: The use of an automated ISE-based nitrate measurement system that includes automatic electrode rinsing and two-point normalization proved to be feasible in measuring $NO_3-N$ in water samples obtained from different water sources. A one-to-one relationship between the levels of $NO_3-N$ measured with the ISEs and standard analytical instruments was obtained.

• Korean Journal of Materials Research
• /
• v.27 no.3
• /
• pp.137-143
• /
• 2017

Boron-doped diamond (BDD) electrode has an extremely wide potential window in aqueous and non-aqueous electrolytes, very low and stable background current and high resistance to surface fouling due to weak adsorption. These features endow the BDD electrode with potentially wide electrochemical applications, in such areas as wastewater treatment, electrosynthesis and electrochemical sensors. In this study, the characteristics of the BDD electrode were examined by scanning electron microscopy (SEM) and evaluated by accelerated life test. The effects of manufacturing conditions on the BDD electrode were determined and remedies for negative effects were noted in order to improve the electrode lifetime in wastewater treatment. The lifetime of the BDD electrode was influenced by manufacturing conditions, such as surface roughness, seeding method and rate of introduction of gases into the reaction chamber. The results of this study showed that BDD electrodes manufactured using sanding media of different sizes resulted in the most effective electrode lifetime when the particle size of alumina used was from $75{\sim}106{\mu}m$ (#150). Ultrasonic treatment was found to be more effective than polishing treatment in the test of seeding processes. In addition to this, BDD electrodes manufactured by introducing gases at different rates resulted in the most effective electrode lifetime when the introduced gas had a composition of hydrogen gas 94.5 vol.% carbon source gas 1.6 vol.% and boron source gas 3.9 vol.%.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.6
• /
• pp.291-298
• /
• 2016

Electrochemical water treatment process as a useful treatment method for the removal of non-degradable matter has been consistently studied for several decades. Key process of electrochemical water treatment are oxidation reaction from an anode and reduction from a cathode. In this study, the effect of pre-treatment methods in the insoluble electrode manufacturing process for the water treatment has been evaluated for the life time of electrode The results of this study showed that pre-treatment methods of a base metal such as surface roughness, clean method and interlayer formation influenced to life time of electrode when the same condition (catalyst electrode layer coating method and material system) was applied for pre-treatment methods. This study was conducted by using $IrO_2/Ti$ electrode In the test of sand-blasting process, an electrode manufactured by using sanding media of different sizes resulted in the most effective electrode life time when the size of alumina was used for $212{\sim}180{\mu}m$ praticle size (#80). The most effective method was considered using arc plasma in the additional roughness control and cleaning process, sputtering method to form Ta type interlayer formation process.