• Resources Recycling
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• v.15 no.4 s.72
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• pp.44-51
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• 2006

Most electric arc furnace dust (EAFD) treatment processes to recover zinc from EAFD employ carbon as a reducing agent for the zinc oxide in the EAFD. In the present work, the reduction reaction of zinc oxide with carbon in the present of iron oxide was kinetically studied. The experiments were carried out at temperatures between 1173 K and 1373 K under nitrogen atmosphere using a weight-loss technique. From the experimental results, it was concluded that adding the proper amount of iron oxide to the reactant accelerates the reaction rate of zinc oxide with carbon. This is because iron oxide in the reduction reaction of zinc oxide with carbon promotes the carbon gasification reaction. The spherical shrinking core model for a surface chemical reaction control was found to be useful in describing kinetics of the reaction over the entire temperature range. The reaction has an activation energy of 53 kcal/mol (224 kJ/mol) for ZnO-C reaction system, an activation energy of 42 kcal/mol (175 kJ/mol) for $ZnO-Fe_{2}O_{3}-C$ reaction system, and an activation energy of 44 kcal/mol (184 kJ/mol) for ZnO-mill scale-C reaction system.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.101-101
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• 2008

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2015.05a
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• pp.116-117
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• 2015

수소가 없는 고경도 카본막의 수요가 증대됨에 따라, 자장 여과 아크법으로 증착되는 ta-C막을 1um 이상 증착하는 공정 기술에 대한 연구 내용을 발표하고자 한다.

• Proceedings of the KIEE Conference
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• 1999.07d
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• pp.1504-1507
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• 1999

We have grown vertically aligned carbon nanotubes in a large area of Co-Ni codeposited Si substrates by the thermal CVD using $C_2H_2$ gas. Since the discovery of carbon nanotubes, Synthesis of carbon nanotubes for mass production has been achieved by several methods such as laser vaporization arc discharge, and pyrolysis. In particular, growth of vertically aligned nanotubes is of technological importance for applications to FED. Recently, vertically aligned carbon nanotubes have been grown on glass by PECVD Aligned carbon nanotubes can be also grown on mesoporous silica and Fe patterned porous silicon using CVD. Despite such breakthroughs in the growth, the growth mechanism of the alignment are still far from being clearly understood. Furthermore, FED has not been clearly demonstrated yet at a practical level. Here, we demonstrate that carbon nanotubes can be vertically aligned on catalyzed Si substrate when the domain density reaches a certain value. We suggest that steric hindrance between nanotubes at an initial stage of the growth forces nanotubes to align vertically and then nanotubes are further grown by the cap growth mechanism.

• Applied Microscopy
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• v.45 no.4
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• pp.236-241
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• 2015

Carbon-coated Ni, Cu and Sn nanocapsules were investigated by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) and a four-point probe device. All of these nanocapsules were prepared by an arc-discharge method, in which the bulk metals were evaporated under methane ($CH_4$) atmosphere. Three pure metals (Ni, Cu, Sn) were typically diverse in formation of the carbon encapsulated nanoparticles and their different mechanisms were investigated. It was indicated that a thick carbon layers formed on the surface of Ni(C) nanocapsules, whereas a thin shell of carbon with 1~2 layers covered on Cu(C) nanocapsules, and the Sn(C) nanocapsules was, in fact, a longger multi-walled carbon nanotubes partially-filled with metal Sn. As one typical magnetic/dielectric nanocomposite particles, Ni(C) nanocapsules and its counterpart of oxide-coated Ni(O) nanocapsules were compared in the electrically conductive behaviors for further applications as the electromagnetic materials.

• Korean Journal of Materials Research
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• v.26 no.4
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• pp.187-193
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• 2016

Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with $500^{\circ}C/2h$ oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.292-297
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• 2004

Carbon nanotubes (CNT) were synthesized by arc-discharge method. To fabricate CNT sensor, CNT powder was dispersed in ${\alpha}$-Terpinol($C_{10}H_{17}OH$) solution. The CNT tilms were fabricated by screen printing method on the interdigitated Pt/Pd alloy electrode. The microstructure of CNT film was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In order to investigate the gas sensing characteristics of the film, the CNT film was experimented to measure NO response and recovery time. The CNT sensor with a heater was compared to that without a heater. And this sensor shows better reproductibility and faster recovery time than another CNT sensors. We suggest the possibility to utilize a CNT as new sensing materials for environmental monitoring.

• Journal of Korean Vacuum Science & Technology
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• v.6 no.4
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• pp.143-148
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• 2002

Method of plasma-immersion ion deposition of hydrogenated DLC films on relatively thick flat dielectric substrates from plasma of not-self-sustained low-pressure gas arc discharge is suggested. Coating properties have been investigated experimentally, average energy Per a deposited carbon atom depending on discharge current has been calculated. Optimum deposition parameters lot obtaining sufficiently hard and transparent high-adhesive a-C:H films on a 4-mm thick glass substrates have been determined. Possibility to use these coatings for photo-tools protection from abrasion wear at low operating loads is shown in general.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.52 no.3
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• pp.109-115
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• 2003

Diamond-like carbon (DLC) films are deposited at room temperature using a filtered cathodic vacuum arc (FCVA) technique. The influence of negative bias voltage (applied to the substrate from 0 to -250V) on the $sp^3$ hybridized carbon fraction is examined by Raman spectroscopy and x-ray photoelectron spectroscopy (XPS) for C 1s core peak. For the first time, depth profile of C 1s, Si 2p, and O 1s XPS peaks for the deposited DLC film are obtained. DLC film is modeled as a multilayered structure. composing of surface, bulk, and interface. In addition, the x-ray reflectivity (XRR) is proposed as a method for estimating the density, surface roughness, and thickness of each layer constituting the DLC film. The estimated thickness of DLC film is in good agreement with the result obtained from the transmission electron microscope (TEM) measurement.

• Resources Recycling
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• v.7 no.1
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• pp.34-40
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• 1998

This shdy was invcsligated on reduction rate of EAF dust wth solid carbon cantents. The rate equation for reduction ofEAF dust was obtaincd in the tempcrahlrc range cot 910-108O"C, and the ratio of zinc removal and metallization raho of ironoxides to thc reaction time was also analysed. From the XRD analysis for slag residues '||'&'||'er reaction, the cxistcncc DI themixture of Akemmite[Ca2MgSi2O.] and SiO, was identified.ed.