• 한국세라믹학회지
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• 제45권3호
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• pp.161-166
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• 2008

The multi-films of a metallic film and a transparent conducting oxide (TCO, indium-tin oxide, ITO) film were formed on the stainless steel 316 and 304 plates by a sputtering method and an E-beam method and then the external metallic region of the stainless steel bipolar plates was converted into the metal nitride films through an annealing process. The multi-film formed on the stainless steel bipolar plates showed the XRD patterns of the typical indium-tin oxide, the metallic phase and the metal substrate and the external nitride film. The XRD pattern of the thin film on the bipolar plates modified showed two metal nitride phases of CrN and $Cr_2N$ compound. Surface microstructural morphology of the multi-film deposited bipolar plates was observed by AFM and FE-SEM. The metal nitride film formed on the stainless steel bipolar plates represented a microstructural morphology of fine columnar grains with 10 nm diameter and 60nm length in FE-SEM images. The electrical resistivity of the stainless steel bipolar plates modified was evaluated.

• 한국의류산업학회지
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• 제8권6호
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• pp.702-708
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• 2006

The purpose of this study was to investigate the dyeing-property and antibacterial activity on nylon fabric dyed with cochineal at variable dyeing conditions. Al, Cr, Fe, Cu and Sn were used as mordants and adsorption was compared with different mordanting methods. The maximum UV-visible absorption band of cochineal extract was 495 nm. The dyeability on nylon fabric was good because of having a amine group. The optimum dyeing conditions of nylon fabrics are dyeing concentration 1.5%(o.w.s), dyeing temperature $60^{\circ}C$, pH 3 and dyeing time 30 minutes. The pre-mordanting method is preferred for Al and Cr, and the post-mordanting one is preferred for Cu, Sn and Fe to achieve better dyeing. The optimum mordanting conditions of wool fabrics dyed with cochineal are mordanting concentration of 0.5%(o.w.s), mordanting temperature $60^{\circ}C$, and dyeing time 30 minutes. Nylon fabrics dyed with cochineal show a little antibacterial activity, but it was increased by Sn mordanting. MIC test results in antibacterial activities revealed that the antibacterial activity of Cu was the highest among mordants, but Sn mordant was the most effective in antibacterial activities after mordanting treatment of nylon fabric. The fastness properties of dyed nylon fabric showd a little worse or a similar level and there was no significant difference between a mordanted and non-mordanted fabric.

• 한국주조공학회지
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• 제16권2호
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• pp.124-131
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• 1996

High temperature properties such as hot hardness and thermal fatigue resistance of high speed steel roll of hot finishing mill have been investigated. Two kinds of roll having compositions, Fe-1.75%C-5.9%Cr-1.74%Mo-4.94%V-2.03%W(A specimen) and Fe-2.27%C-8.86%Cr-2.91%Mo-3.92%V-1.86%W(B specimen)were prepared for investigating the microstructure and crack propagation mode. A specimen has greater amounts of $M_7C_3$ type carbides and less amounts of MC type carbides in comparison with B specimen. Hot hardness showed sudden decrease over $400^{\circ}C$, resulting in the hardness decrease of 50% at the temperature of $600^{\circ}C$, and showed little variation with time at $500^{\circ}C$ and $800^{\circ}C$. Thermal crack was developed at $550^{\circ}C$ in A specimen and $600^{\circ}C$ in B specimen.

• Journal of Welding and Joining
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• 제11권1호
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• pp.62-72
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• 1993

Recently there is an increased interest in joining of ceramics to metals and brazing now an accepted method of joining for a wide variety of ceramic to metal combination. The present research work is aimed at establishing the basis of the metal-ceramic joining of $Al_{2}$O$_{3}$ to STS 304 with using Cu-7.5wt% Zr insert metals. Also the microstructures of the brazed joints were observed by using optical microscope and SEM and the reaction products were analyzed by using EDX, WDX and XRD. As a result, the following findings were obtained. The reaction layers of the brazed joints of $Al_{2}$O$_{3}$ to STS 304 are composed of four layers at the bonded interlayer. Double reaction layers are formed at the interface of $Al_{2}$O$_{3}$ insert metal. Layer I was composed of ZrO$_{2}$ particles, Fe-Cr-Ni compounds in Cu matrix, while layer II ZrO$_{2}$ band phase containing Fe-Cr-Ni compounds.

• Journal of the korean society of oceanography
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• 제32권3호
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• pp.120-127
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• 1997

Depositional environment off the Shihwa Dam has been studied to investigate the change of sedimentation process and the pollution. In order to understand how the sediments are distributed, polluted and modified, depositional factors have been analyzed and compared with the previous data. Study area, located off the Shihwa Dam, was surveyed to collect 25 bottom samples and 2 cores in 1996 and echo-sounding in 1997. These sediments were analyzed for the study of the global characteristics of sediment such as grain size and organic matter. Among these samples, the selected twenty surface sediments were analyzed for the comparison with their contents of metallic elements (Al, Mn, Fe, V, Cr, Co, Ni, Cu, Zn, Cd, Pb, As). According to field and lab analysis of sediments, three sedimentological zones have been generally identified around study area; near the dam (sandy Silt), near the dike (Sand) and offshore (silty Sand) zones. Textural parameters show that the content of silt and clay is dominant near the dam excepting the dike zone of LNG Storage Base and offshore (Palmido). The total concentration of Mn, Ni, Fe, Zn and Cd in bulk sediments was increased after the construction of the dam, while the content of Mn and Cr were higher near tidal channel than in the offshore area. Meanwhile, the annual increasing pattern of some heavy metal has appeared in this area. Based on this primary study, modification of the depositional environment may be caused by the construction of the dam and LNG Storage Base. Additionally, environmental evaluation on organic/inorganic factors has been suggested for interpreting environmental changes caused by coastal development in the nearshore such as the Shihwa coastal area.

• 열처리공학회지
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• 제1권1호
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• pp.1-7
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• 1988

In this study the improvement of mechanical properties of ion-nitrided SACM-1 steel was investigated by analysing microstructural developments and hardness increase in the nitrided surface layer. Specimens were quenched at $570^{\circ}C$, which is lower than the eutectoid temperature ($590^{\circ}C$) of Fe-N binary system after nitrided at temperature of $460-570^{\circ}C$ for 2-8 hours under constant pressure of 8 torr. The depths of diffusion and compound layers were appeared to proportional to the root mean square time of nitriding. And the hardness showed the maximun value Hv = 1200 for the specimen nitrided at $530^{\circ}C$. Hardness distribution of the. ion-nitrided steels were increased by diffusion treatment below the eutectoid temperature of the Fe-N binary system. A prolonged heat treatment below the eutectoid temperature was attributed to the increase in the depth of diffusion layer at the expense of the decrease in surface hardness of the ion nitreded steel.

• 한국염색가공학회지
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• 제25권4호
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• pp.327-336
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• 2013

The purpose of this study was to evaluate the color image of the natural-dyed silk fabrics. The dye was extracted from pine needle by boiling pine needle with ethanol at $78^{\circ}C$ for 3hours and distilled water at $100^{\circ}C$ for 2hours. The 100% silk fabric was dyed of extract in pH 5 at $90-100^{\circ}C$ for 1 hr. As mordants used were compounds of Al, Sn, Fe, and Cr, color image of pine-needle dyed silk fabrics was classified into 5 factors (pure, gentle, sophisticate, comfortable, pastorale) and the factor pure is most important one of those. Most cheerful image in pure factor was from the fabrics dyed with ethanol extract and then, none and Cr mordanting. Dignified image was from the fabrics dyed with ethanol extract and then, Cu or Fe mordanting. In production, products dyed with ethanol extracts was preferred to those dyed with distilled water extracts. Color image and preference of the silk fabrics dyed with pine needles extracted was affected by extraction solvents and mordants.

• 한국표면공학회지
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• 제51권3호
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• pp.172-178
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• 2018

In this paper, effects of potassium permanganate, pottasium dichromate, sodium molybdate on lean duplex stainless steel were studied by GDOES, OCP, potentiodynamic curves. The stainless steels were chemically passivated in each nitric acid solutions containing 4wt.% oxidants for 1 hour. As a result, when potassium dichromate or sodium molybdate was added, content of Fe was decreased and content of Cr was increased. Consequently, corrosion resistance of passive film was increased. But in case of potassium permanganate was added, contrastively, content of Fe was increased and content of Cr was decreased. So corrosion resistance was decreased. Adding sodium molybdate in nitric acid for chemical surface treatment process was the most effective among oxidants and also it showed the most stable anti-corrosion in SST.

• 한국의류학회지
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• 제38권5호
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• pp.665-674
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• 2014

An analysis of the components of clay mineral before and after coloration (XRF) showed that the elements involved in coloration are Fe, Cr, and Ni. Fe accounts for 65% of coloring components on dyed fabric; in addition, Cr and Ni also affect coloring. The optimal coloration condition was to repeat the process of immersing the cotton fabric in $80^{\circ}C$ slurry of 8g of clay mineral to 1g cotton for 60 minutes, dry it for 24 hours and rinse three times. Especially, as the repetition of coloration increased, the $(K/S)_{440}$ value of sample A increased from 1.0 to 2.5, and sample B increased from 1.0 to 1.6. The effect of the repeated process on coloration was significant; consequently, the rinsing and drying process were important to decrease the coloration level. It also showed excellent results in regard to color fastness to washing, light, rubbing, perspiration, and antibiotic effect.

• Applied Microscopy
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• 제46권1호
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• pp.45-50
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• 2016

Iron containing a high amount of chromium is known to be inferior to ductility due to ${\sigma}$ phase formation so that it is generally difficult to apply the plastic deformation process although the alloy possesses a superior characteristics of an excellent corrosion resistance. In this study, Fe-50mass%Cr alloy was melted using high purity powder and the deformation behavior has been investigated by cold rolling and tensile test. The tensile test yielded that the alloy revealed a serration at an early stage of tensile deformation and then the serrated flow vanished to change to a normal work hardening flow at the later stage. The former was governed by twin formation process, the latter by dislocation multiplication one, bringing about a high ductility of 20% or over. The reduction ratio in cold rolling was attained as high as 90%, thus the high corrosion-resistant alloy is able to possess a high ductility.