• Journal of the Korean Society of Marine Environment & Safety
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• v.12 no.4 s.27
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• pp.253-259
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• 2006

This paper investigated on anti-corrosion characteristic in chemical decontamination at extremely severe condition{process model-2) of stainless steels used with reactor coolant pump. The electrochemical properties of stainless steel{STS) 304 with the lapse qf cycle is better than those of STS 415 and STS 431. The STS 304 in process model-1 and process model-2 present the lowest weightloss ratio. The experiment results for STS 304, STS 415, and STS 431 in process model-2 solution, it was ascertained that weightloss ratio of process model-2 solution for process model-1 solution show 2..908, 2.572, and 2.370 times, respectively. The reason suggests that process model-2 is higher concentration of chemical and temperature compare to process model-1.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.61-68
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• 2019

As the pollution of water resources deteriorates due to industrialization and urbanization, it is difficult to supply clean water through a water treatment method using chlorine. Therefore, the introduction of advanced water treatment facilities using ozone is on the increase. However, epoxy which is used as waterproofing and anticorrosives and stainless steel used in conventional waterproofing and anti-corrosive methods have deteriorated because of the strong oxidizing power of ozone, causing problems such as leaking. Moreover, it even causes the durability degradation of a concrete. Therefore, in this study, metal spraying system was used as the means of constructing a metal panel with excellent ozone resistance and chemical resistance which is an easier method than an existing construction method. Ozone resistance was evaluated in accordance with the type of metal sprayed coatings to develop a finishing method which can prevent the concrete structure of water treatment facilities from deterioration. Furthermore, electrochemical stability in actual sewage treatment plant environment was evaluated. Experimental results showed that Ti has superior ozone resistance after spraying and the electrochemical stability in the sewage treatment plant environment showed that Ti has the highest polarization resistance of $403.83k{\cdot}{\Omega}{\cdot}cm^2$, which ensures high levels of durability.

• Journal of Technologic Dentistry
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• v.33 no.2
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• pp.121-128
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• 2011

Purpose: The purpose of this study is to investigate the level of each metal in non-precious metal alloys dental casting, still used even banned for use and trade by the law, for oral health. Methods: Two kinds of metal alloys were analyzed. One was Ticonium 100 for removable prosthesis and the other was Rexillium V for dental porcelain. Two samples of each metal alloy were made in 0.5g, 1.0g, and 1.5g. Total number of samples were 12. Two kinds of lactic acid Solution, pH7 and pH4.6, were injected into each samples. After injection, each samples had been for 21days ${\pm}$ 1 hour in the water tank of which temperature was $37^{\circ}C$. The level of metal was measured in each sample by inductively couplled plasma-atomic emission spectrometer. Results: In both metal alloys, metals, chrome, nickel, beryllium, and molybdenum, were founded. In Ticonium 1000, the highest level of nickel was 2.531ppm in 1.5g pH4.6 sample while the highest level of nickel was 4.062ppm in 1.5g pH4.6 sample of Rexillium V. In chemical composition of these methal alloys, chrome(14~17%) was much more than beryllium(1.95~1.99%) and molybdenum(5.0~9.0%) but berllium and molybdenum were founded more than chrome in samples. Therefore, chrome showed better anti-corrosion than other metal alloys. In both metal alloys, more metals were founded in higher pH level and more mass. Levels of chrome was significantly different in samples of both metal alloys in each pH level(p<0.05). Levels of nickels was significantly different in samples of both metal alloys in each pH level(p<0.05). Conclusion: For oral health, further studies are needed in nickel-chrome metal alloy and cobalt metal alloy of non-beryllium in addittion to beryllium metal alloy and also long-term studies needed in various period and other non-percious metal alloys for dental casting.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.42-50
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• 2016

Overlay welding affects the chemical components and weld hardness by dilution of the lamination layer thickness, which determines the surface properties. This study experimentally investigates different numbers of layers for overlay welding monel materials, which are anti-corrosion materials. The Fe content, weldability of the base metal and monel materials, hardness, and surface flatness were examined. Each evaluation was carried out after overlay welding with three layers on the base material and pipe base material of the plate. The Fe content was evaluated by analyzing the constituents of each layer. The Fe content was satisfactory in the three layers. The weldability of the laminate specimens was evaluated by a bending test. The hardness and bead flatness of the laminate specimens were evaluated by micro Vickers and 3D measurements. The hardness was highest in the heat-affected zone with one layer, and it decreased with increasing lamination. In the case of bead flatness, there is a sharp difference in the deviation with increasing numbers of laminations, which should be considered carefully.