• Title/Summary/Keyword: salt spray

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Experimental Study of Bond Properties Using Coated Bars (도막재료에 따른 철근의 부착성능에 관한 실험적 고찰)

  • 김영진
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.10a
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    • pp.211-216
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    • 2003
  • Coated bars are protecting reinforcing bars from corrosion and enhancing durabilities of reinforced concrete structures are tested to evaluate corrosion protection properties. Tests are performed based on the relevant standards of ACI and ASTM, such as chemical resistance, salt water spray, salt crack test and chloride permeability test with the main variable of the coating thickness. Three type materials are tested by Polyethylene, epoxy and bare bar. Test results show good chemical protection property and chloride permeability. Polyethylene coated bar is good coating material than any other materials.

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A Study on the Economic Evaluation of Thermal Spray Methods for the Corrosion Protection of Steel (금속용사 방식공법의 경제성 평가에 관한 연구)

  • Jung Sung-Ho
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.13-16
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    • 2005
  • Generally, as corrosive protection processing of a steel structure, zinc galvanizing and heavy duty coating paint are applied. However, zinc galvanizing has the difficulty of restriction of a size, or on-site construction. Moreover, heavy duty coating paint has a problem with many administrative and maintenance expenses with short problem of adhesion, corrosion generating of a damage portion, and maintenance management cycle. In this study, a salt water spray test, CASS test, and the electrochemistry examination were carried out for the thermal metal spray method of construction for corrosive protection performance evaluation. Moreover, the corrosive protection life of a thermal metal spray method of construction was quantitatively calculated on the basis of this experiment. in consideration of LCC, the economical efficiency of a general corrosive protection method of construction and a thermal metal corrosive protection method of construction was compared. Consequently, although initial construction expense was estimated 16 to $30\%$ high, as for a thermal metal spray method of construction, it turns out that the administrative and maintenance expenses for 100 years became cheap 9.3 to 13 or more times.

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Soil Salinity and Salt Spray Drift Tolerance of Native Trees on the Coastal Windbreaks in the South-Sea, Korea (한국 남해안방풍림 자생수종의 내염성 및 내조성 수종 선발)

  • Kim, Do-Gyun
    • Korean Journal of Environment and Ecology
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    • v.24 no.1
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    • pp.14-25
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    • 2010
  • This study was carried out to investigate the soil salinity and salt spray drift of the indigenous windbreak trees, and its main purpose was to provide basic data for the selection of salt-tolerant trees in the saline coastal region in the South Sea of Korea. The soil salinity($EC_{1:5}$)was $0.18dSm^{-1}$, which was an average degree of the whole areas of investigation whose salinity degree ranged from $0.05dSm^{-1}$ to $0.58dSm^{-1}$. The level of soil salinity gradually decreased as it moved farther inland, except the belt I. The level of decreasing soil salinity was found to be in the following order: belt II, belt III, belt I, belt IV. The degree of soil salinity was $EC_{1:5}$ $0.22dSm_{1:5}$, $0.22dSm_{1:5}$ $0.19dSm^{-1}$ and $0.13dSm^{-1}$ respectively. The total 110 taxa, which consisted of 45 families, 74 genus, 101 species, and 9 varieties, were found to be tolerant to both soil salinity and salt spray drift. The trees that grow in the highest degree of salinity($EC_{1:5}$ $0.50dSm^{-1}$)were Parthenocissus tricuspidata(Siebold & Zucc.), Planch and Lonicera japonica Thunb. The next group of trees that grow in the high degree of salinity ranging from $EC_{1:5}$ 0.41 to $0.50dSm^{-1}$ was Cudrania tricuspidata(Carr.) Bureau ex Lavall$\acute{e}$e, Rubus parvifolius L., Zanthoxylum schinifolium(Siebold & Zucc.), Hedera rhombea(Miq.) Bean., Robinia pseudoacacia L., Quercus serrata Thunb., Callicarpa dichotoma(Lour.) K. Koch, and so on. The woody species which grew in the entire belts were Pueraria lobata(Willd.) Ohwi and Vitis flexuosa Thunb., and Vitex rotundifolia L. f. which was known to be highly tolerant to salt spray drift was found only in belt I. The woody species with high important value(IV) were Zelkova serrata(Thunb.) Makino., Celtis sinensis Pers., Koelreuteria paniculata Laxmann, Mallotusjaponicus(Thunb.) Muell. Arg., Trachelospermum asiaticum(Siebold & Zucc.) NAKAI, and Pueraria lobata(Willd.) Ohwi. These species were classified as native windbreak trees that are comparatively more tolerant to salt spray drift than other kinds.

Manufacturing Process and Component Analysis of Seawater Salt Using Seaweeds (해조류를 이용한 해수소금 제조기법 및 성분분석)

  • Lee, Seung-Won;Kim, Hyeon-Ju;Moon, Deok-Soo;Jung, Dong-Ho;Choi, Hark-Sun
    • Journal of Ocean Engineering and Technology
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    • v.21 no.4
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    • pp.61-65
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    • 2007
  • In this research, we have developed a manufacturing process for seawater salt by horizontal spray drying technique using the deep ocean water and seaweed(sea tangle). Deep ocean water, strong acidic electrolyzed water and strong alkaline electrolyzed water were used as extraction solvent of seaweed. Sodium content in seaweed extract solution by strong alkaline electrolyzed water was 1.63(mg/g), which was 3.5 times lower than of seaweed extract by strong acidic electrolyzed water. Major mineral content(Na, K, Ca) in seawater salt by deep ocean water were higher than strong acidic electrolyzed water and strong alkaline electrolyzed water. On the contrary, Mg contents in seawater salt by deep ocean water were lower than strong acidic electrolyzed water and strong alkaline electrolyzed water. Based on the results of seawater salt production using seaweed, it is possible to make law-salt efficiently.

Hot Corrosion Behavior of Plasma-Sprayed Partially Stabilized Zirconia Coatings in a Lithium Molten Salt (리튬용융염에서 플라즈마 용사된 부분안정화 지르코니아 코팅층의 고온부식 거동)

  • Cho, Soo-Haeng;Hong, Sun-Seok;Kang, Dae-Seong;Park, Byung-Heong;Hur, Jin-Mok;Lee, Han-Soo
    • Korean Journal of Metals and Materials
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    • v.46 no.10
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    • pp.646-651
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    • 2008
  • The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which results in a chemically aggressive environment that is too corrosive for typical structural materials. It is essential to choose the optimum material for the process equipment handling molten salt. IN713LC is one of the candidate materials proposed for application in electrolytic reduction process. In this study, yttria-stabilized zirconia (YSZ) top coat was applied to a surface of IN713LC with an aluminized metallic bond coat by an optimized plasma spray process, and were investigated the corrosion behavior at $675^{\circ}C$ for 216 hours in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere. The as-coated and tested specimens were examined by OM, SEM/EDS and XRD, respectively. The bare superalloy reveals obvious weight loss, and the corrosion layer formed on the surface of the bare superalloy was spalled due to the rapid scale growth and thermal stress. The top coatings showed a much better hot-corrosion resistance in the presence of $LiCl-Li_2O$ molten salt when compared to those of the uncoated superalloy and the aluminized bond coatings. These coatings have been found to be beneficial for increasing to the hot-corrosion resistance of the structural materials for handling high temperature lithium molten salts.

Microstructure and Properties of Plasma Spray Coatings Prepared from Ti-Zr-Ni Quasicrystalline Powders

  • Seok, H.K.;Kim, Y.C.;Prima, F.;Fleury, E.
    • Proceedings of the Korean Powder Metallurgy Institute Conference
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    • 2006.09a
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    • pp.53-54
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    • 2006
  • Ti-Zr-Ni coatings deposited by low vacuum plasma spray technique consisted of nanometer-sized $W-Ti_{50}Zr_{35}Ni_{15}$ 1/1 cubic approximant and TiZrNi Laves phases as well as a low volume fraction of $ZrO_2$ phase. The shift of composition during deposition of the quasicrystalline powders and the presence of $ZrO_2$ phases are believed to be responsible for the reduced corrosion performances evaluated by means of electrochemical tests in a Hanks' Balance Salt Solution at $37^{\circ}C$.

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The Performance and Application of Repair System for the Exterior Wall According to the Durability Improvement in the RC Structure (Part1. Theoretical approach to the repair technic) (내구성 향상을 고려한 R.C조 외벽 보수 시스템의 성능과 그 활용 (제1보 : 열화 요인별 외벽 보수기술))

  • Kwon, Young-Jin;Kim, Chul-Ho;Kwak, Young-Jun;Park, Deuk-Kon;Choi, Long
    • Proceedings of the Korea Concrete Institute Conference
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    • 1995.10a
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    • pp.134-138
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    • 1995
  • The reinforced concrcte structure were once belicved to have permanent durability. However, it is now spoiled by durability failure caused by the corrosion of embeded steel reingorcement carbonation. alkali-aggregate reaction and salt attack Recently. salt damage has been also spreading. Salt damage is found in concrete structures built using seasands or certain admixtures containing calcium chlorides and in coastal structures frequently caught in seawater spray or blown by seawind It is the aim of this study to investigate the performance and application of new repair system for the exterior wall according to the durability improvement in the RC structures.

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Study on the Naturalized Plant Management Applying the Growth and Physiological Characteristics Responses in Coastal Sand Dune (해안사구에서 생장 및 생리적 특성을 적용한 귀화식물 관리방안)

  • Kim, Nang-Hee;Lee, Seon-Mi;Myeong, Hyeon-Ho
    • Korean Journal of Ecology and Environment
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    • v.48 no.1
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    • pp.32-37
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    • 2015
  • Naturalized plants are invaded through various routes and distributed throughout the nation. They are also invaded in the sand dune ecosystem and poses a threat ecological niche of indigenous sand dune plants. We studied the effects of salt stress on the plant growth to suggest the management plans of naturalized plants in the sand dune ecosystem. As a result of germination experiment according to the salt gradient, germination rate decreased as the higher concentration and tolerance range was up to 160 mM. As a result of seedling experiment according to salt gradient, mortality rate was up to 90% from 0 mM to 200 mM and 100% over 300 mM. The day of first death with different concentration was 18.5 days in 100 mM and 6 days in 800 mM since the experiment has started. In addition, the day of last death with different concentration was 29.5 days in 100 mM and 6 days in 800 mM. Therefore, two stages of management plans would be effective. The first one is to suppress the germination by salt spray over 170 mM before germination. The other one is to wither seedlings in a short period by salt spray over 600 mM.

Durability of Carbon/Epoxy Composites for Train Carbody under Salt Water Environment (염수환경에 노출된 철도차량용 탄소섬유/에폭시 복합재의 내구성 평가)

  • Yoon, Sung-Ho;Hwang, Young-Eun;Kim, Jung-Seok;Yoon, Hyuk-Jin;Kessler, Michael R.
    • Journal of the Korean Society for Railway
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    • v.11 no.4
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    • pp.357-363
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    • 2008
  • This study investigates the durability of carbon/epoxy composites for use on train car bodies under a salt water spray environment. Salt water solution with 5% NaCl, similar to natural salt water, was used for the salt water environmental tests. The specimens were obtained from a composite panel consisting of an epoxy matrix reinforced with T700 carbon fabric. The specimens were exposed to the salt water environment for up to 12 months. Mechanical tests were performed to obtain tensile properties, flexural properties, and shear properties. Dynamic mechanical analysis was used to measure such thermal properties as storage modulus, loss modulus, and tan $\delta$. Also FT/IR tests were conducted to investigate changes in chemical structure with exposure. The results revealed that fiber-dominated mechanical properties were not affected much by exposure time, but matrix-dominated mechanical properties decreased with increasing exposure time. Storage modulus was not very sensitive to exposure time, but glass transition temperature was affected, slightly decreasing with increasing exposure time. Although the peak intensity of FT/IR curves was affected slightly by exposure time, the peak shape and peak location of FT/IR curves were not noticeably changed. Carbon/epoxy composites used for this study were relatively stable to the salt water environment.

Mechanical Properties and Corrosion Resistance of Plasma Electrolytic Oxidation Coatings on AZ31 Magnesium Alloy

  • Park, Jae Seon;Jung, Hwa Chul;Shin, Kwang Seon
    • Corrosion Science and Technology
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    • v.5 no.2
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    • pp.77-83
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    • 2006
  • The plasma electrolytic oxidation (PEO) process is a relatively new surface treatment technique that produces a chemically stable and environment-friendly electrolytic coating that can be applied to all types of magnesium alloys. In this study, the characteristics of oxide film were examined after coating the extruded AZ31 alloy through the PEO process. Hard ceramic coatings were obtained on the AZ31 alloy by changing the coating time from 10min to 60min. The morphologies of the surface and the cross-section of the PEO coatings were examined by scanning electron microscopy and optical microscopy, and the thickness of the coating was measured. The X-ray diffraction pattern of the coating shows that the coated layer consists mainly of the MgO and $Mg_2SiO_4$ phases after the oxidation reaction. The hardness of the coated AZ31 alloy increased with increasing coating time. In addition, the corrosion rates of the coated and uncoated AZ31 alloys were examined by salt spray tests according to ASTM B 117 and the results show that the corrosion resistance of the coated AZ31 alloy was superior to that of the un-coated AZ31 alloy.