• Journal of the Korean Data and Information Science Society
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• v.28 no.4
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• pp.811-818
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• 2017

Environmental tests are used to verify a equipment that can withstand the rigors of harsh environments. In case of military products for export, the tests have to be based on the climatic data of the world. However, if the climatic data of the world is used for domestic military products, it may cause an increase in manufacture price. There is currently no climatic data that can be used as criteria for the tests in the Korean peninsula and coastal seas. Therefore, this paper suggests a water temperature and a salinity guidelines of salt fog tests for military products used in the area. As a result, we present water temperature and salinity information that is extreme and FOO of the Korean coastal seas.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.489-489
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• 2013

AF 코팅은 유리나 플라스틱과 같은 기재 표면을 특수 처리하여 지문과 같은 오염물질의 부착방지와 오염물질이 부착되더라도 쉽게 제거 가능하도록 하는 기술이다. 전자, 자동차, 건축, 섬유, 철강분야 등에 활용 가능한 중요기술로 박막의 발수 발유 기능을 부여하는 표면처리 기술이고, 코팅방법에는 진공증착, 스핀코팅, 딥코팅, 플로우 코팅, 스프레이 코팅 등이 있으며, 경화 방법이나 접촉각 등의 특성이 반영된다. 터치패널 등의 지문부착방지 기술은 불소계와 비불소계 재료로 구분할 수 있지만 지문을 쉽게 지울 수 있고, 오염 방지 기능과 내구성이 있으며, 우수한 광학특성을 유지하는 것이 과제라 할 수 있다. 그리고 항균성을 부여하는 기술도 개발되고 있다. 이런 터치패널의 강화유리에 AF 코팅한 제품은 핸드폰 글래스에 처음 적용하면서부터 실생활에 도입이 시작되고 있다. 이러한 AF 코팅을 스퍼터링 법을 이용하여 증착 시켰다. 기존에는 E-beam을 이용한 증착 방식이 주를 이루었지만, 스퍼터링 법을 이용함으로써 박막의 균일화 및 대량생산이 가능해졌다. 따라서 이 연구에서는 기존의 E-beam 방식과 sputtering 공정 중 ion source에 의한 전처리의 유무에 따른 박막의 특성을 비교하였다. 내부식성, 내마모성 시험을 거친 후, 접촉각을 측정하여 알아보았으며, 박막의 건전성 및 균일성은 FE-SEM을 이용하여 관찰하였다. 실험용 장비가 아닌 실제 생산장비인 직경 1,400 파이의 장비를 이용하여 증착하였으며 염수분무 및 내마모 시험 후, 기존 접촉각의 ${\pm}5^{\circ}$ 내외임을 확인 할 수 있었고, 박막의 건전성 또한 뛰어남을 알 수 있었다.

• Journal of Ocean Engineering and Technology
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• v.25 no.1
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• pp.32-38
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• 2011

Galvanized steel has gone through a chemical process to keep it from corroding. The steel gets coated in layers of zinc because rust will not attack this protective metal. For countless outdoor, marine, or industrial applications, galvanized steel is an essential fabrication component. The reduction of the corrosion rate of zinc is an important topic. In the past, a very popular way to reduce the corrosion rate of zinc was to use chemical conversion layers based on $Cr^{+6}$. However, a significant problem that has arisen is that the use of chromium salts is now restricted because of environmental protection legislation. Therefore, it is very important to develop new zinc surface treatments that are environmentally friendly to improve the corrosion resistance of zinc and adhesion with a final organic protective layer. In this study, a Urethane solution (only Urethane 20 wt.%; S-700) and an organic/inorganic solution with Si (Si polysilicate 10 wt.% + Urethane 10 wt.%; LRO-317) are used. Based on the salt spray test of 72 h, S-700 and LRO-317 had a superior effect for the corrosion resistance on EGI and HDGI, respectively.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.67-74
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• 2010

Chromate conversion coating is a coating technique used to passivate aluminum, zinc, cadmium, copper, silver, magnesium, tin, and their alloys to slow corrosion. The process uses various toxic chromium compounds, which may include hexavalent chromium. The industry is developing less toxic alternatives in order to comply with substance restriction legislation, such as RoHS. One alternative is to develop a Cr-free coating solution. In this study, eco-friendly, Cr-free solutions (urethane solution S-700, organic/inorganic solution with Si LRO-317) were used. Test specimens were dried in a drying oven at $190^{\circ}C$ for 3, 5, 7, and 9 minutes. Corrosion resistance was evaluated using a salt spray test for 72 hours. The results show that the optimum corrosion resistance was achieved at $190^{\circ}C$ for five minutes for EGI and three or five minutes for HDGI, respectively. The adhesive properties of the two types of coating solutions were superior regardless of drying time.

• Journal of Ocean Engineering and Technology
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• v.24 no.5
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• pp.60-66
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• 2010

Zinc has a number of characteristics that make it well suited for use as a coating to protecting iron and steel products from corrosion. Its excellent corrosion resistance in most environments accounts for its successful use as a protective coating on a variety of products and in many exposure conditions. The excellent field performance of zinc coatings results from their ability to form dense, adherent films that corrode at a rate that ranges from 1% to 10% of the corrosion rate of ferrous materials, depending on the environment. Recently, EU RoHS and EU ELV prohibited the use of materials that adversely affect the environment, such as Pb, Hg, Cd, and $Cr^{+6}$. In this study, environmentally-friendly, Cr-free solutions (epoxy solution, acrylic solution, and urethane solution S-700) and organic/inorganic solution with Si; LRO-317) were used to evaluate the corrosion resistance of zinc-coated steel subjected to a saltwater spray for 72 hours. The coating of urethane solution (S-700) was best among the three kinds of solution with heat treatment during five minutes at $190^{\circ}F$. Test specimens with S-700 and LRO-317 coating were heat treated in a drying oven at 170, 180, 190, 200, and $210^{\circ}C$ for five minutes. The results show that the optimum corrosion resistance was $190^{\circ}C$ in EGI and $170^{\circ}C$ in HDGI, respectively.

• Journal of Ocean Engineering and Technology
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• v.25 no.6
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• pp.56-59
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• 2011

The demand for cold rolled steel (CR) for structural members is gradually increasing. If no surface treatment (coating for corrosion resistance) for CR is conducted, its use is very limited because CR is vulnerable to corrosion. Therefore, we need to develop a coating solution to provide high corrosion resistance for CR. In this study, an organic/inorganic coating solution with Si and Ti (Si polysilicate 7 wt.% + Urethane 13 wt.% + Ti amorphous 0.5 wt.%; LR-0727(1)) was used to evaluate the corrosion resistance of CR under a salt spray test. The specimens with the LR-0727(1) coating were heat treated in a drying oven at $120{\sim}210^{\circ}C$for 5 min. The corrosion resistance was investigated using a salt spray test of 7 h. In addition, an adhesive test was conducted. Rust showed under a heat treatment of $150^{\circ}C$, but no vestiges were found over $160^{\circ}C$. The specimens with heat treatment at $160^{\circ}C$ or more did not experience delamination. From these results, it is considered that the temperature limit for optimum heat treatment is $160^{\circ}C$ considering energy efficiency.

• Polymer(Korea)
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• v.34 no.5
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• pp.405-409
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• 2010

New sol-gel precursors having the ability to protect iron against corrosion were synthesized and used to prepare organic-inorganic hybrid coatings based on epoxy. Bisphenol A epoxy was modified with 3-isocyanatopropyltriethoxysilane to improve the compatibility, and water and HCl were used as catalysts for sol-gel process. Various coating formulations were prepared depending on the type of sol-gel precursors and the amount of each ingredient, and cast on iron substrates by dip-coating and thermally cured. Corrosion protection properties of coated iron were studied by a salt spray test and electrochemical impedance spectroscopy under 0.1 M NaCl electrolyte. Hybrid coatings containing anticorrosive functional group exhibited excellent corrosion protection on iron, compared to that of typical hybrid coatings. From electrochemical impedance spectroscopy, the hybrid coatings containing anticorrosive functional group could maintaine the initial impedance after 500 h, while the impedance of hybrid coatings without them started to decrease after 24 h.

• Journal of Power System Engineering
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• v.13 no.3
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• pp.33-39
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• 2009

The aim of this study is to analyze the welds characteristics of the 205 stainless steel pipe for application of street pole material. The welds corrosion behavior of STS 205 pipe in 0.1 N sulphuric acid solution and 5% NaCl solution at room temperature was studied using both salt spray test and potentiodynamic polarization experiment. The morphology and components of corrosion products on surface of STS 205 pipe welds were investigated using SEM/EDX. The tensile strength and yield strength values of STS 205 plate were 715 MPa and 369 MPa respectively. The microvickers hardness values of STS 205 pipe welds were slightly increased than that of STS 304 pipe welds. Corrosion current density($I_{corr.}$) and critical current density($I_{crit.}$) values of STS 205 pipe welds in 3.5% NaCl solution were $1.89{\times}10^{-6}$ $A/cm^2$ and $15.8{\times}10 ^{-6}$ $A/cm^2$. The corrosion resistance of SIS 205 pipe welds was similar to its STS 304 pipe welds. The STS 205 and 304 pipe welds passive films were chromium oxide. Especially, the STS 205 pipe welds showed good corrosion resistance in 0.1 N sulphuric acid. This is attributed to the forming of protective chromium oxide on the surface of STS 205 pipe welds.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.182-182
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• 2013

빗각 증착은 입사 증기가 기판에 수직하게 입사하는 일반적인 공정과는 다르게 증기가 기판의 수직선과 $0^{\circ}$ 이상의 각을 갖는 증착 방법을 의미한다. 빗각 증착으로 코팅층의 구조를 제어하기 위해서는 기판에 입사되는 코팅 물질의 증기가 일정한 각도를 유지해야한다. 공정 압력이 높아서 증기의 자유행로가 짧아지면 기판에 도달하는 코팅 물질이 일정한 각도를 유지하지 못하기 때문에 코팅층의 구조제어가 어렵고 일반적인 코팅 공정과 유사한 구조의 코팅층을 얻게 된다. 빗각 증착을 공정 압력이 비교적 낮은 전자빔 증착이나 열 기상증착 등의 코팅 공정에서 실시하는 이유이다. 본 연구는 공정 압력이 ${\sim}10^{-3}$ torr로 비교적 높은 스퍼터링 공정에서 빗각 증착을 실시하여 코팅층의 구조제어가 가능한지를 확인하였다. 실험에 사용된 물질은 알루미늄이었으며 빗각은 $0{\sim}90^{\circ}$를 사용하였다. 실험 결과 빗각의 크기가 $60^{\circ}$ 이하에서는 알루미늄 박막의 구조 변화를 관찰하지 못했으며 $45^{\circ}$와 같은 특정한 빗각에서 밀도가 높은 코팅층을 확인할 수 있었다. 이러한 높은 밀도를 갖는 알루미늄 박막은 강판의 부식을 방지하기 위한 보호막으로 적용이 가능할 것으로 판단되며 염수분무시험 결과 200시간 이상의 높은 적청 발생 시간을 보였다. $60^{\circ}$ 이상의 빗각으로 코팅된 알루미늄 박막에서 독립적으로 형성된 주상정을 관찰할 수 있었다. 빗각의 크기가 $90^{\circ}$로 스퍼터링 타겟과 기판을 수직하게 위치시켜도 알루미늄 박막이 코팅되는 것을 확인할 수 있었으며 일정한 각도를 가지는 주상정을 관찰할 수 있었다. 이러한 주상정의 알루미늄은 비교적 큰 표면적을 가지고 있기 때문에 가스 센서 등 다양한 응용분야에 적용이 가능할 것으로 판단된다. 앞서 설명한 실험결과와 같이 스퍼터링과 같이 공정 압력이 비교적 높은 공정에서도 빗각 증착을 이용한 코팅층의 구조 제어가 가능하다는 것을 확인할 수 있었다.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.836-839
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• 2005

A limit switch box is used for a indicator of a valve actuator. This device indicates an opening and closing of a valve or throttle in a valve actuator. In a ship, equipments are required safety and robustness because of a rough environment and a specific condition during a voyage. However, the limit switch box is used in an indoor environment generally. In order to evaluate the endurance of the limit switch box used in an indoor environment, the endurance tests against salt water have been conducted. Experiment results showed that the limit switch box was corroded severely. Thus, this study developed a new limit switch box which can be used at an outdoor environment. The housing of the developed limit switch box was made by an stainless steel to prevent corrosion.