• 공업화학
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• 제27권3호
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• pp.265-269
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• 2016

수소가 청정 에너지 원으로서의 중요성이 증가하면서 수소의 생산원인 암모니아 기체가 큰 주목을 받고 있다. 그러나 암모니아가 금속을 잘 부식시키고 유독성을 가지고 있기 때문에 암모니아의 저장과 운반을 가능하게 하는 흡착제의 연구가 다각도로 진행되고 있다. 이 중 공유결합 유기구조 물질(covalent organic framework)의 하나인 COF-10은 붕소를 포함한 큰 기공을 가진 물질이다. 암모니아 흡착과정에서 COF-10의 구조 안에 있는 붕소는 루이스 산으로 작용하여 암모니아와 강한 결합을 한다. 본 논문에서는 이러한 COF-10을 합성하여 BET, XRD, FT-IR을 통해 구조를 확인한다. 또한 TPD와 등온 흡착 실험을 통해 실제 암모니아의 흡착능력에 대한 분석을 진행하였다. COF-10는 9.79 mmol/g으로 우수한 암모니아 흡착 능력을 보였으며 암모니아 흡착제로서 활용 가능할 것으로 사료된다.

• Corrosion Science and Technology
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• 제10권2호
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• pp.52-59
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• 2011

Corrosion of metallic materials occurs by the reaction with corrosive environment such as atmosphere, marine, soil, urban, high temperature etc. In general, reduction of thickness and cracking and degradation are resulted from corrosion. Corrosion in all industrial facilities and infrastructure causes large economic losses as well as a large number of accidents. Economic loss by corrosion has been reported to be nearly 1-6% of GNP or GDP. In order to reduce corrosion damage of industrial facilities, corrosion map as well as a systematic investigation of the loss of corrosion in each industrial sector is needed. The Corrosion Science Society of Korea in collaboration with 15 universities and institutes has started to survey on the cost of corrosion and corrosion map of Korea since 2005. This work presents the results of the survey on cost of corrosion by Uhlig, Hoar, and input-output methods, and the evaluation of atmospheric corrosion rate of carbon steel, weathering steel, galvanized steel, copper, and aluminum in Korea. The total corrosion cost was estimated in terms of the percentage of the GDP of industry sectors and the total GDP of Korea. According to the result of Input/output method, corrosion cost of Korea was calculated as 2.9% to GDP (2005). Time of wetness was shown to be categories 3 to 4 in all exposure areas. A definite seasonal difference was observed in Korea. In summer and fall, time of wetness was higher than in other seasons. Because of short exposure period (12 months), significant corrosion trends depending upon materials and exposure corrosion environments were not revealed even though increased mass loss and decreased corrosion rate by exposure time.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2004년도 학술대회지
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• pp.356-359
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• 2004

Above all Ni-alloys Inconel 625 is used widely in plate of welding structural materials such as turbine case, a combustor of liner. In general, weldability of Inconel 625 is not well because of poorly liquids of weld metal also it have a broken probability oj the welding crack. In case of FCAW weld process, it is not easy to develope of welding materials, because it is possible only fillet welding at view position of look down except for butt welding. But recently, though it is more used by FCAW process, owing to welding materials worked at the vertical position. the study for FCAW weld of Inconel 625 is actively not yet worked. In this study, the weldability and weld characteristics(mechanical characteristics, corrosive property) of Inconel 625 are considered in FC4W weld associated with the several shielding gases$80\%Ar\;+\;20\%\;CO_2,\;50\%Ar\;+\;50\%\;CO_2,\;100\%\;CO_2$ in viewpoint of welding productivity. The results of impact test are follows; It was evaluated 70J at shielding gase of $100\%\;CO_2$, and obtained about 35J at the other shielding gases. If it was used for parts be required the impact value at the extremely low temperature, it is expected to have the advantage of using the $100\%\;CO_2$ shield gase than the others.

• Corrosion Science and Technology
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• 제13권5호
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• pp.178-185
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• 2014

Alloy 617 is considered as a candidate Ni-based superalloy for the intermediate heat exchanger (IHX) of a very high-temperature gas reactor (VHTR) because of its good creep strength and corrosion resistance at high temperatures. Helium is used as a coolant in a VHTR owing to its high thermal conductivity, inertness, and low neutron absorption. However, helium inevitably includes impurities that create an imbalance in the surface reactivity at the interface of the coolant and the exposed materials. As the Alloy 617 has been exposed to high temperatures at $950^{\circ}C$ in the impure helium environment of a VHTR, the degradation of material is accelerated and mechanical properties decreased. The high-temperature strength, creep, and corrosion properties of the structural material for an IHX are highly important to maintain the integrity in a harsh environment for a 60 year period. Therefore, an alloy superior to alloy 617 should be developed. In this study, the mechanical and high-temperature corrosion properties for Ni-Cr alloys fabricated in the laboratory were evaluated as a function of the grain boundary strengthening and alloying elements. The ductility increased and decreased by increasing the amount of Mo and Cr, respectively. Surface oxide was detached during the corrosion test, when Al was not added to alloy. However the alloy with Al showed improved oxide adhesive property without significant degradation and mechanical property. Aluminum seems to act as an anti-corrosive role in the Ni-based alloy.

• 한국산학기술학회논문지
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• 제19권5호
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• pp.551-556
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• 2018

대부분의 용융 아연 도금 설비에 사용되고 있는 소재는 SM45C(기계구조용 탄소강, KS규격)으로, 주로 저렴한 가격적인 측면에 의해 사용되고 있다. 용융 아연 도금의 특성상 해당 용탕에서 발생되어 올라오는 Zn Fume과 고온의 열에 의한 도금 설비의 산화가 발생되고 있으며 현재 용융 아연 도금 설비의 교체 주기의 시기는 6개월으로 많은 시간과 설비 비용이 낭비 되어오고 있다. 이에 본 연구에서는 다양한 소재들(Inconel625, STS304, SM45C)을 이용하여 고온과 Zn Fume 환경에서 강제로 산화 시켜 각각의 부식성을 확인하고 비교 분석하였으며, 각 소재들의 용융 아연 도금 현장 설비에 적용 가능성을 파악하고자 진행하였다. 강제 산화 실험은 650도의 대기로 내에 Zn 용탕을 두고, Ar 가스를 용탕 내에서 직접 버블링하여 Zn fume를 발생시켜 고온, Zn fume에 의한 부식을 행하는 실험을 하였다. 30일 후 Sample들을 꺼내어 표면의 산화층을 EDS, SEM으로 확인하고, 동전위분극 시험을 이용하여 부식성을 비교 분석하였다.

• 폴리머
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• 제34권5호
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• pp.405-409
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• 2010

내부식성이 우수한 기능기를 함유하는 새로운 졸-젤 전구체를 합성하고 이를 함유하는 유무기 하이브리드 코팅 조성물을 제조하였다. 코팅 조성물에는 통상의 졸-젤 전구체로 tetraethoxysilane을 사용하였고 비스페놀 A 타입의 에폭시를 실란화합물로 개질하였으며, 졸-젤 반응을 위하여 물과 HCl을 촉매로 사용하였다. 각 조성물은 졸-젤 전구체의 종류, 함량 등을 변화하여 다양한 코팅 조성물을 제조하였고 iron 기판위에 딥코팅하여 열경화하였다. 코팅된 iron 기판의 내부식성을 평가하기 위하여 염수분무시험과 전기화학적 임피던스 분광법을 사용하였는데, 내부식성 기능기를 함유한 유무기 하이브리드 코팅재가 일반적인 하이브리드 코팅재에 비해 매우 향상된 내부식성을 나타냄을 확인할 수 있었다. 내부식성 기능기를 함유한 코팅재의 경우, 0.1 M NaCl에서 500시간 이상 초기의 임피던스를 유지하는 반면, 일반적인 코팅재는 24시간 이후에 임피던스가 감소하는 것을 관찰할 수 있었다.

• 한국재료학회지
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• 제14권11호
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• pp.813-820
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• 2004

The electrolytic reduction of spent oxide fuel involves the liberation of oxygen in a molten LiCl electrolyte, which is a chemically aggressive environment that is very corrosive for typical structural materials. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Haynes 263, 75, and Inconel X-750, 718 in molten salt of $LiCl-Li_{2}O$ under oxidation atmosphere was investigated at $650^{\circ}C\;for\;72\sim360$ hours. At $3\;wt\%\;of\;Li_{2}O$, Haynes 263 alloy showed the highest corrosion resistance among the examined alloys, and up to $8\;wt\%\;of\;Li_{2}O$, Haynes 75 exhibited the highest corrosion resistance. Corrosion products were formed $Li(Ni,Co)O_2,\;LiNiO_2\;and\;LiTiO_2\;and\;Cr_{2}O_3$ on Haynes 263, $Cr_{2}O_3,\;NiFe_{2}O_4,\;LiNiO_2,\;Li_{2}NiFe_{2}O_4,\;Li_{2}Ni_{8}O_10$ and Ni on Haynes 75, $Cr_{2}O_3,\;(Al,Nb,Ti)O_2,\;NiFe_{2}O_4,\;and\;Li_{2}NiFe_{2}O_4$ on Inconel X-750 and $Cr_{2}O_3,\;NiFe_{2}O_4\;and\;CrNbO_4$ on Inconel 718, respectively. Haynes 263 showed local corrosion behavior and Haynes 75, Inconel X-750, 718 showed uniform corrosion behavior.

• 한국재료학회지
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• 제15권3호
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• pp.155-160
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• 2005

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 very corrosive fir typical structural materials. So, it is essential to choose the optimum material f3r the process equipment handling molten salt. In this study, the corrosion behavior of Al-Y coated Haynes 263 in a molten salt of $LiCl-Li_2O$ under oxidation atmosphere was investigated at $650^{\circ}C$ for $72\~168$ hours. The corrosion rate of Al-Y coated Haynes 263 was low while that of bare Haynes 263 was high in a molten salt of $LiCl-Li_2O$. Al-Y coated Haynes 263 improved the corrosion resistance better than bare Haynes 263 alloy. An Al oxide layer acts as a protective film which Prohibits Penetration of oxygen. Corrosion Products were formed $Li(Ni,Co)O_2$ and $LiTiO_2$ on bare Haynes 263, but $LiAlO_2,\;Li_5Fe_5O_8\;and\;LiTiO_2$ on Al-Y coated Haynes 263.

• 한국재료학회지
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• 제16권9호
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• pp.557-563
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• 2006

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. So, it is essential to choose the optimum material for the process equipment handling molten salt. In this study, corrosion behavior of Inconel 713LC, MA 754, X-750 and 718 in the molten salt $LiCl-Li_2O$ under an oxidizing atmosphere was investigated at $650^{\circ}C$ for $72{\sim}216$ hours. Inconel 713LC alloy showed the highest corrosion resistance among the examined alloys. Corrosion products of Inconel 713LC were $Cr_2O_3,\;NiCr_2O_4$ and NiO, and those of Inconel MA 754 were $Cr_2O_3\;and\;Li_2Ni_8O_{10}$ while $Cr_2O_3,\;NiFe_2O_4\;and\;CrNbO_4$ were produced from Inconel 718. Also, corrosion products of Inconel X-750 were found to be $Cr_2O_3,\;NiFe_2O_4\;and\;(Cr,Nb,Ti)O_2$. Inconel 713LC showed local corrosion behavior and Inconel MA 754, 718, X-750 showed uniform corrosion behavior.

• 한국결정성장학회지
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• 제16권3호
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• pp.121-126
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• 2006

HVOF thermal spray coating of Co-alloy T800 is progressively replacing the classical hard coatings such as chrome plating because of the very toxic $Cr^{6+}$ ion known as carcinogen causing lung cancer. For the study of the possibility of replacing of chrome plating, the wear properties of HVOF Co-alloy T800 coatings are investigated using the reciprocating sliding tester both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$. The possibility as durability improvement coating is studied for the application to the high speed spindles vulnerable to frictional heat and wear. Wear mechanisms at the reciprocating sliding wear test are studied for the application to the systems similar to the sliding test such as high speed spindles. Wear debris and frictional coefficients of T800 coatings both at room and at an elevated temperature of $1000^{\circ}F\;(538^{\circ}C)$ are drastically reduced compared to those of non-coated surface of parent substrate Inconel 718. This study shows that the coating is recommendable for the durability improvement coatings on the surfaces vulnerable to frictional heat. The sliding surfaces are weared by the mixed mechanisms such as oxidative wear, abrasion by the sliding ball slurry erosion by the mixture of solid particles and small drops of the melts and semi-melts of the attrited particles cavitation by the relative motions among the coating, sliding ball, the melts and semi-melts. and corrosive wear. The oxide particles and the melts and semi-melts play roles as solid and liquid lubricant reducing the wear and friction coefficient.