• Corrosion Science and Technology
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• 제9권6호
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• pp.317-324
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• 2010

Marine transportation by ships is characterized by remote, large-volume and lower rates than the others carry system. Ships account for over 80% of all international trading, and marine transportation is an internationally competitive, strategic, and great national important industry. The construction of larger and faster ships has brought about many problems such as cavitations and erosion corrosion. Cavitations and erosion corrosion make damages on materials and leads to break down members due to continuous physical contacts with shock waves and fluids from the generation and extinction of air bubbles in sea water vortex. The steel used for ship constructions was spray-coated with Al wire, and additionally sealed with fluorine silicone sealing material. Results of experiment, corrosion resistance of sealed thermal spray coating was improved, however in cavitation resistance, the large effect was not appeared. Accordingly, this study applied for thermal spray coating to provide better electrochemical characteristics and corrosion resistance in marine environment.

• 한국표면공학회지
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• 제40권2호
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• pp.82-90
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• 2007

Crevice corrosion is the accelerated attack occurred in the occluded cell under a crevice on the metal surface. Crevice corrosion behaviors of nickel-based alloys such as Alloy 600 and Alloy 690 were investigated in acidic solution with different chloride ion concentrations. Tests were carried out using the specially designed crevice cell with a very narrow Luggin capillary assembly to measure the potential inside the crevice. It is believed that crevice corrosion in active/passive system like nickel-based alloys has much to do with the properties of passive film and its repassivation characteristics, investigated by the capacitance measurement and by the abrading electrode technique, respectively. An attempt was made to elucidate the relationship between crevice corrosion behaviors, properties of passive film and its repassivation kinetics. Results showed that repassivation rate parameter $n1{\leq}0.6$ and/or $n2{\leq}0.5$ indicated the possible occurrence of crevice corrosion.

• 한국산업융합학회 논문집
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• 제24권5호
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• pp.517-523
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• 2021

In this study, in the selection of materials for the elements of a small plant, those with high resistance to corrosion are selected and the material properties of coatings for corrosion prevention are evaluated. In addition, corrosion characteristics and material analysis were performed on the welded part, and the hardness characteristics of the welded part, heat-affected part, and the base metal were evaluated. In the case of the post-weld-heat-treated(PWHT) specimen, the corrosion resistance of STS 316 was lower than that of the specimen without the PWHT due to the formation of intergranular carbide. As a result of evaluating the distribution of the hardness of the weld before and after the PWHT, the hardness of the specimen after the PWHT increased by about 20 Hv. As a result of the corrosion test on the welded specimen, the weight loss tended to increase as the time increased. In the case of the PWHT specimen, the corrosion resistance tended to be significantly lower than that of the specimen without PWHT due to the formation of intergranular carbide.

• 한국표면공학회지
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• 제57권3호
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• pp.140-154
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• 2024

As the trend towards miniaturization in semiconductor integration process, the limitations of interconnection metals such as copper, tungsten have become apparent, prompting research into the emergence of new materials like cobalt and emphasizing the importance of studying the corresponding process conditions. During the chemical mechanical polishing (CMP) process, corrosion inhibitors are added to the slurry, forming passivation layers on the cobalt surface, thereby playing a crucial role in controlling the dissolution rate of the metal surface, enhancing both removal rate and selectivity. This review investigates the understanding of the cobalt polishing process and examines the characteristics and behavior of corrosion inhibitors, a type of slurry additive, on the cobalt surface. Among the corrosion inhibitors examined, benzotriazole (BTA), 1,2,4-triazole (TAZ), and potassium oleate (PO) all improved surface characteristics through their interaction with cobalt. These findings provide important guidelines for selecting corrosion inhibitors to optimize CMP processes for cobalt-based semiconductor materials. Future research should explore combinations of various corrosion inhibitors and the development of new compounds to further enhance the efficiency of semiconductor processes.

• 수산해양기술연구
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• 제24권4호
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• pp.164-171
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• 1988

Recently with the rapid development in marine and shipbuilding industries such as marine structures, ships and chemical plants, it takes much interest in the study of corrosion fatigue characteristics that was close up an important role in mechanical design. In this study, characteristics of corner crack propagation on the base metal and heat affected zone of 5086 Al-Alloy was tested by using of a rotary bending fatigue tester and was investigated under the environments of specific resistance, $\rho$=25$\Omega$ cm and air. The corrosion fatigue crack initiation and corrosion fatigue life sensitivity were quantitatively inspected for 5086 Al-Alloy in the specific resistance, $\rho$=25$\Omega$ cm. Main results obtained are as follows: (1) The corrosion sensitivity of heat affected zone under specific resistance, $\rho$=25$\Omega$cm shows approximately 1.69~2.22 and corrosion sensitivity of base metal is more susceptible than that of heat affected zone. (2) The corrosion fatigue life sensitivity on heat affected zone decreases eminently than that of initial corrosion fatigue crack. (3) The characteristics of quarter elliptical corner crack propagation shows that depth crack is more grown than surface crack at crack initiation, but the surface crack is more propagated than depth crack as the crack propagation is increased. (4) The surface crack and depth crack growth on heat affected zone by softness show delayed phenomenon than that of base metal.

• Journal of Advanced Marine Engineering and Technology
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• 제26권1호
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• pp.99-107
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• 2002

Recently all kinds of structural materials are subjected to the severe corrosive environment. Especially corrosion problems of heat exchanger such as galvanic corrosion, erosion and cavitation raised by both contaminated solution and high velocity of fluid to increase cooling effect of heat exchanger have been frequently reported in these days. In this study two kinds of sheet materials and five kinds of tube materials are used for galvanic corrosion characteristics and their corrosion current density calculation. The tube materials having the most galvanic corrosion resistance between tube and sheet of heat exchanger were Al Brass(68700) and Al Brass(C6872TS) and although Ti tube predominantly indicated the highest individual corrosion resistance among those five tube materials. it appeared that Ti tube can be allowed as sheet materials to get galvanic corrosion easily. However it is considered that Cu-Ni tube materials is not only easy to produce galvanic corrosion significantly between tube and sheet regardless of kinds of sheet materials but also is appeared considerably its own high corrosion current density

• Corrosion Science and Technology
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• 제7권4호
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• pp.201-207
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• 2008

$CO_2$ corrosion product scales formed on 13 Cr tubing steel in autoclave and in the simulated corrosion environment of oil field are investigated in the paper. The surface and cross-section profiles of the scales were observed by scanning electron microscopy (SEM), the chemical compositions of the scales were analyzed using energy dispersion analyzer of X-ray (EDAX), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) to confirm the corrosion mechanism of the 13 Cr steel in the simulated $CO_2$ corrosion environment. The results show that the corrosion scales are formed by the way of fashion corrosion, consist mainly of four elements, i.e. Fe, Cr, C and O, and with a double-layer structure, in which the surface layer is constituted of bulky and incompact crystals of $FeCO_3$, and the inner layer is composed of compact fine $FeCO_3$ crystals and amorphous $Cr(OH)_3$. Because of the characteristics of compactness and ionic permeating selectivity of the inner layer of the corrosion product scales, 13 Cr steel is more resistant in $CO_2$ corrosion environment.

• Korean Chemical Engineering Research
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• 제61권3호
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• pp.419-425
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• 2023

본 논문은 상용 바이오매스 발전소 가동 조건에서 열교환기 튜브의 고온 부식 특성 분석 결과를 보고하였다. 3종의 상용 열교환기 튜브(SA213T12, SA213T22, SA213T91) 및 열교환기 튜브의 표면 온도 조절이 가능하도록 자체 설계된 고온 부식 평가 장치를 사용하였으며, 약 300시간 동안 다양한 온도 및 가동 조건에서 고온 부식 실험을 수행하였다. 열교환기 튜브 소재에 따른 온도별 고온 부식 특성을 객관적으로 분석하기 위해서 국제표준(ISO 8407)에 입각하여 부식생성물을 제거 후 고온 부식 실험 전후의 튜브 시편 무게 변화량을 산출하였다. 이를 통해 최종적으로 튜브 시편의 평균 두께 감육량 및 감육 속도를 도출하였으며, 전자현미경(FE-SEM) 및 에너지분산형 분광분석법(EDS)을 이요하여 튜브 시편의 표면과 단면의 부식 상태를 분석하였다. 본 연구 결과, 상용 열교환기 소재의 구성 성분 중 크롬과 니켈의 함량이 증가할수록 소재의 고온 부식 특성이 우수하며, 표면 온도가 증가할수록 고온 부식이 촉진되는 것을 확인하였으며, 열교환 온도 조건에 따른 열교환기 튜브 교체주기를 예측할 수 있었다.

• 한국자동차공학회논문집
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• 제13권3호
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• pp.17-23
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• 2005

In this study, the high strength and superior toughness spring steels as the suspension material, used for automobile and railroad industries were utilized to carry out the following investigations. Corrosion times were controlled in 7, 14,30 and 60days to examine the relation between corrosion pit and compressive residual stress in the static corrosion environment after shot peened. And then corrosion current and corrosion potential were measured for every 24 hours to investigate the corrosion mechanism. Shot peened material shows the low or rate of corrosion current as compared with unpeened material. In case of hot peened material which has the highest residual stress, it has a low corrosion current density.

• Journal of Advanced Marine Engineering and Technology
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• 제17권3호
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• pp.42-49
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• 1993

Recently, because the lubricating oil showed a tendency to be emulsified and oxidized by high speed, high output and the extension of maintenance & conservation of marine engine, the cavitation erosion-corrosion at such an environment became a big problem on effective performance of engine. Therefore, there was a need to study the behavior and protection of erosion-corrosion damage, and then applied inhibitor to a protective method of cavitation erosion- corrosion damage. At this time, test environments were marine lubricating oil & various emulsified oil that mixed distilled water and sea water etc., and also used 20KHz, 24.mu.m piezoelectric vibrator as an experimental apparatus of cavitation erosion. With this apparatus, we investigated an influence of the emulsified oil on characteristics of erosion-corrosion and protection for erosion-corrosion by inhibitor at slide bearing metals.