Corrosion Cost and Corrosion Map of Korea -Based on the Data From 2005 to 2010

( Y. S. Kim ),( H. K. Lim ),( J. J. Kim ),( W. S. Hwang ),( Y. S. Park ) 한국부식방식학회(구 한국부식학회) 2011 Corrosion Science and Technology Vol.10 No.2

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.

스테인리스 강의 부식 측정방법의 이용과 전망

최용선(Yongseon Choi),이재원(Jaewon Lee),박은옥(Eunoak Park),이기영(Kiyoung Lee) 한국표면공학회 2021 한국표면공학회지 Vol.54 No.6

As the number of cases of performance degradation owing to corrosion of plant during processing in industries increases, the cost of maintaining industrial factory is increasing year by the year. Most of the materials of the facilities are consist of stainless steel (SS) such as austenite SS, ferrite SS, martensite SS, and duplex SS. Among them austenite SS is cheap and has excellent corrosion resistance and heat resistance. Corrosion is the consumption and change of metals by altering chemical and electrical reactions. The types of SS corrosion include pitting corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking, and thermal corrosion. The corrosion of SS is not only investigated various environmental factors but also the measurement of the corrosion rate. Therefore, it aims to understand comprehensive corrosion rates in various environments using qualitative, quantitative and electrochemical methods.

Uniformity of Droplet of Eutectic NaCl-MgCl2 System for Corrosion Test of Coating Layer

Wonseok Lee,Wonseok Yang,Jihun Kim,Hyeongbin Kim,Taeho Jang,Sungyeol Choi 한국방사성폐기물학회 2023 한국방사성폐기물학회 학술논문요약집 Vol.21 No.1

Corrosion-related challenges remain a significant research topic in developing next-generation Molten Salt Reactors (MSRs). To gain a deeper understanding of preventing corrosion in MSRs, previous studies have attempted to improve the corrosion resistance of structural alloys by coating surfaces such as alumina coating. To conduct a corrosion test of coating alloys fully immersed in molten salt, it’s important to ensure that the coating application process is carefully carried out. Ideally, coating all sides of the alloy is necessary to avoid gaps like corners of the alloy, while only applying a one-sided coating alloy can lead to galvanic corrosion with the base metals. Using the droplet shape of eutectic salt applied to only one side of the coating alloy would avoid these problems in conventional corrosion immersion tests, as corrosion would occur solely on the coating surface. Although the droplet method for corrosion tests cannot fully replicate corrosion in the MSRs environment, it offers a valuable tool for comparing and evaluating the corrosion resistance of different coating surfaces of alloys. However, the surface area is important due to the effect of diffusion in the corrosion of alloy in molten salt environments, but it is difficult to unify in the case of droplet tests. Therefore, understanding the droplet-alloy properties and corrosion mechanism is needed to accurately predict and analyze these test systems’ behavior highlighting unity for corrosion tests of different coating surfaces of alloys. To analyze the molten salt droplet behavior on various samples, pelletized eutectic NaCl-MgCl2 was prepared as salt and W-, Mo-coating, and base SS316 as samples. At room temperature, the same mass of pelletized eutectic NaCl-MgCl2 was placed on different samples under an argon atmosphere and heated to a eutectic point of 500°C in a furnace. After every hour, the molten droplets were hardened by rapid cooling at room temperature outside the furnace. The mass loss of salts and the contact area of the samples were measured by mass balance and SEM. The shape, surface area to volume ratio, and evaporation of the droplets of NaCl-MgCl2 per each coating sample and hour were analyzed to identify the optimal mass to equalize the contact coating surface of alloys with salts. Furthermore, We also analyzed whether their results reached saturation of corrosion products through ICP-MS. This will be significant research for the uniformity of the liquid-drop shape corrosion test of the coating sample in molten eutectic salts.

Magnesium Corrosion Mechanisms

Song, G. L.,Atrens, A. 한국부식방식학회 2002 Corrosion Science and Technology Vol.31 No.2

This paper provides an overview of the corrosion mechanisms of magnesium alloys based on our recent research and the literature. Magnesium is a very reactive metal. Thus galvanic cmosian is very important. Galvanic corrosion is associated with (1) impurities, particularly Fe, Ni & Cu (2) second phases, eg β, and (3) coupling with a less active metal. Magnesium alloys exposed without galvanic coupling have a corrosion resistance that, in general, is not as good as that of aluminium alloys. When magnesium is passive, then the corrosion rates are low. But the range of environmental conditions for passivity for magnesium is less than for aluminium; ie passive films are not very stable. Corrosion is typically important as localised corrosion such as pitting & SCC. There is the expectation that SCC failures will increase with increased use of Mg alloys in load bearing applications. Corrosion of AZ91 is by "pitting" in IN NaCI. The corrosion potential, Ecorr is above the "pitting" potential. Corrosion of cast AZ91 has the following morphologies, (1) preferential attack of primary α, (2) preferential attack of eutectic α & undermining of β. The β phase is more stable than α, and β is a better cathode. There is corrosion protection and low corrosion rates if there is a significant fraction of finely divided continuous β. Otherwise β accelerates corrosion. Corrosion acceleration is significant if there are large blocks of interconnected β. Corrosion acceleration may be small if β is small and finely divided.

부식 환경에 따른 출토 청동 유물의 부식 특성

장준혁,배고운,정광용 국립문화재연구원 2020 헤리티지:역사와 과학 Vol.53 No.1

In excavated bronze artifacts, corrosion products of various shapes and colors are observed due to multiple corrosion factors coexisting in the burial environment, and these corrosion products can constitute important data not only in terms of long-term corrosion-related information, but also in connection with preservation of artifacts. As such, scientific analysis is being carried out on the corrosion layer and corrosion products of bronze artifacts, and the corrosion mechanism and the characteristics of corrosion products elucidated, which is essential for interpreting the exposed burial environment and its association with corrosion factors inside the burial environment. In this study, after classifying excavated bronze artifacts according to alloy ratio and fabrication technique, comprehensive analysis of the surface of corrosion artifacts, corrosion layer, and corrosion products was carried out to investigate the corrosion mechanism, formation process of the corrosion layer, and characteristics of corrosion products. The study designated two groups according to alloy ratio and fabrication technique. In Group 1, which involved a Cu-Sn-Pb alloy and had no heat treatment, the surface was rough and external corrosion layers were formed on a part, or both sides, of the inside and the outside, and the surface was observed as being green or blue. α+δ phase selection corrosion was found in the metal and some were found to be concentrated in an empty space with a purity of 95 percent or more after α+δ phase corrosion. The Cu-Sn alloy and heat-treated Group 2 formed a smooth surface with no external corrosion layer, and a dark yellow surface was observed. In addition, no external corrosion layer was observed, unlike Group 1, and α corrosion was found inside the metal. In conclusion, it can be seen that the bronze artifacts excavated from the same site differ in various aspects, including the formation of the corrosion layer, the shape and color of the corrosion products, and the metal ion migration path, depending on the alloy ratio and fabrication technique. They also exhibited different corrosion characteristics in the same material, which means that different forms of corrosion can occur depending on the exposure environment in the burial setting. Therefore, even bronze artifacts excavated from the same site will have different corrosion characteristics depending on alloy ratio, fabrication technique, and exposure environment. The study shows one aspect of corrosion characteristics in specific areas and objects; further study of corrosion mechanisms in accordance with burial conditions will be required through analysis of the corrosive layer and corrosive product characteristics of bronze artifacts from various regions.

무기성 PCM 혼합물에 의한 에너지저장용기재료의 방식특성

송희열,성현숙 건국대학교 산업기술연구원 2000 건국기술연구논문지 Vol.25 No.-

This is the experimental study on the effects of PCM (Phase Change Material) mixture and anti-corrosion additives on the metal for energy storage container. Aluminum, copper, steel, and SUS 304 were used as metal materials. Experiments were carried out at constant temperature above the melting point of the corresponding PCM submerging test metal specimens into the PCM mixture and anti-corrosion additives contained PCM mixture for 30 days. Aluminum showed the significant corrosion against all the PCM mixture and copper was not corroded against DSP only as the PCM mixture. Steel was corroded against GS with rust, ST with black color and not corroded against DSP, SA. SUS 304 seems to be corrosion-resistant material due to the anti-corrosiveness and no decrease of weight. Hexamethylene tetramine as anti-corrosion additive showed unsuitable anti-corrosion effects on aluminum against all the PCM mixture, but other additives showed suitable one against ST only, Mono quarternary ammonium chloride seems to be suitable additive for the anti-corrosion on copper against GS, DSP, SA and especially all the anti-corrosion effects on copper against DSP. N-methymorpholine and adipic acid showed insignificant anti-corrosion effects against PCM mixture except DSP and the other additives showed unsuitable anti-corrosion effects. All the anti-corrosion additives showed good anti-corrosion effects on SUS 304.

해양 금속재료의 부식속도와 방식전류에 미치는 유속의 영향

이승준 ( Seung Jun Lee ),한민수 ( Min Su Han ),장석기 ( Seok Ki Jang ),김성종 ( Seong Jong Kim ) 한국부식방식학회(구 한국부식학회) 2015 Corrosion Science and Technology Vol.14 No.5

In spite of highly advanced paint coating techniques, corrosion damage of marine metal and alloys increase more and more due to inherent micro-cracks and porosities in coatings formed during the coating process.Furthermore, flowing seawater conditions promote the breakdown of the protective oxide of the materials introducing more oxygen into marine environments, leading to the acceleration of corrosion. Various corrosion protection methods are available to prevent steel from marine corrosion. Cathodic protection is one of the useful corrosion protection methods by which the potential of the corroded metal is intentionally lowered to an immune state having the advantage of providing additional protection barriers to steel exposed to aqueous corrosion or soil corrosion, in addition to the coating. In the present investigation, the effect of flow velocity was examined for the determination of the optimum corrosion protection current density in cathodic protection as well as the corrosion rate of the steel. It is demonstrated from the result that the material corrosion under dynamic flowing conditions seems more prone to corrosion than under static conditions.

Investigation of Volumetric Effect of Coarse Aggregate on Corroding Steel Reinforcement at the Interfacial Transition Zone of Concrete

Raja Rizwan Hussain,Tetsuya Ishida 대한토목학회 2011 KSCE JOURNAL OF CIVIL ENGINEERING Vol.15 No.1

Corrosion is an electrochemical process which requires electrolyte for the occurrence of corrosion reaction. Therefore it is necessary to calculate the effective corrosion rate with reference to the saturated area of concrete only when it comes to corrosion of steel reinforcement embedded in concrete. Theoretically and numerically the saturated area depends on the capillary zone porosity,gel zone porosity and their respective degree of saturation in the aggregate free volume of concrete which is a heterogeneous material in nature. This makes it important to deeply understand the effect of aggregate on corrosion in concrete. Investigation was carried out to find the effect of coarse aggregate volume on the corrosion rate and potential of reinforcement steel in concrete. The initiative for this research came from the observation that the interfacial transition zone around the steel bar in concrete is surrounded primarily by paste only and hence the coarse aggregate volume should not influence the corrosion rate principally. Also there are chances that some fine aggregate could be present in the vicinity of steel bar surface being finer than coarse aggregate which may affect the corrosion rate. The previous research data in this field was found to be limited and has a difference of opinion. Therefore, these factors have been investigated in this research. Prismatic concrete and mortar specimens were cast and their corrosion potential values were compared with each other to find the effect of the volume of coarse aggregate on corrosion. The experiment results showed that the effect of the volume of coarse aggregate on corrosion potential is not significant since the area around the steel bar especially in the case of deformed steel is mostly surrounded by paste only. The corrosion potential values obtained in the case of mortar and concrete specimens showed same averaged magnitude. This fact was further strengthened by measuring the corrosion mass loss and resulting corrosion rate in the two cases. Furthermore, in the light of experiment results obtained in this research, the numerical FEM model DuCOM developed by our research group at the University of Tokyo, Japan incorporating the effect of aggregate on corrosion rate and potential of corroding steel in concrete undertaken in the past has been successfully enhanced and verified in this research.

Poly(o-anisidine) coatings on brass: Synthesis, characterization and corrosion protection

Sudeshna Chaudhari,A.B. Gaikwad,P.P. Patil 한국물리학회 2009 Current Applied Physics Vol.9 No.1

Poly(o-anisidine) (POA) coatings were synthesized on brass by electrochemical polymerization of o-anisidine in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The corrosion protection aspects of POA coatings on brass in aqueous 3% NaCl solution were investigated by potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the POA coating has ability to protect the brass against corrosion. The corrosion potential was about 0.204 V versus SCE more positive for the POA coated brass than that of uncoated brass and reduces the corrosion rate of brass almost by a factor of 800. The corrosion behavior of the POA coatings was also investigated by EIS through immersion tests performed in aqueous 3% NaCl solution. The evolution of the impedance parameters with the immersion time was studied and the results show that the POA acts as a protective coating on brass against corrosion in 3% NaCl solution. The water uptake and delamination area were also determined to further support the corrosion protection performance of the POA coating. Poly(o-anisidine) (POA) coatings were synthesized on brass by electrochemical polymerization of o-anisidine in aqueous salicylate solution by using cyclic voltammetry. These coatings were characterized by cyclic voltammetry, UV–visible absorption spectroscopy, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). The corrosion protection aspects of POA coatings on brass in aqueous 3% NaCl solution were investigated by potentiodynamic polarization technique and electrochemical impedance spectroscopy (EIS). The potentiodynamic polarization measurements show that the POA coating has ability to protect the brass against corrosion. The corrosion potential was about 0.204 V versus SCE more positive for the POA coated brass than that of uncoated brass and reduces the corrosion rate of brass almost by a factor of 800. The corrosion behavior of the POA coatings was also investigated by EIS through immersion tests performed in aqueous 3% NaCl solution. The evolution of the impedance parameters with the immersion time was studied and the results show that the POA acts as a protective coating on brass against corrosion in 3% NaCl solution. The water uptake and delamination area were also determined to further support the corrosion protection performance of the POA coating.

탄소강 및 해드필드강의 파이프 조관에 따른 침식부식 거동에 대한 비교연구

김성진,윤덕빈,박진성,이상철,최종교,황중기 한국부식방식학회 2022 Corrosion Science and Technology Vol.21 No.3

Erosion-corrosion behaviors of Hadfield steel under a neutral aqueous environment with fine SiO2 particles were examined and compared with those of conventional carbon steel. A range of electrochemical experiments (potentiodynamic polarization, linear polarization, and impedance), immersion test, and slurry pot test (i.e., erosion-corrosion test) were performed. Results showed that the Hadfield steel composed of austenitic matrix with (Fe,Mn)-based carbide had lower corrosion potential and higher corrosion current density than carbon steel with a typical ferrite/pearlite structure. In addition, pipe forming increased total corrosion rates (i.e., pure corrosion and erosion-enhanced corrosion rates). Nevertheless, the erosion-corrosion rate of Hadfield steel was much smaller. Morphological observation showed that local damage in the form of a crater by erosion-corrosion was more noticeable in carbon steel. The higher resistance of Hadfield steel to erosion-corrosion was attributed to its lower total erosion rates (i.e., pure erosion and corrosion-enhanced erosion rates) highly depending on surface hardness. This study suggests that Hadfield steel with higher resistances to flowing erosion-corrosion in an aqueous environment can be applied widely to various industrial fields.