Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.23
S. Bhang, Hyunjoong Kim, A. Shin, Jinhwan Park
{"title":"The Paint Prepared Using 2D Materials: An Evaluation of Heat Dissipation and Anticorrosive Performance","authors":"S. Bhang, Hyunjoong Kim, A. Shin, Jinhwan Park","doi":"10.14773/CST.2020.19.1.23","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.23","url":null,"abstract":"","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44331273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.8
T. Thai, A. T. Trinh, G. V. Pham, T. Pham, H. N. Xuân
Hexavalent chromium compounds (Cr(VI)) have been effectively applied for corrosion protection of aluminum alloy in various processes such as conversion coating, sealing or rinsing for anodization and in the primer laye r... [1-3]. Nevertheless, their cancerous risk and their toxicity for environment required to restrict or eliminate their future use. Significant efforts have been proceeded in last decade to find environmentally friendly alternative inhibitors [4]. Among them, the organic compounds, including the heterocyclic compounds, organic phosphates or carboxylates... and sometimes the synergistic combinations of organic inhibitors have exhibited the high corrosion inhibition effect for the aluminum alloy 2024-T3 surface [5-8]. This effectiveness is based on the formation of a protective barrier film on the surface to avoid the diffusion of oxygen and aggressive species at the metallic surface. The formed film is on the basis of the electrostatic and chemical adsorption of organic molecules on the metallic surface. However, suffer from the fact that this film is normal unstable caused by the highly reversible adsorption of organic inhibitor, limiting the longterm protection for the metal [9]. The inhibition behavior of inorganic substances such as metal cations toward to the corrosion of aluminum alloys has been variously studied. The lanthanides cations (La, Ce, Y, Pr, Nd, Pm...) have been interested from the 1990s. It was shown that the presence of lanthanum or cerium on the aluminum surface hinder the anodic and cathodic processes [10,11]. The cerium cations gave a highest inhibition effect in comparison with other elements, this is due to the formation of the insoluble cerium hydroxide or cerium oxide film resulted by the reaction with the OH group during the cathodic process. However, in the chloride medium, composing with the mixture of Ce(OH)3, Al(OH)3 and Ce(OH)xCl3-x is relative thin for corrosion †Corresponding author: anhtruc.trinh@itt.vast.vn (Anh Truc Trinh) †Corresponding author: ttthuy@itt.vast.vn (Thu Thuy Thai) Corrosion Protection Properties of Cobalt Salt for Water-Based Epoxy Coatings on 2024-T3 Aluminum Alloy
{"title":"Corrosion Protection Properties of Cobalt Salt for Water-Based Epoxy Coatings on 2024-T3 Aluminum Alloy","authors":"T. Thai, A. T. Trinh, G. V. Pham, T. Pham, H. N. Xuân","doi":"10.14773/CST.2020.19.1.8","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.8","url":null,"abstract":"Hexavalent chromium compounds (Cr(VI)) have been effectively applied for corrosion protection of aluminum alloy in various processes such as conversion coating, sealing or rinsing for anodization and in the primer laye r... [1-3]. Nevertheless, their cancerous risk and their toxicity for environment required to restrict or eliminate their future use. Significant efforts have been proceeded in last decade to find environmentally friendly alternative inhibitors [4]. Among them, the organic compounds, including the heterocyclic compounds, organic phosphates or carboxylates... and sometimes the synergistic combinations of organic inhibitors have exhibited the high corrosion inhibition effect for the aluminum alloy 2024-T3 surface [5-8]. This effectiveness is based on the formation of a protective barrier film on the surface to avoid the diffusion of oxygen and aggressive species at the metallic surface. The formed film is on the basis of the electrostatic and chemical adsorption of organic molecules on the metallic surface. However, suffer from the fact that this film is normal unstable caused by the highly reversible adsorption of organic inhibitor, limiting the longterm protection for the metal [9]. The inhibition behavior of inorganic substances such as metal cations toward to the corrosion of aluminum alloys has been variously studied. The lanthanides cations (La, Ce, Y, Pr, Nd, Pm...) have been interested from the 1990s. It was shown that the presence of lanthanum or cerium on the aluminum surface hinder the anodic and cathodic processes [10,11]. The cerium cations gave a highest inhibition effect in comparison with other elements, this is due to the formation of the insoluble cerium hydroxide or cerium oxide film resulted by the reaction with the OH group during the cathodic process. However, in the chloride medium, composing with the mixture of Ce(OH)3, Al(OH)3 and Ce(OH)xCl3-x is relative thin for corrosion †Corresponding author: anhtruc.trinh@itt.vast.vn (Anh Truc Trinh) †Corresponding author: ttthuy@itt.vast.vn (Thu Thuy Thai) Corrosion Protection Properties of Cobalt Salt for Water-Based Epoxy Coatings on 2024-T3 Aluminum Alloy","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42720088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.16
T. Nguyen, A. S. Nguyen, T. Thai, G. V. Pham, Thi Xuan Hang To, M. Olivier
It is important to realize that benzoate was intercalated into hydrotalcite (HTC-Bz) by the co-precipitation method. In this case, acrylic coating with 0.5 wt% HTC-Bz was deposited on carbon steel using the spin coating method. Next, the HTC-Bz structure was characterized by Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). In fact, an ultraviolet vision spectroscopy (UV-Vis) was used to determine the benzoate content in HTC-Bz, and the UV absorption ability of HTC-Bz. Using electrochemical techniques, water contact angle measurement, and thermal-gravimetric analysis, we compared the protective properties before and after QUV test, hydrophobicity and the thermal stability of acrylic coating containing HTC-Bz. The obtained results showed that HTC-Bz with a plate-like structure was successfully synthesized; benzoate was intercalated into the interlayer of hydrotalcite with a concentration of 28 wt%. Additionally, it was noted that HTC-Bz has an UV absorption peak at 225 nm. In conclusion, the addition of HTC-Bz enhanced the UV stability, hydrophobicity and the thermal stability of acrylic coating.
{"title":"The Influence of Hydrotalcite Intercalated with Benzoate on UV Stability of Acrylic Coating","authors":"T. Nguyen, A. S. Nguyen, T. Thai, G. V. Pham, Thi Xuan Hang To, M. Olivier","doi":"10.14773/CST.2020.19.1.16","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.16","url":null,"abstract":"It is important to realize that benzoate was intercalated into hydrotalcite (HTC-Bz) by the co-precipitation method. In this case, acrylic coating with 0.5 wt% HTC-Bz was deposited on carbon steel using the spin coating method. Next, the HTC-Bz structure was characterized by Field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR). In fact, an ultraviolet vision spectroscopy (UV-Vis) was used to determine the benzoate content in HTC-Bz, and the UV absorption ability of HTC-Bz. Using electrochemical techniques, water contact angle measurement, and thermal-gravimetric analysis, we compared the protective properties before and after QUV test, hydrophobicity and the thermal stability of acrylic coating containing HTC-Bz. The obtained results showed that HTC-Bz with a plate-like structure was successfully synthesized; benzoate was intercalated into the interlayer of hydrotalcite with a concentration of 28 wt%. Additionally, it was noted that HTC-Bz has an UV absorption peak at 225 nm. In conclusion, the addition of HTC-Bz enhanced the UV stability, hydrophobicity and the thermal stability of acrylic coating.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41386961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.31
Kyungbae Kim, Han-Seul Kim, H. Seo, Jae‐Hun Kim
{"title":"Electrochemical and Thermal Property Enhancement of Natural Graphite Electrodes via a Phosphorus and Nitrogen Incorporating Surface Treatment","authors":"Kyungbae Kim, Han-Seul Kim, H. Seo, Jae‐Hun Kim","doi":"10.14773/CST.2020.19.1.31","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.31","url":null,"abstract":"","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41950767","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.43
Kwang-Hu Jung, Seong-Jong Kim, 정광후･김성종
In this study, the effects of KCl(s) and K2SO4(s) on the oxidation characteristics of 2.25Cr-1Mo steel were investigated for 500 h in 10O2 + 10CO2 (vol%) gas environmen at 650 °C. Oxidation kinetics were characterized by weight gain, oxide layer thickness, and fitted models for the experiment data were proposed. The fitted models presented considerable agreement with the experimental data. The oxide layer was analyzed using the scanning electron microscope, optical microscope, and energy dispersive X-ray spectroscopy. The oxidation kinetics of 2.25Cr-1Mo steel with KCl and K2SO4 coatings showed significantly different oxidation kinetics. KCl accelerated the oxidation rate very much and had linear oxidation behavior. In contrast, K2SO4 had no significant effect, which had parabolic kinetics. The oxide layer was commonly composed of Fe2O3, Fe3O4, and FeCr2O4 spinel. KCl strongly accelerated the oxidation rates of 2.25Cr-1Mo steel in the high-temperature oxidation environment. Conversely, K2SO4 had little effect on the oxidation rates.
{"title":"650 ℃의 10%O 2 +10%CO 2 가스 환경에서 2.25Cr-1Mo강의 산화특성에 미치는 KCl(s)과 K 2 SO 4 (s)의 영향","authors":"Kwang-Hu Jung, Seong-Jong Kim, 정광후･김성종","doi":"10.14773/CST.2020.19.1.43","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.43","url":null,"abstract":"In this study, the effects of KCl(s) and K2SO4(s) on the oxidation characteristics of 2.25Cr-1Mo steel were investigated for 500 h in 10O2 + 10CO2 (vol%) gas environmen at 650 °C. Oxidation kinetics were characterized by weight gain, oxide layer thickness, and fitted models for the experiment data were proposed. The fitted models presented considerable agreement with the experimental data. The oxide layer was analyzed using the scanning electron microscope, optical microscope, and energy dispersive X-ray spectroscopy. The oxidation kinetics of 2.25Cr-1Mo steel with KCl and K2SO4 coatings showed significantly different oxidation kinetics. KCl accelerated the oxidation rate very much and had linear oxidation behavior. In contrast, K2SO4 had no significant effect, which had parabolic kinetics. The oxide layer was commonly composed of Fe2O3, Fe3O4, and FeCr2O4 spinel. KCl strongly accelerated the oxidation rates of 2.25Cr-1Mo steel in the high-temperature oxidation environment. Conversely, K2SO4 had little effect on the oxidation rates.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47317603","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-02-29DOI: 10.14773/CST.2020.19.1.1
Y. Jung, S. Baik, Y. Jin
Chalk River Unidentified Deposits (CRUDs) were collected from the Korean pressurized water reactor (PWR) plant (A, B, and C) where the axial offset anomaly (AOA) occurred. AOA, also known as a CRUD-induced power shift, is one of the key issues in maintaining stable PWR plant operations. CRUDs were sampled from spent nuclear fuel rods and analyzed using an electron probe micro-analyzer (EPMA). This paper describes the characteristics of boron-deposits from the CRUDs sampled from twice-burnt assemblies from the Korean PWR. The primary coolant of a PWR contains boron and lithium. It is known that boron deposition occurs in a thick CRUD layer under substantial sub-cooled nucleate boiling (SNB). The results of this study are summarized as follows. Boron was not found at the locations where the existence was confirmed in simulated CRUDs, in other words, the cladding and CRUD boundaries. Nevertheless, we clearly observed the presence of boron and confirmed that boron existed as a lump in crystalline form. In addition, the study confirmed that CRUD existed in a crystal form with a unique size of about 10 μm.
{"title":"A Study on the Crystalline Boron Analysis in CRUD in Spent Fuel Cladding Using EPMA X-ray Images","authors":"Y. Jung, S. Baik, Y. Jin","doi":"10.14773/CST.2020.19.1.1","DOIUrl":"https://doi.org/10.14773/CST.2020.19.1.1","url":null,"abstract":"Chalk River Unidentified Deposits (CRUDs) were collected from the Korean pressurized water reactor (PWR) plant (A, B, and C) where the axial offset anomaly (AOA) occurred. AOA, also known as a CRUD-induced power shift, is one of the key issues in maintaining stable PWR plant operations. CRUDs were sampled from spent nuclear fuel rods and analyzed using an electron probe micro-analyzer (EPMA). This paper describes the characteristics of boron-deposits from the CRUDs sampled from twice-burnt assemblies from the Korean PWR. The primary coolant of a PWR contains boron and lithium. It is known that boron deposition occurs in a thick CRUD layer under substantial sub-cooled nucleate boiling (SNB). The results of this study are summarized as follows. Boron was not found at the locations where the existence was confirmed in simulated CRUDs, in other words, the cladding and CRUD boundaries. Nevertheless, we clearly observed the presence of boron and confirmed that boron existed as a lump in crystalline form. In addition, the study confirmed that CRUD existed in a crystal form with a unique size of about 10 μm.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-02-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47093927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.14773/CST.2020.19.6.302
Seong-Jong Kim, K. Jung
This study aimed to predict the pitting corrosion characteristics of AL-6XN super-austenitic steel using multiple linear regression. The variables used in the model are degree of sensitization, temperature, and pH. Experiments were designed and cyclic polarization curve tests were conducted accordingly. The data obtained from the cyclic polarization curve tests were used as training data for the multiple linear regression model. The significance of each factor in the response (critical pitting potential, repassivation potential) was analyzed. The multiple linear regression model was validated using experimental conditions that were not included in the training data. As a result, the degree of sensitization showed a greater effect than the other variables. Multiple linear regression showed poor performance for prediction of repassivation potential. On the other hand, the model showed a considerable degree of predictive performance for critical pitting potential. The coefficient of determination (R 2 ) was 0.7745. The possibility for pitting potential prediction was confirmed using multiple linear regression.
{"title":"Prediction of Pitting Corrosion Characteristics of AL-6XN Steel with Sensitization and Environmental Variables Using Multiple Linear Regression Method","authors":"Seong-Jong Kim, K. Jung","doi":"10.14773/CST.2020.19.6.302","DOIUrl":"https://doi.org/10.14773/CST.2020.19.6.302","url":null,"abstract":"This study aimed to predict the pitting corrosion characteristics of AL-6XN super-austenitic steel using multiple linear regression. The variables used in the model are degree of sensitization, temperature, and pH. Experiments were designed and cyclic polarization curve tests were conducted accordingly. The data obtained from the cyclic polarization curve tests were used as training data for the multiple linear regression model. The significance of each factor in the response (critical pitting potential, repassivation potential) was analyzed. The multiple linear regression model was validated using experimental conditions that were not included in the training data. As a result, the degree of sensitization showed a greater effect than the other variables. Multiple linear regression showed poor performance for prediction of repassivation potential. On the other hand, the model showed a considerable degree of predictive performance for critical pitting potential. The coefficient of determination (R 2 ) was 0.7745. The possibility for pitting potential prediction was confirmed using multiple linear regression.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66632888","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.14773/CST.2020.19.2.51
S. Take, Tusyoshi Otabe, Wataru Ohgake, T. Atsumi
The objective of this study was to improve properties of plasma sprayed HAp layer to titanium substrate by introducing an intermediate layer with two different methods. Before applying Zn doped HAp coating on titanium substrate, an intermediate layer was introduced by titanium plasma spray or titanium anodization. Heat treatments were conducted for some samples after titanium intermediate layer was formed. Zn doped HAp top layer was applied by plasma spraying. Three-point bending test and pull-off adhesion test were performed to determine the adhesion of Zn doped HAp coatings to substrates. Long-term credibility of Zn doped HAp plasma sprayed coatings on titanium was assessed by electrochemical impedance measurements in Hanks’ solution. It was found that both titanium plasma sprayed and titanium anodized intermediate layer had excellent credibility. Strong adhesion to the titanium substrate was confirmed after 12 weeks of immersion for coating samples with titanium plasma sprayed intermediate layer. Samples with titanium anodized intermediate layer showed good bending strength. However, they showed relatively poor resistance against pulling off. The thickness of titanium anodized intermediate layer can be controlled much more precisely than that of plasma sprayed one, which is important for practical application.
{"title":"Effect of Ti Intermediate Layer on Properties of HAp Plasma Sprayed Biocompatible Coatings","authors":"S. Take, Tusyoshi Otabe, Wataru Ohgake, T. Atsumi","doi":"10.14773/CST.2020.19.2.51","DOIUrl":"https://doi.org/10.14773/CST.2020.19.2.51","url":null,"abstract":"The objective of this study was to improve properties of plasma sprayed HAp layer to titanium substrate by introducing an intermediate layer with two different methods. Before applying Zn doped HAp coating on titanium substrate, an intermediate layer was introduced by titanium plasma spray or titanium anodization. Heat treatments were conducted for some samples after titanium intermediate layer was formed. Zn doped HAp top layer was applied by plasma spraying. Three-point bending test and pull-off adhesion test were performed to determine the adhesion of Zn doped HAp coatings to substrates. Long-term credibility of Zn doped HAp plasma sprayed coatings on titanium was assessed by electrochemical impedance measurements in Hanks’ solution. It was found that both titanium plasma sprayed and titanium anodized intermediate layer had excellent credibility. Strong adhesion to the titanium substrate was confirmed after 12 weeks of immersion for coating samples with titanium plasma sprayed intermediate layer. Samples with titanium anodized intermediate layer showed good bending strength. However, they showed relatively poor resistance against pulling off. The thickness of titanium anodized intermediate layer can be controlled much more precisely than that of plasma sprayed one, which is important for practical application.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66633003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.14773/CST.2020.19.4.224
M. Boo, Jangseok Lee, Jong-Hoon Lee
Stainless steel has excellent corrosion resistance. The drawback is that pitting occurs easily due to the concentration of chloride. In addition, corrosion of socket weld, which is structurally and chemically weaker than the other components of the pipe, occurs rapidly. Since these two phenomena overlap, pinhole leakage occurs frequently in the seawater pipe socket welds made of stainless steel at the power plants. To analyze this specific corrosion, a metallurgical analysis of the stainless steel socket welds, where the actual corrosion occurred during the power plant operation, was performed. The micro-structure and chemical composition of each socket weld were analyzed. In addition, selective corrosion of the specific micro-structure in a mixed dendrite structure comprising γ-austenite (gamma-phase iron) and δ-ferrite (iron at high temperature) was investigated based on the characteristic micro-morphology and chemical composition of the corroded area. Finally, the different corrosion stages and characteristics of socket weld corrosion are summarized.
{"title":"Selective Corrosion of Socket Welds of Stainless Steel Pipes Under Seawater Atmosphere","authors":"M. Boo, Jangseok Lee, Jong-Hoon Lee","doi":"10.14773/CST.2020.19.4.224","DOIUrl":"https://doi.org/10.14773/CST.2020.19.4.224","url":null,"abstract":"Stainless steel has excellent corrosion resistance. The drawback is that pitting occurs easily due to the concentration of chloride. In addition, corrosion of socket weld, which is structurally and chemically weaker than the other components of the pipe, occurs rapidly. Since these two phenomena overlap, pinhole leakage occurs frequently in the seawater pipe socket welds made of stainless steel at the power plants. To analyze this specific corrosion, a metallurgical analysis of the stainless steel socket welds, where the actual corrosion occurred during the power plant operation, was performed. The micro-structure and chemical composition of each socket weld were analyzed. In addition, selective corrosion of the specific micro-structure in a mixed dendrite structure comprising γ-austenite (gamma-phase iron) and δ-ferrite (iron at high temperature) was investigated based on the characteristic micro-morphology and chemical composition of the corroded area. Finally, the different corrosion stages and characteristics of socket weld corrosion are summarized.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66632840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-01-01DOI: 10.14773/CST.2020.19.4.189
Hyongjoon Lee, H. Chae, J. Cho, W. Kim, J. Jeong, Heesan Kim, Jung-Gu Kim, S. Lee
Two air vents situated on a heat transport pipe in district heating system were exposed to the same environment for 10 years. However, one air vent was more corroded than the other. It also had a hole on the top of the front-end pipe. Comparative analysis was performed for these air vents to identify the cause of corrosion and establish countermeasures. Through experimental observation of the damaged part and analyses of powders sampled from air vents, it was found that corrosion was initiated at the top of the front-end pipe. It then spread to the bottom. Energy dispersive X-ray spectroscopy results showed that potassium and chlorine were measured from the corroded product in the damaged air vent derived from rainwater and insulation, respectively. The temperature of the damaged air vent was maintained at 75 ~ 120 °C by heating water. Rainwater-soaked insulation around the front-end pipe had been hydrolyzed. Therefore, the damaged air vent was exposed to an environment in which corrosion under insulation could be facilitated. In addition, ion chromatography and inductively coupled plasma measurements indicated that the matrix of the damaged front-end pipe contained a higher manganese content which might have promoted corrosion under insulation.
{"title":"Corrosion Failure Analysis of Air Vents Installed at Heat Transport Pipe in District Heating System","authors":"Hyongjoon Lee, H. Chae, J. Cho, W. Kim, J. Jeong, Heesan Kim, Jung-Gu Kim, S. Lee","doi":"10.14773/CST.2020.19.4.189","DOIUrl":"https://doi.org/10.14773/CST.2020.19.4.189","url":null,"abstract":"Two air vents situated on a heat transport pipe in district heating system were exposed to the same environment for 10 years. However, one air vent was more corroded than the other. It also had a hole on the top of the front-end pipe. Comparative analysis was performed for these air vents to identify the cause of corrosion and establish countermeasures. Through experimental observation of the damaged part and analyses of powders sampled from air vents, it was found that corrosion was initiated at the top of the front-end pipe. It then spread to the bottom. Energy dispersive X-ray spectroscopy results showed that potassium and chlorine were measured from the corroded product in the damaged air vent derived from rainwater and insulation, respectively. The temperature of the damaged air vent was maintained at 75 ~ 120 °C by heating water. Rainwater-soaked insulation around the front-end pipe had been hydrolyzed. Therefore, the damaged air vent was exposed to an environment in which corrosion under insulation could be facilitated. In addition, ion chromatography and inductively coupled plasma measurements indicated that the matrix of the damaged front-end pipe contained a higher manganese content which might have promoted corrosion under insulation.","PeriodicalId":43201,"journal":{"name":"Corrosion Science and Technology-Korea","volume":null,"pages":null},"PeriodicalIF":0.6,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66633275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：