المؤلفون: Lu, Shihang, Zhu, Haixia, Sun, Jiahao, Gu, Tingyue, Xue, Nianting, Chen, Shiqiang, Liu, Guangzhou, Dou, Wenwen

المصدر: Journal of Materials Science & Technology; Sep2024, Vol. 194, p110-123, 14p

مصطلحات موضوعية: COPPER, MICROBIOLOGICALLY influenced corrosion, ARTIFICIAL seawater, EUTROPHICATION, SEAWATER, BIODEGRADATION

مستخلص: • Eutrophication enhances D. vulgaris planktonic growth and its sessile growth on Cu. • Cu MIC uniform corrosion and pitting increase with seawater eutrophication level. • Sessile cells on carbon steel MIC possess more cytochrome c than planktonic cells. • Cytochrome c levels in sessile and planktonic cells do not differ in Cu MIC. • Cu MIC by D. vulgaris belongs to metabolite MIC by secreted biogenic H 2 S. Seawater eutrophication increases the abundance of microbial communities and metabolic activities of microorganisms in seawater and potentially impacts microbiologically influenced corrosion (MIC). Copper as a common material in marine structures and nuclear waste containers faces serious MIC problems. This study investigated the copper MIC caused by Desulfovibrio vulgaris in anaerobic artificial seawater (ASW) with four eutrophication levels: pure ASW (PASW), oligotrophication ASW (OASW), mesotrophication ASW (MASW), and eutrophication ASW (EASW). It was found that the copper MIC increased along with the eutrophication level. The higher eutrophication led to an increase in the planktonic and Cu surface sessile D. vulgaris cell counts and H 2 S concentration in the headspace of anaerobic vials. The resultant weight loss and maximum pitting depth of copper in OASW were 2.0 and 2.4 times those in PASW, while their values in EASW were 2.8 and 4.2 times after 10 d of incubation, respectively. The experimental results combined with a bioenergetic analysis in this study indicated the copper MIC caused by D. vulgaris as belonging to biogenic H 2 S corrosion (i.e., metabolite MIC or M-MIC), which was further confirmed by the identical cytochrome c (Cyt c) (redox-active protein for extracellular electron transfer) expression levels of the planktonic D. vulgaris cells and sessile cells on copper. [Display omitted] [ABSTRACT FROM AUTHOR]

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المؤلفون: Chen, Shiqiang¹ (AUTHOR) chenshiqiang@sdu.edu.cn, Hou, Ruizhi¹ (AUTHOR), Fu, Mengyu¹ (AUTHOR), Zhang, Xue¹ (AUTHOR), Dou, Wenwen¹ (AUTHOR), Li, Jiarun^1,2 (AUTHOR) lijiarun@qust.edu.cn, Liu, Guangzhou¹ (AUTHOR)

المصدر: Corrosion Science. Feb2024, Vol. 227, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *STEEL corrosion, *ARTIFICIAL seawater, *SOIL corrosion, *ELECTRONS, *CHARGE exchange, *SEAWATER, *CHARGE transfer

مستخلص: The effects of exogenous electron intermediaries, i.e., 9，10-anthraquinone-2-carboxylic acid (AQC), neutral red and thionine, on EH40 steel corrosion were investigated in seawater with Methanococcus maripaludis. Results showed that M. maripaludis can acquire electrons from EH40 steel through indirect electron transfer facilitated by these three exogenous electron intermediaries, thereby enhancing the charge transfer during corrosion process. This promotion effect on EH40 steel corrosion follows an order: AQC > neutral red > thionine, which correlates with their respective charge transfer capacities. The introduction of exogenous electron intermediaries enhances pitting corrosion of EH40 steel induced by M. maripaludis. • The corrosive capacity of M. maripaludis is enhanced due to exogenous electron intermediaries. • Corrosion promoting effects are AQC > neutral red > thionine in M. maripaludis medium. • A wide variety of electronic intermediaries can be utilized by M. maripaludis. • Charge transfer capacity of intermediaries determines corrosive capacity of M. maripaludis. [ABSTRACT FROM AUTHOR]

المؤلفون: Chen, Shiqiang^1,2,3, Zhang, Dun^1,3 zhangdun@qdio.ac.cn

المصدر: Corrosion Science. Mar2019, Vol. 148, p71-82. 12p.

مصطلحات موضوعية: *CARBON steel, *CORROSION & anti-corrosives, *SEAWATER, *BIOFILMS, *SOIL micromorphology

مستخلص: Highlights • Thalassospira sp. is isolated and identified as one of facultative iron-reducing bacteria. • The effects of Thalassospira sp. on corrosion behavior of Q235 carbon steel in air-saturated seawater is investigated. • The presence of Thalassospira sp. promotes corrosion of Q235 carbon steel. • The heterogeneous adhesion of Thalassospira sp. biofilm provides an advantage for pitting corrosion of Q235 carbon steel. Abstract Thalassospira sp. is an iron-reducing bacterium isolated from the marine environment. Effects of T. sp. on corrosion behaviors of Q235 carbon steel in air-saturated seawater were studied. Results of electrochemical measurements and weight loss indicated that the presence of T. sp. promotes Q235 carbon steel corrosion. Surface analyses results showed that heterogeneous adhesion is a typical character for T. sp. biofilm on surface of Q235 carbon steel, and pitting corrosion is induced. The corrosion mechanism model of Q235 carbon steel in air-saturated seawater containing T. sp. is proposed through surface micromorphology analyses, composition determination and current distribution. [ABSTRACT FROM AUTHOR]

المؤلفون: Chen, Shiqiang¹ (AUTHOR) chenshiqiang@sdu.edu.cn, Deng, Hao¹ (AUTHOR), Zhao, Yudi¹ (AUTHOR), Lu, Shihang¹ (AUTHOR), Zhao, Yao¹ (AUTHOR), Cheng, Xin¹ (AUTHOR), Liu, Guangzhou¹ (AUTHOR) liuguangzhou@sdu.edu.cn, Dou, Wenwen¹ (AUTHOR), Chen, Jvna² (AUTHOR)

المصدر: Bioelectrochemistry. Aug2021, Vol. 140, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *RENEWABLE energy sources, *STEEL, *STEEL corrosion, *SEAWATER, *PITTING corrosion, *ARTIFICIAL seawater

مستخلص: • Hydrogenotrophic M. maripaludis can survive by utilizing acetate as energy source. • EH40 steel corrosion is initially inhibited in M. maripaludis culture medium. • Prolonged exposure with the methanogen leads to an eventual corrosion propagation. • M. maripaludis biofilm unevenly distributes on steel surface. • Pitting corrosion of EH40 steel is promoted in M. maripaludis culture medium. The corrosion behavior of EH40 steel in seawater enriched with Methanococcus maripaludis was investigated through electrochemical methods and surface analysis techniques. The results revealed that the hydrogenotrophic M. maripaludis strain can utilize acetate as an alternative energy source. Corrosion of EH40 steel is initially inhibited, but prolonged exposure with the methanogen leads to an eventual corrosion propagation. During the early stage of immersion in M. maripaludis culture medium, the formation of a protective corrosion products film inhibits EH40 steel corrosion. The presence of M. maripaludis promotes both anodic and cathodic reactions of EH40 steel in the late stage of exposure. Surface analyses revealed that pitting corrosion is closely related to uneven distribution of M. maripaludis biofilm on EH40 steel surface. [ABSTRACT FROM AUTHOR]

المؤلفون: Cheng, Xin¹ (AUTHOR), Fu, Mengyu¹ (AUTHOR), Chu, Wangchao¹ (AUTHOR), Chen, Shiqiang¹ (AUTHOR) chenshiqiang@sdu.edu.cn, Liu, Guangzhou¹ (AUTHOR) liuguangzhou@sdu.edu.cn

المصدر: Surface & Coatings Technology. Mar2024, Vol. 480, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *FERRIC oxide, *SEAWATER, *FOOD packaging, *GALVANIZING, *STEEL

مستخلص: A nanostructured Fe 2 O 3 /CdZnS/ZnS composite film was constructed on EH40 steel using anodization, hydrothermal, and successive ionic layer absorption and reaction method. The film can inhibit the diffusion of dissolved oxygen to the substrate steel in aerobic seawater, and anodic dissolution of the substrate steel in D. vulgaris containing anaerobic seawater, respectively. The film can inactivate bacteria by producing active chlorine under light, which improves its anti-adhesion efficiency. The film prepared by 50 times of ZnS deposition reaches the highest anti-adhesion efficiency of 71.0 % and 63.3 % toward P. aeruginosa and D. vulgaris under dark, and 98.5 % and 96.0 % under light, respectively. [Display omitted] • A multilayered Fe 2 O 3 /CdZnS/ZnS composite film was constructed on EH40 steel surface. • Film keep integrity in seawater and P. aeruginosa or D. vulgaris containing seawater. • Film inhibit P. aeruginosa or D. vulgaris adhesion under dark and light irradiation. • Film generates active chlorine under light to inactivate bacteria on its surface. [ABSTRACT FROM AUTHOR]

المؤلفون: Cheng, Xin¹ (AUTHOR), Fu, Mengyu¹ (AUTHOR), Dou, Wenwen¹ (AUTHOR), Chen, Shiqiang¹ (AUTHOR) chenshiqiang@sdu.edu.cn, Liu, Guangzhou¹ (AUTHOR) liuguangzhou@sdu.edu.cn

المصدر: Construction & Building Materials. Dec2023, Vol. 408, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *PSEUDOMONAS aeruginosa, *SOIL corrosion, *EPOXY coatings, *METAL coating, *FOURIER transform infrared spectroscopy, *SEAWATER, *CATHODIC protection

مستخلص: [Display omitted] • P. aeruginosa can cause benzene ring removal of epoxy coating. • Cathodic protection facilitates P. aeruginosa biofilm formation on coating surface. • Epoxy coating degrades rapidly due to combined effect of CP and P. aeruginosa. • Presence of P. aeruginosa promotes Cl− migrating through coating causing corrosion. The combination of coatings and cathodic protection (CP) is one of the most commonly used methods for corrosion protection of metal materials. However, the protection life of this method is difficult to match the original design, which mechanism is still not well known. Previous work reports that coatings experience degradation mainly due to cathodic disbondment and microbial factors in marine environments. To further explore the possible reason for this question, we studied the degradation behavior of epoxy coatings in the co-existence of CP and Pseudomonas aeruginosa in seawater using Electrochemical impedance spectroscopy (EIS), Confocal laser scanning microscope (CLSM), Scanning electron microscope (SEM), 3D microscopy, Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analyzer (TGA), and Energy disperse spectrometer (EDS). The EIS results indicate that coating resistance drops bellows 106 Ω cm2 after 35 d of immersion under the effect of P. aeruginosa alone, but the degradation rate of coatings increases in the co-existence of CP and P. aeruginosa. The coating resistance drops bellows 106 Ω cm2 after 7 d of immersion in the P. aeruginosa containing seawater at − 1.05 V CSE. This may be due to P. aeruginosa can cause benzene ring removal from the epoxy coating, and the presence of CP promotes biofilm formation on the coating surface. The thickness of biofilm is about 33.3 μm at − 1.05 V CSE , which is about 1.5 times larger than at OCP, and the diameter of microscopic defects is about 9 times larger than in sterile seawater at the same CP potential. The presence of P. aeruginosa accelerate Cl− penetrating through the coating causing pitting corrosion of the substrate steel. This study revealed that the shorter protection life of organic coating can be attributed to the combined effect of CP and microorganisms in marine environments. The findings of this study can be referenced for better understanding of the coating failure mechanism in marine environments, and provide guidance for selecting appropriate organic coatings with anti-fouling and anti-corrosive properties. [ABSTRACT FROM AUTHOR]

المؤلفون: Cheng, Xin¹ (AUTHOR), Dou, Wenwen¹ (AUTHOR), Hou, Ruizhi¹ (AUTHOR), Chen, Shiqiang¹ (AUTHOR) chenshiqiang@sdu.edu.cn, Liu, Guangzhou¹ (AUTHOR) liuguangzhou@sdu.edu.cn

المصدر: International Biodeterioration & Biodegradation. Jul2023, Vol. 181, pN.PAG-N.PAG. 1p.

مصطلحات موضوعية: *GLASS coatings, *CATHODIC protection, *SULFATE-reducing bacteria, *OFFSHORE structures, *SEAWATER, *SOIL corrosion

مستخلص: Organic coatings are widely used in combination with cathodic protection (CP) to protect marine structures against corrosion. Coating failure is associated with CP and microbial factors in marine environments. However, detailed studies on coating failure due to the co-existence of CP and microorganisms are lacking. In this study, we investigated the failure behavior of epoxy glass flake coatings immersed in seawater containing sulfate-reducing bacteria (SRB) at different CP potentials. The results revealed that the coating remained intact under the effect of CP or SRB acting independently but failed under the combined action of SRB and CP, forming blisters. The presence of CP promotes biofilm formation on the coating surface. As the CP potential decreased from −0.85 V CSE to −1.05 V CSE , the thickness of the biofilm increased. The synergistic effect of CP and SRB enlarges microscopic defects on coating surface and cracks between resin and glass flakes, and promote sulfide generated by SRB penetrating through the coating, which accelerates corrosion of substrate steel leading to coating blister. At CP potentials of −0.85 V CSE , −0.95 V CSE , and −1.05 V CSE , coating blisters were observed after 30 d, 20 d, and 5 d of immersion, respectively, in an SRB medium. The results demonstrate the existence of a synergistic effect between CP and SRB that facilitates coating failure, which increases in speed as the CP potential becomes more negative. [Display omitted] • Coating fails faster as cathodic protection potential decreases in SRB media. • S2− ions migrate through coating accelerating corrosion under synergistic effect. • Cathodic protection promotes biofilm formation on epoxy glass flake coating. • Coating fails initially in SRB medium after 5 d of immersion under −1.05 V CSE. [ABSTRACT FROM AUTHOR]

المؤلفون: Wu, Jiajia¹, Zhang, Dun¹ zhangdun@qdio.ac.cn, Wang, Peng¹, Cheng, Yong¹, Sun, Shimei^1,2, Sun, Yan¹, Chen, Shiqiang¹

المصدر: Corrosion Science. Nov2016, Vol. 112, p552-562. 11p.

مصطلحات موضوعية: *CORROSION & anti-corrosives, *DESULFOVIBRIO, *SEAWATER, *CARBON steel, *ABIOTIC stress, *BIOFILMS

مستخلص: Corrosion behavior of Q235 carbon steel is investigated in sterilized air-saturated natural seawater inoculated with mono-, and di-cultures of Desulfovibrio sp. ( D . sp.) and Pseudoalteromonas sp. ( P . sp.). The electrochemical and weight loss results demonstrate that the corrosion rate increases in the order: P . sp. ˂ D . sp. + P . sp. ˂ D . sp. ≈ abiotic blank. Mechanisms for the corrosion inhibition of P . sp. and the difference in the function of D . sp. in D . sp. and D . sp. + P . sp. containing media are discussed on the analysis of surface morphology, biofilm development, environmental parameters, and bacterium number. [ABSTRACT FROM AUTHOR]