Статті в журналах: "Natural corrosion testing"

1

Wright, Ruishu F., Ping Lu, Jagannath Devkota, Fei Lu, Margaret Ziomek-Moroz, and Paul R. Ohodnicki. "Corrosion Sensors for Structural Health Monitoring of Oil and Natural Gas Infrastructure: A Review." Sensors 19, no. 18 (September 13, 2019): 3964. http://dx.doi.org/10.3390/s19183964.

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Corrosion has been a great concern in the oil and natural gas industry costing billions of dollars annually in the U.S. The ability to monitor corrosion online before structural integrity is compromised can have a significant impact on preventing catastrophic events resulting from corrosion. This article critically reviews conventional corrosion sensors and emerging sensor technologies in terms of sensing principles, sensor designs, advantages, and limitations. Conventional corrosion sensors encompass corrosion coupons, electrical resistance probes, electrochemical sensors, ultrasonic testing sensors, magnetic flux leakage sensors, electromagnetic sensors, and in-line inspection tools. Emerging sensor technologies highlight optical fiber sensors (point, quasi-distributed, distributed) and passive wireless sensors such as passive radio-frequency identification sensors and surface acoustic wave sensors. Emerging sensors show great potential in continuous real-time in-situ monitoring of oil and natural gas infrastructure. Distributed chemical sensing is emphasized based on recent studies as a promising method to detect early corrosion onset and monitor corrosive environments for corrosion mitigation management. Additionally, challenges are discussed including durability and stability in extreme and harsh conditions such as high temperature high pressure in subsurface wellbores.

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2

Machuca, Laura L., Stuart I. Bailey, and Rolf Gubner. "Crevice Corrosion Studies on Corrosion Resistant Alloys in Stagnant Natural Seawater." Advanced Materials Research 610-613 (December 2012): 276–79. http://dx.doi.org/10.4028/www.scientific.net/amr.610-613.276.

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Crevice corrosion (CC) was investigated for a number of selected corrosion resistant alloys in natural seawater containing microorganisms for up to 18 months under stagnant conditions. Experimental controls consisted of tests in natural seawater filtered in accordance with hydrostatic testing procedures. The corrosion potential of alloys was monitored throughout exposure and corrosion was evaluated by weight loss and 3D optical microscopy. CC was initiated on several alloys and corrosion rates in time indicated a positive effect of seawater filtration on the long-term performance of the alloys. Microbial adhesion, as indicated by fluorescence microscopy, occurred mainly outside the crevice and differed according to the nature of the substratum surface.

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3

Hamadache, M., M. Mouli, F. Dif, N. Bouhamou, and A. S. Benosman. "Non-Destructive Testing for the Evaluation of Pozzolanic Mortar Reinforced to Corrosion." Advanced Materials Research 1064 (December 2014): 42–48. http://dx.doi.org/10.4028/www.scientific.net/amr.1064.42.

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Our work aims to studying the addition of the natural pozzolan located in Beni Saf (Algeria) at non-destructive testing for the evaluation of pozzolan mortar reinforced to corrosion. We chose to study this natural addition because of its low cost and its pozzolanic reactivity. To do this, we have carried out tests on mortars made to Portland cement CEM I 42,5 N and substituted by weight based percentages of different natural pozzolan (10%, 20% and 30%). We have measured the corrosion potential and the corrosion speed of different deadlines. The results indicated that is it possible to highlight the beneficial effect of this addition. The analysis of achievements shows that the addition of the pozzolan in optimal quantities has the following advantages: protection of reinforcement against corrosion and increase the resistance against the sulfate attack (5% Na2SO4).

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4

Hao, Bao Hong, Ding Zeng, Quan Yong Deng, Xi Yang Song, and Tin Tin Zhou. "Concrete Reinforcement Corrosion Characteristics and Grading Evaluation under Natural Conditions." Advanced Materials Research 1030-1032 (September 2014): 744–49. http://dx.doi.org/10.4028/www.scientific.net/amr.1030-1032.744.

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Abstract: The paper, by using various electrochemical methods, conducts non-destructive quantitative testing towards currently-used bridges, analyzes reinforcement corrosion characteristics under natural environment, concludes the influencing rule of natural environment on reinforcement corrosion, and reveals differences accelerated simulation environment by contrasting with preliminary laboratory results. The real bridge measurement results show that: weight loss ratio of reinforcement under humid environment can reach a maximum of 33% and a minimum of 18%; while weight loss ratio of reinforcement under dry environment falls between 8%-15%. The actual measurement results also show that: box girder and guard bar coated with waterproof layer help to protect reinforcing bars inside the concrete and effectively reduce the corrosion rate inside reinforcing bars with weight loss ratio around 4-8%. It contrasts the precision of two testing methods and comes to a conclusion that testing precision of linear polarization method is higher than that of impulse current method.

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5

Lahodny-Šarc, O., B. Kulušić, Lj Krstulović, D. Sambrailo, and J. Ivić. "Stainless steel crevice corrosion testing in natural and synthetic seawater." Materials and Corrosion 56, no. 8 (August 2005): 561–65. http://dx.doi.org/10.1002/maco.200503865.

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6

Septiyani Arifin, Devi Eka, Destri Muliastri, Rudi Rudiana, and Fitri Nur Indah Sari. "Green Corrosion Inhibitors to Head Off the Corrosion Rate of ST 37 Steels." Current Journal: International Journal Applied Technology Research 2, no. 1 (May 21, 2021): 21–28. http://dx.doi.org/10.35313/ijatr.v2i1.40.

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The corrosions process is a natural process and cannot be hindered, but it can be protected by adding a green inhibitor. Green corrosion inhibitors are a new alternative solution for corrosion protection because they are low-cost, biodegradable, and eco-friendly inhibitors. This research was used papaya leaves dan guava leaves extract as organic inhibitor solution by Maceration Method. The concentration of these green inhibitors is 0 mL, 1 mL, 2.5 mL, 3 mL, and 3.5 mL. The type of testing method used in this research is FTIR, PDP, and weight loss. The results show that there is Tanin function groups in papaya leaves and guava leaves extract. The potentiodynamic polarization shows the value of corrosion rate without inhibitor is 0,418 mm/year. In contrast, the corrosion rate was decreased with improving the green inhibitor as many 3.5 mL. The corrosion rate was decreased until 0,00055 mm/year, and the value of efficiency is 99,868%.

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7

Qi, Gang, Xinhao Qin, Jun Xie, Pengju Han, and Bin He. "Electrochemical corrosion behaviour of four low-carbon steels in saline soil." RSC Advances 12, no. 32 (2022): 20929–45. http://dx.doi.org/10.1039/d2ra03200g.

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8

Zeng, Weiguo, Xiaofeng Dang, Shuhua Li, Hongmei Wang, Hao Wang, and Bo Wang. "Application of non-contact magnetic corresponding on the detection for natural gas pipeline." E3S Web of Conferences 185 (2020): 01090. http://dx.doi.org/10.1051/e3sconf/202018501090.

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This study examined natural gas pipeline by the non-contact magnetic corresponding. To confirm the reliability for the examination of natural gas pipelines by non-contact magnetic corresponding, three abnormal nodes were detected by the appearance inspection and ultrasonic testing. The results suggested that the grade of abnormal nodes by non-contact magnetic corresponding were not absolutely agree with that of the corrosion by ultrasonic testing. However, there was an obvious relevance between the comprehensive index of F by non-contact magnetic corresponding and the maximum degree of corrosion by ultrasonic testing. To sum up, the magnetic corresponding was an effective non-contact detection technology for the natural gas pipeline, while it was necessary to rationally grade the abnormal node according to the comprehensive index of F.

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9

Xuan, L. P., M. A. Anwar, T. Kurniawan, H. M. Ayu, R. Daud, and Y. P. Asmara. "Caffeine as A Natural Corrosion Inhibitor for Mild Steel in Nacl Solution." JOURNAL OF SCIENCE AND APPLIED ENGINEERING 2, no. 2 (November 28, 2019): 63. http://dx.doi.org/10.31328/jsae.v2i2.1186.

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Corrosion inhibitors are substances that added to the environment in small concentration and can effectively reduce the corrosion rate that of a metal surface. Natural inhibitors are one types of inhibitor being researched as it brings less environmental impact on the environment. This research was focused on the application of caffeine as inhibitor for corrosion of mild steel in seawater condition. The objective of this project was to develop the relationship between caffeine concentration on the corrosion of mild carbon steel in both static and moving solution contained 3.5-wt% NaCl. Three types of solution were prepared, which are NaCl without addition of caffeine, NaCl with 1-wt% of caffeine and NaCl with 2-wt% of caffeine. Corrosion testing was carried out by weight loss measurement. The microstructures of corroded mild steel specimens were observed under optical microscope. The experimental results indicated that by adding caffeine into the environment medium, weight loss of mild steel specimen was reduced. The corrosion rate of specimens was decreased when more caffeine was added to the environment. From optical microscopic observation, caffeine performed its inhibition effect likely by forming a protective layer which acts as barrier to prevent further corrosion of mild steel in NaCl solution.

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10

Bui, Xuan Ba, Kharachenko U. V., and Beleneva I. A. "COMPARATIVE BEHAVIOUR OF CORROSION FOR CARBON STEEL IN NHATRANG BAY (VIETNAM) AND VLADIVOSTOK (RUSSIA) SEA WATER." Science and Technology Development Journal 14, no. 1 (March 30, 2011): 65–77. http://dx.doi.org/10.32508/stdj.v14i1.1862.

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Comparative results of corrosion testing for carbon steel in natural conditions of Nhatrang Bay (East Sea, Vietnam) and Vladivostok (Russian Federation) sea water are presented. It is concluded, that corrosion of carbon mild steel in marine environment of Nhatrang Bay at normal seawater salinity is 1.5 to 2.5 times higher than that in Vladivostoc sea water conditions.

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11

Yanchun, Zheng, Miao Cunjian, Hong Lixiang, and Guo Weican. "An Experimental Study on Phased Array Ultrasonic Testing for Internal Inspection of Gas Storage Wells." Materials Evaluation 80, no. 8 (August 1, 2022): 40–45. http://dx.doi.org/10.32548/2022.me-04278.

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A reduction in wall thickness, caused by corrosion, of the inner and outer surfaces of underground compressed natural gas storage wells is one of the main causes of failure. Therefore, taking wall thickness measurements is an important task during periodic inspection. This study proposes a corrosion detection technique based on the well’s shape using cylindrical convex ultrasonic phased array and develops a cylindrical convex phased array probe with 512 elements. Using an example well of ∅177 × 10.36 mm, the influences of process parameters such as active aperture, focal length, gain, and gate threshold are studied. In addition, an experiment is conducted on a sample well with artificial defects for parameters optimization. Next, experimental tests are carried out on the well at the test platform according to the optimized parameters. The results show that the proposed technique is of high sensitivity and efficiency for the detection of corrosion defects and is able to detect pitting corrosion of more than ∅2 mm and line corrosion of 1 mm width.

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12

Wolfenden, A., and RM Kain. "Crevice Corrosion Testing in Natural Seawater: Significance and Use of Multiple Crevice Assemblies." Journal of Testing and Evaluation 18, no. 5 (1990): 309. http://dx.doi.org/10.1520/jte12492j.

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13

Pradityana, Atria, Subowo, Hari Subiyanto, Eddy Widiyono, and Dwi Winarto Gathot. "Application of Seeds from Psidium Guajava as Organic Inhibitor." Key Engineering Materials 867 (October 2020): 103–8. http://dx.doi.org/10.4028/www.scientific.net/kem.867.103.

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Corrosion is the process of natural changes in the nature of a material due to the influence or reaction with the surrounding environment. One way to control it is by adding inhibitors. In this study, seeds from guava (Psidium Guajava) were used as organic inhibitors. The test material used is API 5L grade B steel. For corrosive media, a solution of 1 M H2SO4 is used. In experiments used variations in the concentration of extracts 0, 2, 3, 4, 5 and 6 ml. The results of the experiments showed a decrease in the corrosion rate of API 5L grade B when there were additional inhibitors. This is supported by the experimental results of Potentiodynamic Polarization. The rate of corrosion without the presence of an inhibitor shows 75,018 mmpy whereas in the presence of 2,8845 mmpy inhibitors. Based on the calculation, the inhibition efficiency is 96.155%. This is also indicated by the results of the testing of weight loss that has been done. The efficiency shown is 90.130%.

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14

Cobo Ocejo, Ignacio, Maria Victoria Biezma Moraleda, and Paul Linhardt. "Corrosion Behavior of Heat-Treated Nickel-Aluminum Bronze and Manganese-Aluminum Bronze in Natural Waters." Metals 12, no. 3 (February 23, 2022): 380. http://dx.doi.org/10.3390/met12030380.

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Nickel Aluminum Bronze (NAB) and Manganese Aluminum Bronze (MAB) are high-alloyed bronzes that are increasingly employed in several industrial sectors, mainly related to hostile environments due to their excellent properties against corrosion, cavitation, erosion and improved mechanical properties in relation to other copper-based alloys. These materials are very sensitive against thermal treatments due to a multiphase microstructure in as-cast condition. To contribute to the knowledge of the behavior of both alloys, the effect of thermal treatments on the corrosion behavior of NAB (CuAl10Fe5Ni5) and MAB (CuMn12Al8Fe4Ni2) was studied. As-cast material was subjected to various combinations of quenching and quenching and tempering at 850 °C and 600 °C. Corrosion testing was carried out using simulated sea and fresh water. The microstructures of the as-cast and heat-treated samples were characterized by metallography using two chemical agents with FeCl3 and NH4OH solutions and examination by optical and scanning electron microscopy. The major effect of thermal treatments on corrosion was found in influencing the amount and distribution of β-phase, which is prone to selective corrosion in both electrolytes.

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15

Alawi, H., A. Ragab, and M. Shaban. "Corrosion Fatigue Crack Growth of Steels in Various Environments." Journal of Engineering Materials and Technology 111, no. 1 (January 1, 1989): 40–45. http://dx.doi.org/10.1115/1.3226431.

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Corrosion fatigue crack growth of three steels namely: AISI C1018, AISI 4340, and Stainless 17-7PH is studied in various environments. Testing medias include natural sea water, polluted sea water from an industrial site, drinking water produced from desalination process, and laboratory environments. Results obtained for the three steels are consistent in showing that polluted sea water is the most aggressive environment followed by low bicarbonate and alkalinity drinking water, then natural sea water. An attempt is made to explain this extraordinary aggressiveness of the polluted sea water and drinking water.

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16

Krymskaya, Renata S., Ekaterina I. Plaskeeva, and Svetlana E. Bogdanova. "Biological testing of aqueous-based metal preservation technologies." Butlerov Communications 60, no. 12 (December 31, 2019): 70–74. http://dx.doi.org/10.37952/roi-jbc-01/19-60-12-70.

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This paper deals with an essential issue of safe methods for temporary metal products protection against corrosion. Nowadays, there are a lot of corrosion inhibitors available; however, most of them are based on chemically hazardous derivatives of amines, nitrites, and chromates contained therein. The listed substances negatively affect both people and the environment. In Arctic weather conditions it is especially important to have reliable and safe anti-corrosion systems that can be applied in marine equipment preservation technologies. It is extremely undesirable to make any repairs and painting works under Arctic conditions, any restoration paintwork of metal items, as well as number of unpainted metal items to be protected must be minimized. The safest preservation methods are aqueous solutions; with such solutions, metal structures to be protected in Arctic conditions either do not need any preparatory preserving agent washing off, or washing off is ultimately simplified. This paper presents wide-spread inhibitors and inhibitors synthesized from safe natural fatty acids of vegetable oils. The article considers their characteristics and applicability. Also, the paper determines environmental hazard classes of aqueous preservation solutions by using biological testing objects. It allows us to assess a hazard level of the applied preservation method, regardless of how substances or combination thereof cause changes in vital functions of the testing objects. Based on the experiments conducted, the article discusses a possibility of using low-hazard preservation methods.

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17

Bouyanzer, A., B. Hammouti, L. Majidi, and B. Haloui. "Testing Natural Fenugreek as an Ecofriendly Inhibitor for Steel Corrosion in 1 M HCl." Portugaliae Electrochimica Acta 28, no. 3 (2010): 165–72. http://dx.doi.org/10.4152/pea.201003165.

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18

Jiao, Jinchao, Yong Lian, Zhao Liu, He Guo, Jin Zhang, Yan Su, Junpeng Teng, Yiming Jin, and Jinyan Chen. "Correlation between Laboratory-Accelerated Corrosion and Field Exposure Test for High-Strength Stainless Steels." Materials 15, no. 24 (December 19, 2022): 9075. http://dx.doi.org/10.3390/ma15249075.

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Equipment in a long-term marine atmosphere environment is prone to corrosion failure. Natural field exposure tests usually require a long time to obtain corrosion information. This study worked out a laboratory-accelerated corrosion test method that has a strong correlation with the natural environment test in Wanning, Hainan, and can be used as the basis for life assessment and the prediction of two high-strength stainless-steel materials. The mathematical model of corrosion weight loss of two high-strength stainless steels (3Cr13 and 00Cr12Ni10MoTi) was established by a field exposure test and a laboratory-accelerated corrosion test. Then, the correlation between the field exposure test and the laboratory-accelerated corrosion test was evaluated using qualitative and quantitative methods, and the acceleration ratio was calculated using the accelerated switching factor (ASF) method. The results show that: (1) The corrosion morphology of the two stainless steels after 15 days of laboratory-accelerated corrosion testing is similar to that obtained after two years of field exposure. (2) The value of gray correlation between the laboratory-accelerated corrosion test and the field exposure test is not less than 0.75. (3) The acceleration ratio of both stainless steels increases with the corrosion test time in the laboratory. The corrosion prediction models for the two stainless steels are T3Cr13 = 6.234 t1.634 and T00Cr12Ni10MoTi = 55.693 t1.322, respectively.

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Sun, Qi Lei, Ze Rui Liu, and Long Yang. "Application of Visual Basic (VB) Language on Stress Corrosion Cracking Test of Materials." Advanced Materials Research 941-944 (June 2014): 1372–75. http://dx.doi.org/10.4028/www.scientific.net/amr.941-944.1372.

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With Visual Basic (VB) language programming, on the basis of traditional SSRT testing, and by the superimposition of square wave load with certain frequency, the stress corrosion test of tensile fluctuating load can be realized. SCC sensitivity of specimen superimposed with square wave load is weaker and its fracture is flat. Results show that VB language programming can accurately and effectively simulate the fluctuating stress state of pipeline caused by pressure fluctuation of natural gas in the stress corrosion test of materials, and can better study the rule and mechanism of stress corrosion of materials, so as to find the economic and effective protection method.

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20

Li, Peng, Guo He Li, and Jian Liu. "A Simplified Method to Assess the Risk of Geotechnical Engineering under Hydro-Chemical Corrosion." Advanced Materials Research 243-249 (May 2011): 2952–57. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2952.

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Rock mass are subject to continuous changes induced by physical and chemical processes of natural and anthropic origin. Such changes affect their mechanical properties. To quantitatively evaluate the hydro-chemical corrosion, the theories of chemical thermodynamic and chemical kinetics are introduced. An index was proposed, which provides a criterion to judge whether the corrosion would be happened and indicated the reaction direction. Then based on theoretical and testing results, a hydro-chemical damage index was proposed. And a series of damage degrees of sandstone under different circumstances, which consider the variations of pH values, temperatures, ions species and ions concentrations, were calculated by chemical kinetics method. Based on the results, the sensitivity of influencing factors was discussed. According to the calculation and the theory of poromechanics or testing results, the mechanical properties of geotechnical materials under hydro-chemical corrosion process can be predicted, so can assess the risk of geotechnical engineering long-term stability.

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21

Chen, Mien-Chung, Ming-Che Wen, Yang-Chun Chiu, Tse-An Pan, Yu-Chih Tzeng, and Sheng-Long Lee. "Effect of Natural Aging on the Stress Corrosion Cracking Behavior of A201-T7 Aluminum Alloy." Materials 13, no. 24 (December 10, 2020): 5631. http://dx.doi.org/10.3390/ma13245631.

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The effect of natural aging on the stress corrosion cracking (SCC) of A201-T7 alloy was investigated by the slow strain rate testing (SSRT), transmission electron microscopy (TEM), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), conductivity, and polarization testing. The results indicated that natural aging could significantly improve the resistance of the alloys to SCC. The ductility loss rate of the unaged alloy was 28%, while the rates for the 24 h and 96 h aged alloys were both 5%. The conductivity of the as-quenched alloy was 30.54 (%IACS), and the conductivity of the 24 h and 96 h aged alloys were decreased to 28.85 and 28.65. After T7 tempering, the conductivity of the unaged, 24 h, and 96 h aged alloys were increased to 32.54 (%IACS), 32.52 and 32.45. Besides, the enthalpy change of the 24 h and 96 h aged alloys increased by 36% and 37% compared to the unaged alloy. The clustering of the solute atoms would evidently be enhanced with the increasing time of natural aging. Natural aging after quenching is essential to improve the alloy’s resistance to SCC. It might be due to the prevention of the formation of the precipitation free zone (PFZ) after T7 tempering.

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22

Zainal, F. F., N. S. Md Rahim, and R. Wardan. "The Effect of Current Densities in Zinc Electroplating Process on Mild Steel for Soil Water Environment Application." Solid State Phenomena 280 (August 2018): 226–30. http://dx.doi.org/10.4028/www.scientific.net/ssp.280.226.

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For more environmental friendly study, commonly undesired natural process which is corrosion will present. Thus, in this century there is a serious effort in ongoing analysis in order to prevent this phenomenon occurring. The challenge of corrosion in manufacturing and domestic sector is enormous. Thus, corrosion can be defined as the deterioration and destruction of a material because of reaction with the environment. Replacing a corroded pipeline can cost about $643,000 per kilometer. The application of the traffic sign or a road sign that embedded in soil usually can withstand for two to three years until it will corrode and then fracture. The main objectives of this study is to increase the protection on the surface of the materials towards corrosion and to improve the appearance of the product or serves as an effective undercoat for paints which can reduce the cost of using expensive material by using the other method; electroplating process. The samples were plated with zinc at 2, 4 and 6 A/dm2 for 20 minutes for every sample. Then, the samples were immersed in the artificial soil solution for 30 days, then the testing to measure the corrosion rate, phase analysis, morphological analysis and hardness test were conducted. From all the tests, sample with 6 A/dm2 got the best results with 5.2059 mpy and 80.6 HV hardness strength. It is because by increasing the current density, the thickness will then increase the zinc plating will not easily peel off and attack by corrosive agent.

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Duffy, Timothy S., Derek M. Hall, Margaret Ziomek-Moroz, and Serguei N. Lvov. "Technical Note: Monitoring X65 Steel Internal Corrosion in Humidified N2-Containing H2S Using Membrane-Based Electrochemical Sensors." Corrosion 77, no. 6 (March 15, 2021): 593–99. http://dx.doi.org/10.5006/3454.

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This paper will report on a new membrane-based electrochemical sensor that may provide an important utility in monitoring and characterizing internal corrosion of natural gas pipelines. Using this sensor, the corrosion rate of X65 steel exposed to H2S in humidified environments up to 60°C has been measured. Consistent with the authors’ earlier CO2 study, the membrane’s conductivity did not change when exposed to H2S-containing acidic gas. Introducing H2S consistently increased the measured corrosion rate between testing conditions, though corrosion rates were typically less than 2 μm/y. At 30°C, the corrosion rate doubled from 7.3 nm/y to 14 nm/y below a relative humidity of 30%, and it increased by an order of magnitude (0.19 μm/y to 1.9 μm/y) at 55% relative humidity, showing that the influence of H2S on corrosion increases dramatically with greater humidity. Trends with relative humidity match industry expectations: the corrosion rate is low (<0.25 μm/y) without the presence of a condensed aqueous phase, but it increases as the water content of the system increases. The membrane-based electrochemical sensor (MBES) was therefore able to capture relevant corrosion trends, even while the corrosion rates would not have presented a serious threat to any natural gas pipeline. As such, the MBES can be used to detect the onset of emerging corrosion threats before they occur. Field emission scanning electron microscopy and energy-dispersive x-ray spectroscopy confirmed that H2S reacted with the metal covered by the membrane phase, showing evidence of sulfur-rich sites on the X65 surface. In addition, finite element analysis (FEA) confirmed that electrochemical measurements and data analysis techniques could be successfully used for this membrane-based sensor, despite its unconventional cell geometry.

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Salnick, Alex O., and Werner Faubel. "Photoacoustic FT-IR Spectroscopy of Natural Copper Patina." Applied Spectroscopy 49, no. 10 (October 1995): 1516–24. http://dx.doi.org/10.1366/0003702953965461.

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Fourier transform infrared photoacoustic spectroscopy (FT-IR/PAS) has proved to be a useful tool for nondestructive testing of copper corrosion layer (patina) formed in the atmosphere. The samples cut from a piece of the roof of the Stockholm City Hall were examined without any additional pretreatment. The components of the patina—brochantite Cu4(OH)6SO4, antlerite Cu3(OH)4SO4, and basic cupric carbonate Cu2CO3(OH)6 · H2O—as well as some other minerals were identified. The photothermal beam deflection (PBD) method was used for independent photoacoustic characterization of the samples. The depth profiling capability of FT-IR/PAS was used to determine the degree of photoacoustic saturation of the spectral bands and to evaluate the depth distribution of the main patina components. The technique thus compares favorably with more common approaches of patina examination which are more expensive and require special sample preparation.

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Bautista, Asunción, Francisco Velasco, and Manuel Torres-Carrasco. "Influence of the Alkaline Reserve of Chloride-Contaminated Mortars on the 6-Year Corrosion Behavior of Corrugated UNS S32304 and S32001 Stainless Steels." Metals 9, no. 6 (June 14, 2019): 686. http://dx.doi.org/10.3390/met9060686.

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The durability of two lean corrugated duplex stainless steel (UNS S32304 and S32001) bars manufactured for concrete reinforcement was studied in four different corrosive conditions. These duplex stainless steels are more economical than the most traditional, well-known duplex grade steels (UNS S32205). The research was carried out in mortar samples for six years. In half of the samples, the alkaline reserve had been previously decreased, and their pH was slightly below 12, while in the other half, the pH close to the bars remained as-manufactured. Moreover, there were samples with modified and non-modified alkaline reserve where chlorides had been previously added to the mortar which were exposed to high relative humidity. In other samples—which were partially immersed in 3.5% NaCl—the chlorides entered through the mortar by natural diffusion. The electrochemical behavior of the reinforcements in these conditions was periodically monitored through corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) measurements during the whole testing period. The samples were anodically polarized at the end of the exposure. The results prove that the decrease in the alkaline reserve of the mortars can affect the corrosion behavior of the studied lean duplex in environments with high chloride concentrations. The duplex microstructure of the reinforcements makes it so that the corrosion proceeds by selective attack of the phases.

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Li, Ling Feng, Xiao Ming Liu, and Zhi Qiang Huang. "Study and Application for Corrosion-Resistant Material Selection of Tubing and Casing in Sour Gas Reservoirs under Coexistence of H₂S and CO₂." Advanced Materials Research 485 (February 2012): 429–32. http://dx.doi.org/10.4028/www.scientific.net/amr.485.429.

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For natural gas well with high content of CO2 and H2S, very serious corrosion in the gas well string is an important factor of gas production system life. In order to ensure the long-term development of gas wells, this paper mainly study the corrosion-resistant material selection of tubing and casing in sour gas reservoirs under coexistence of H2S and CO2 and proposes the optimization idea and technique of tubing and casing material selection. By taking Puguang gas field as an example, this paper optimizes the material selection of production casing for Puguang gas field. By testing, the optimal materials of gas well string in Puguang gas field have good performance of erosion resistance

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Yusa, Noritaka, Zhenmao Chen, Kenzo Miya, Tetsuya Uchimoto, and Toshiyuki Takagi. "Large-scale parallel computation for the reconstruction of natural stress corrosion cracks from eddy current testing signals." NDT & E International 36, no. 7 (October 2003): 449–59. http://dx.doi.org/10.1016/s0963-8695(03)00067-7.

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Marlianto, Eddy. "Efficiency of Ketapang (Terminalia catappa L.) Leaves Tannin Extract as Organic Inhibitor Against Corrosion Rate of Iron Metal in Seawater." Journal of Technomaterials Physics 2, no. 1 (February 28, 2020): 63–69. http://dx.doi.org/10.32734/jotp.v2i1.5268.

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The research is about effect of immersion time and mechanical properties on the rate of corrosion of ferrous metals by the addition of Ketapang (Terminalia catappa L.) leaf extract as an organic inhibitor in the seawater environment. In this study, ketapang leaf extract was used as a natural inhibitor to inhibit the rate of corrosion of ferrous metals. This inhibitor is used on iron metal plates which are immersed in corrosive media, namely sea water with variations in the composition of the inhibitors used at 0; 10% V; 20% V, and 40% V, with immersion time of 3 and 6 days. The characterizations tested included measurement of density, corrosion rate, inhibitor efficiency, and hardness testing using the Vickers method. From the measurement results, the density value decreases with the addition of the concentration of the inhibitor both on immersion 3 days and 6 days. The value of hardness increases with increasing composition of the inhibitor. The optimum hardness value is 165.03 N/m2 with immersion time of 6 days at an inhibitor concentration of 40% and a minimum hardness value of 145.603 N/m2 on immersion 6 days with no inhibitor. The smallest corrosion rate was obtained by samples with a composition of 40% inhibitor of 2.77 mpy with immersion time of 3 days and 1.33 mpy with immersion time of 6 days. And the efficiency value of Ketapang leaf extract inhibitors reached 47.01 % in the composition of 40% in the seawater environment with immersion time of 6 daysketapang leaves

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Buck, E. C., T. DiSanto, A. J. Bakel, and J. K. Bates. "Corrosion of a Plutonium-Bearing Titanate Ceramic." Microscopy and Microanalysis 3, S2 (August 1997): 747–48. http://dx.doi.org/10.1017/s143192760001062x.

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A titanate-based ceramic waste form, rich in phases structurally related to zirconolite (CaZrTi2O7), is being developed as a possible candidate for immobilizing excess plutonium from dismantled nuclear weapons. The waste form is made by cold pressing and sintering of CaO, TiO2, ZrO2, A12O3, BaO, and Gd and Pu oxides. A prototype Pu-loaded ceramic that is being tested contains Pu,Gd-zirconolite-(3T), Pu-bearing brannerite, Gd-zirconolite-(4M), zirconolite-(2M) (see Figure 1), rutile (TiO2), Gd-bearing perovskites, various aluminotitanate phases, and undissolved plutonium oxide. Evidence from laboratory testing and natural analogues of titanates suggests that these phases are extremely corrosion resistant. Zirconolite-rich ceramics have also been considered for the disposal of actinide-bearing waste streams, because zirconolite and related polytypes are able to incorporate at least 20 wt% of actinides. However, since each phase in the multiphase ceramic corrodes at a different rate, the release of any one component or the corrosion of the bulk waste form is difficult to predict

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Gohil, Piyush P., and A. A. Shaikh. "Cotton-Epoxy Composites: Development and Mechanical Characterization." Key Engineering Materials 471-472 (February 2011): 291–96. http://dx.doi.org/10.4028/www.scientific.net/kem.471-472.291.

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Composites are becoming essential part of today’s material because they offer advantages such as low weight, corrosion resistance, high fatigue strength; faster assembly etc. composites are generating curiosity and interest all over the worlds. The attempts can be found in literature for composite materials high strength fiber and also natural fiber like jute, flax and sisal natural fibers provides data but there is need of experimental data availability for unidirectional natural fiber composite with seldom natural fiber like cotton, palm leaf etc., it can provide a feasible range of alternative materials to suitable conventional material. It was decided to carry out the systematic experimental study for the effect of volume fraction of reinforcement on longitudinal strength as well as Modulus of Elasticity (MOE) using developed mould-punch set up and testing aids. The testing is carried out as per ASTM D3039/3039M-08. The comparative assessment of obtained experimental results with literature is also carried out, which forms an important constituent of present work. It is also observed through SEM images and theoretical investigations that interface/interphase plays and important role in natural fiber composite.

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Xavier, Joseph Raj. "Investigation on the effect of nano-ceria on the epoxy coatings for corrosion protection of mild steel in natural seawater." Anti-Corrosion Methods and Materials 65, no. 1 (January 2, 2018): 38–45. http://dx.doi.org/10.1108/acmm-04-2017-1784.

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Purpose This paper aims to investigate the effect of introducing nano-ceria (CeO2) particles to the epoxy coatings on mild steel in natural seawater. Design/methodology/approach The epoxy–ceria nanoparticles were coated with mild steel using a wire-wound draw-down bar method. The effects of ceria nanoparticles on the corrosion resistance of epoxy-coated samples were analyzed using scanning electrochemical microscopy (SECM) and electrochemical impedance spectroscopy (EIS). Findings Localized measurements such as oxygen consumption and iron dissolution were observed using SECM in natural seawater in the epoxy-coated sample. The increase in film resistance (Rf) and charge transfer resistance (Rct) values by the addition of nano-ceria particles in the epoxy coating was measured from EIS measurements after wet and dry cyclic corrosion test. Scanning electron microscope (SEM)/energy dispersive X-ray spectroscope (EDX) analysis showed that complex oxides of nano-ceria were enriched in corrosion products at a scratched area of the coated mild steel after corrosion testing. Focused ion beam-transmission electron microscope (FIB-TEM) analysis confirmed the presence of the nanoscale oxide layers of ceria in the rust of the steel. Research limitations/implications The tip current at −0.70 V for the epoxy–CeO2-coated sample decreased rapidly because of cathodic reduction of the dissolved oxygen. The increase in film resistance (Rf) and charge transfer resistance (Rct) values by the addition of nano-ceria particles in the epoxy coating were measured from EIS measurements after wet and dry cyclic corrosion test. Practical implications The presence of complex oxide layers of nano-ceria layers protects the coated steel from rusting. Social implications The use of this nano-ceria for corrosion protection is environment-friendly. Originality/value The results of this study indicated the significant effect of nano-ceria particles on the protective performance and corrosion resistance of the epoxy coating on mild steel. The dissolution of Fe2+ was lower in the epoxy–ceria nanoparticle-coated mild steel than that of the epoxy-coated mild steel resulting in a lower anodic current of steel. The increase in film resistance and the charge transfer resistance showed that the nano-ceria particles and the formation of complex oxides provide better barrier protection to the coating metal surfaces.

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Peng, Xiang, Kevin Siggers, and Zheng Liu. "Performance assessment of multi-MFL inspection using feature-based POD." Insight - Non-Destructive Testing and Condition Monitoring 63, no. 10 (October 1, 2021): 592–96. http://dx.doi.org/10.1784/insi.2021.63.10.592.

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Oil and gas pipelines, which transport large quantities of oil products and natural gas, are subject to pipeline failures caused by corrosion. Magnetic flux leakage (MFL) is one of the most popular non-destructive testing (NDT) techniques for the detection of pipeline corrosion. Since individual MFL is insensitive to the corrosion components that are parallel with its magnetic field, two types of MFL tools with perpendicular magnetic fields are usually employed in one inspection to detect all corrosion defects. This study applies probability of detection (POD) to quantitatively assess the detection capabilities of two individual MFL tools and their combination. Due to the characteristics of MFL inspection, this study proposes the construction of the POD model as a function of two geometric features, namely the volume and the orientation, which have a significant influence on the MFL signal response. Detection results from two MFL tools are integrated using logical OR operation to study the POD of their combination. With the proposed POD model, the minimum criteria that ensure a corrosion defect will be reliably detected by MFL tools are studied in this paper. The validity of the proposed POD model is justified on the data collected from an in-service pipeline.

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Vogt, Jean-Bernard, and Ingrid Proriol Serre. "A Review of the Surface Modifications for Corrosion Mitigation of Steels in Lead and LBE." Coatings 11, no. 1 (January 6, 2021): 53. http://dx.doi.org/10.3390/coatings11010053.

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The review paper starts with the applications of liquid metals and then concentrates on lead and lead–bismuth eutectic used in Gen IV nuclear reactors and accelerator-driven systems. Key points of degradation modes of austenitic stainless steels and ferritic-martensitic steels, candidates for the structural components, are briefly summarized. Corrosion and liquid metal embrittlement are critical issues that must be overcome. Next, the paper focuses on the strong efforts paid to the mitigation of corrosion and reviews the different solutions proposed for the protection of steels in lead and lead–bismuth eutectic. There exist promising solutions based on protection by deposition of protective coatings or protection by “natural” oxidation resulting from optimized chemical composition of the steels. However, the solutions have to be confirmed especially by longer-term experiments and by additional mechanical testing.

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Naik, Dayakar L., Hizb Ullah Sajid, Ravi Kiran, and Genda Chen. "Detection of Corrosion-Indicating Oxidation Product Colors in Steel Bridges under Varying Illuminations, Shadows, and Wetting Conditions." Metals 10, no. 11 (October 29, 2020): 1439. http://dx.doi.org/10.3390/met10111439.

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Early detection of corrosion in steel bridges is essential for strategizing the mitigation of further corrosion damage. Although various image-based approaches are available in the literature for corrosion detection, most of these approaches are tested on images acquired under uniform natural daylight illuminations i.e., inherent variations in the ambient lighting conditions are ignored. Owing to the fact that varying natural daylight illuminations, shadows, water wetting, and oil wetting are unavoidable in real-world scenarios, it is important to devise a robust technique for corrosion identification. In the current study, four different color spaces namely ‘RGB’, ‘rgb’, ‘HSV’ and ‘CIE La*b*’ along with a multi-layer perceptron (MLP) is configured and trained for detecting corrosion under above-mentioned real-world illumination scenarios. Training (5000 instances) and validation (2064 instances) datasets for this purpose are generated from the images of corroded steel plates acquired in the laboratory under varying illuminations and shadows, respectively. Each combination of color space and an MLP configuration is individually assessed and the best suitable combination that yields the highest ‘Recall’ value is determined. An MLP configuration with a single hidden layer consisting of 4 neurons (1st Hidden Layer (HL)(4N)) in conjunction with ‘rgb’ color space is found to yield the highest ‘Accuracy’ and ‘Recall’ (up to 91% and 82% respectively). The efficacy of the trained MLP to detect corrosion is then demonstrated on the test image database consisting of both lab-generated partially corroded steel plate images and field-generated images of a bridge located in Moorhead (Minnesota). Lab-generated images used for testing are acquired under varying illuminations, shadows, water wetting, and oil wetting conditions. Based on the validation studies, ‘rgb’ color space and an MLP configuration consisting of single hidden layer with 4 neurons (1st HL(4N)) trained on lab-generated corroded plate images identified corrosion in the steel bridge under ambient lighting conditions.

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Wilcke, Martin, Andrei Walther, Klaus Szielasko, and Sargon Youssef. "The MFL technique – Basic application for PT cable break detection in concrete structures." MATEC Web of Conferences 199 (2018): 06013. http://dx.doi.org/10.1051/matecconf/201819906013.

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From the beginning of building techniques creating pre-stressed and accordingly post-tensioned concrete structures until the late 1980ies manufacturers and construction companies dealt with pre-stressing steel material vulnerable to stress corrosion cracking. Almost every load-bearing structure requires regular inspection on a mandatory basis. Due to knowledge of pre-stressed structural reinforcement susceptible to stress corrosion cracking being used during construction or visible damage alongside the tendon area arises the demand for detailed investigation of cracks within the post-tensioned steel elements. Even though the pre-stressed steel elements of a structure are not especially at risk for stress corrosion cracking by its manufacturing process, the natural deterioration of the building fabric and manifold eventual defects and failure during structure erection encourage the requirement for an inspection of their structural integrity at least within the most important load-bearing areas. Therefore needed investigations can be carried out by application of the non-destructive magnetic flux leakage measurement technique for single bar elements and stranded wire tendons even inside cladding tubes. This testing method is subject to successful research work for more than 30 years now and has proven its validated functionality with impressive results on a big number of investigated structures including bridge elements, truss beams and container components.Starting with the basic physical measurement principle of magnetic flux leakage for dipole-formation in the area of fractures of the magnetized pre-stressed steel elements this document presents the practical application possibilities and development history of the testing method.With the consecutively presented further development of the BetoFlux-System we can provide a piece of testing equipment which combines the advantages of a pure physical measurement principle with the economical requirements for an on-site-application to investigate pre-stressed reinforcing steel elements at an early stage prior to structural collapse hazards.

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Joukoski, A., K. F. Portella, O. Baron, C. M. Garcia, G. R. Vergés, A. Sales, and J. F. de Paula. "The influence of cement type and admixture on life span of reinforced concrete utility poles subjected to the high salinity environment of Northeastern Brazil, studied by corrosion potential testing." Cerâmica 50, no. 313 (March 2004): 12–20. http://dx.doi.org/10.1590/s0366-69132004000100003.

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Reinforced concrete structures installed in coastal zones have constantly been threatened by environmental damaging elements. The chloride ion is known as one of the most aggressive of these elements, causing, among other damages, corrosion of the steel reinforcement and then degradation of the concrete matrix. The goal of this work was to determine the influence of cement type on the resistance and durability of reinforced concrete samples with 25 mm cover thickness, when submitted to aging in a 3.4% sodium chloride aqueous solution and in a high salinity marine environment. Reinforced concrete light poles were cast following the same batching procedures, and after the curing period, they were exposed to atmosphere in a corrosion station near Aracaju, Sergipe State, Northeastern Brazil's coast. Two concrete mixtures were made using CPII-F 32 (filler-modified Portland cement): a mix with no admixture and a mix with addition of 8% silica fume swapping fine aggregates. Another mixture was batched with CPV-ARI RS (high-early-strength Portland cement, with sulfur resistance). All the three mixtures were designed with cement content of about 350 kg/m³. The performance of the structures was evaluated from the results of physicochemical, mechanical and electrochemical testing, after over a year of natural aging. Corrosion potentials of the reinforced concrete samples and of the cast utility poles were measured in terms of the aging time at the natural environment and under chloride ion accelerated aging at laboratory. The half-cell potential measurements showed that the best results were obtained from the mixture containing CPII-F 32 cement and silica fume, followed by the concrete made with CPV-ARI RS cement. The mixture batched with CPII-F 32 cement without admixture presented the worst durability performance.

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Jamil, Ishrat, Humaira Bano, Vinod C. Malshe, Azhar Mahmood, Kamran Khan, and Nasir M. Ahmad. "Corrosion Resistance Synergistic Appraisal of Titanium-Impregnated Bisphenol A-Type Epoxy Duplex Coating System in Stimulated and Natural Marine Environments of Southeastern Coastal Area of China–Pakistan Economic Corridor." Advances in Polymer Technology 2021 (July 14, 2021): 1–11. http://dx.doi.org/10.1155/2021/9910969.

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This research endeavor is aimed at developing a protective coating for marine service conditions of the southeastern coastal area of the China–Pakistan Economic Corridor. Bisphenol A-type epoxy-based protective coatings were prepared by impregnating exotic titanium metal microparticles into two different proportions, i.e., 5% and 10% ( w / w ). Film hardness measurement by pencil test, adhesion measurement by the crosshatch-tape test, chemical and heat resistance test, gloss measurement, natural exposure, and salt spray testing have demonstrated that Ti-enriched coatings have performed better than the virgin epoxy coating. Moreover, scanning electron microscopy has depicted more surface degradation. Fourier transform infrared spectroscopy has indicated higher mass loss and chain scission in the virgin epoxy coating than the Ti-enriched coatings. In addition, these Ti microparticles have filled up the cavities/imperfections, reduced cracking, promoted crosslinking during the curing, and cordoned-off passage of corrodents and moisture, thus improving epoxy resin coating features. These results have widened the scope of Ti-embedded epoxy coatings against atmospheric corrosion for highly corrosive marine sites.

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Katkova, Svetlana S., and Vera I. Levashova. "SYNTHESIS AND STUDY OF INHIBITORY PROPERTIES OF QATERNARY AMMONIUM SALTS BASED ON AMINOETHYLETHANOLAMINE." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, no. 3 (April 13, 2017): 72. http://dx.doi.org/10.6060/tcct.2017603.5484.

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This article is devoted to the topical today biological corrosion problem of steel under the conditions of production, transportation and refining. The characteristics of corrosion caused by the vital activity of sulfate-reducing bacteria were analyzed. The article seeks to examine the effectiveness of new ammonium salts based on aminoethylethanolamine as reagents possessing inhibitory and antibacterial properties. The main content of the research is the analysis of the synthesis of new compounds based on ammonium aminoethylethanolamine and benzyl chloride. The optimal conditions of the synthesis were determined on the basis of the effect of temperature, reaction time, molar ratio of the final product output. The considerable attention was devoted to testing obtained new metal ammonium salts as acid corrosion inhibitors, including determining the corrosion rate and the degree of protection. The comparison of the results of the evaluation of the inhibitory properties of synthesized salts is presented using the rate indicator of corrosion "Monicor-2M" and gravimetric method. The results of the evaluation of bactericidal activity of the synthesized compounds were obtained with the determining the degree of suppression of sulfate-reducing bacteria SRB culture using isolated from natural sources and identified as Desulfovibrio desulfuricans. The results showed a high level of protective action of synthesized salts and their possible use in the oil industry.Forcitation:Katkova S.S., Levashova V.I. Synthesis and study of inhibitory properties of qaternary ammonium salts based on aminoethylethanolamine. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 3. P. 72-76.

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Mansour, E. M. E., A. M. Abdel-Gaber, B. A. Abd-El Nabey, N. Khalil, E. Khamis, A. Tadros, H. Aglan, and A. Ludwick. "Developing and Testing of a New Anticorrosive Coating Containing Algae as a Natural Inhibitor for Preventing Marine Corrosion of Steel." CORROSION 59, no. 3 (March 2003): 242–49. http://dx.doi.org/10.5006/1.3277557.

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Chen, Zhenmao, Ladislav Janousek, Noritaka Yusa, and Kenzo Miya. "A Nondestructive Strategy for the Distinction of Natural Fatigue and Stress Corrosion Cracks Based on Signals From Eddy Current Testing." Journal of Pressure Vessel Technology 129, no. 4 (September 7, 2006): 719–28. http://dx.doi.org/10.1115/1.2767365.

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In this paper, a novel nondestructive strategy is proposed for distinguishing differences between a stress corrosion crack (SCC) and a fatigue crack (FC) based on signals from eddy current testing (ECT). The strategy consists of measurement procedures with a special ECT probe and crack type judgment scheme based on an index parameter that is defined as the amplitude ratio of the measured signals. An ECT probe, which can induce eddy current flowing mainly in a selected direction, is proposed and applied to detect crack signals by scanning along the crack with different probe orientations. It is clear that the ratio of the amplitudes of signals detected for parallel and perpendicular probe orientations is sensitive to the microstructure of the crack, i.e., the parameter is much bigger for a fatigue crack than that of a SCC. Therefore, whether a crack is a SCC or a FC can be recognized nondestructively by comparing the index parameter with a threshold value that can be previously determined. In order to verify the validity of the proposed strategy, many artificial SCC and FC test pieces were fabricated and ECT inspections were performed to measure the corresponding crack signals. Numerical simulations were also conducted to investigate the physical principles of the new methodology. From both the numerical and experimental results, it is demonstrated that the strategy is very promising for the distinction of artificial SCC and FC; there is also good possibility that this method can be applied to natural cracks if the threshold value can be properly determined.

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Alembagheri, Mohammad, Maria Rashidi, and Mohammad Seyedkazemi. "Structural System Identification of Elevated Steel Water Tank Using Ambient Vibration Test and Calibration of Numerical Model." International Journal of Structural Stability and Dynamics 20, no. 10 (September 2020): 2071010. http://dx.doi.org/10.1142/s0219455420710108.

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This research aims to investigate the feasibility of using ambient vibration testing for system identification of an elevated water tank. To identify the natural dynamic properties, the experimental study is carried out on an elevated steel water tank located in Tehran. The tank is instrumented with a sensitive velocimeter sensor (microtremor), and the ambient velocity of the tank is recorded for 30[Formula: see text]min in three orthogonal axes. Employing the peak-picking method in the frequency domain, the fundamental frequency of the tank is determined as about 1.9[Formula: see text]Hz. Then, the numerical model of the tank is generated and calibrated based on the obtained data. In the primary modeling, the values of natural frequencies of the tank are in good agreement with the results of the ambient vibration data. This finding is judged to be reasonable considering no clear sign of corrosion in the steel material.

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Amir. "ANALISIS KERUSAKAN TUBE REFORMER DAN USAHA PENCEGAHANNYA." Jurnal Teknik Mesin Mechanical Xplore 1, no. 1 (January 14, 2021): 40–47. http://dx.doi.org/10.36805/jtmmx.v1i1.1283.

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dengan steam atau air. Reformer tersebut berfungsi untuk memecahkan gas hidrokarbon menjadi hidrogen. Proses reforming adalah proses reaksi CH4 + H20 CO + 3H2 yang memerlukan temperatur dan tekanan tinggi, reformer tersebut dioperasikan pada suhu 800-1000ºC dengan tekanan 2.1 kg/cm2. Dikarenakan pengoperasinya pada temperature yang tinggi maka ada gejala kerusakan pada sisi elbow tube reformer tersebut. Kerusakan pada tersebut disebabkan oleh beberapa factor seperti oksidasi, karburisasi (metal dusting),Nitridasi, korosi oleh halogen, korosi oleh logam cair dan korosi oleh deposit abu atau garam Carburization (metal dusting), Creep, Thermal shock, Prolong overheating, dan Short term overheating. Untuk mengetahui penyebab kerusakan pada bagian elbow tube reformer tersebut, maka dilakukan beberapa pengujian seperti pengujian komposisi kimia, pengujian metalografi, pengujian kekerasan, Berdasarkan analisa pengujian Laboratorium, maka elbow dari tube reformer tersebut mengalami oksidasi yang berarti korosi erosi karena mengalami penipisan pada elbow yang tidak merata dan terbentuknya partikel-partikel kecil yang mengakibatkan pengikisan material pada elbow reformer tube, untuk Melakukan langkah pencegahan, maka pada daerah elbow diberikan pelapisan permukaan dengan coating boron carbida, agar mendapatkan lapisan permukaan yang tahan terhadap aus, dan rendah gesekan dan juga tahan terhadap erosi, pelapisan permukaan pada sisi elbow dapat dilakukan dengan cara coating boron carbide setebal, 05 µm – 1,00 µm untuk mendapatkan kekerasan permukaan yang tinggi dan tahan aus yang tinggi dan korfisien gesekan yang rendah. Melakukan pemeliharaan rutin yang sesuai dengan persyaratan operasional pemeliharaan dan pengaturan kecepatan aliran gas operasional tetap terjaga. Kata kunci: Reformer, oksidasi, karburasi, nitridasi, korosi Reformer is a reactor which reaction of steam reforming take places. The reaction involves natural gas with steam or air. The reformer is used to break hydrocarbon gas into hydrogen. Reforming process is reaction process of CH4 + H2OCO + 3H2 which requires temperature and high pressure and operated at 800 - 1000ºC with a pressure of 2.1 kg/cm2. Due to its high temperature process, the damage symptoms exist onto elbow sides of reformer. Those damages was caused by several factors such as oxidation, metal dusting, nitridation, corrosion by molten metal’s and corrosions by ash deposits or salt carburization, creep, thermal shock, prolog overheating, and short-term overheating. To determine the cause of damage to the elbow tube reformer, some testing were conducted such as chemical composition testing, testing metallographic, hardness testing, testing then the elbow of the tube reformer that undergo oxidation, which means erosion corrosion due to the depletion of the elbow uneven and the formation of small particles that lead to the erosion of material at the elbow reformer tube, to Perform preventive measures, then in given the elbow area of surface coating with boron coating carbida, in order to get a surface layer which is resistant to wear and low friction and also resistant to erosion, surface coating on the side of the elbow can be done by way of boron carbide coating thickness of 05 μm - 1.00 μm for get a high surface hardness and high wear-resistant and low friction korfisien. Perform routine maintenance in accordance with the operational requirements of managing and maintaining the operational gas flow rate is maintained. Keywords: Reformer, oxidation, carburizing, nitriding, corrosion

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Yudin, Pavel, Sergei Petrov, Andrey Maximuk, and Zhanna Knyazeva. "Destruction mechanisms and methods of laboratory autoclave tests of internal coatings of oil pipes." E3S Web of Conferences 121 (2019): 01009. http://dx.doi.org/10.1051/e3sconf/201912101009.

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The main mechanisms of destruction of internal anticorrosive polymer coatings (IACPC) of the inner surface of tubing and fielding pipes are review in the article. They are divide into decompression peeling, substrate destruction under the corrosion of and natural aging of the polymeric basis. A critical analysis of the existing standards for the testing of internal anticorrosive coatings was made. The carrying out test on these documents does not allow obtaining the destructions identical to those found during the exploitation of pipelines. Investigations on the selection of optimal regimes of autoclave tests and the methodology for conduct research are describe. A comparison for the results of laboratory and experimental field tests of the coatings presented.

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Mann, V., C. Dechwayukul, W. Thongruang, S. Srewaradachpisal, P. Kaewpradit, W. Kaew Apichai, and H.-T. Bui. "Design and Fabrication a Lightweight Spring Made of Natural Rubber for a Motorcycle’s Shock Absorber." International Journal of Automotive and Mechanical Engineering 17, no. 1 (March 30, 2020): 7758–70. http://dx.doi.org/10.15282/ijame.17.1.2020.22.0577.

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This research aims to design and fabricate a spring made of natural rubber for a lightweight motorcycle’s shock absorber. This study is carried out in four main steps. First, a stiffness property of a steel coil spring and a damping property of a commercial shock absorber were tested using an Instron® material testing machine and a test rig. Second, six different types of rubber compounds (A-1, A-2, A-3, B-1, B-2, and B-3) were formulated and the best compound was selected to use for a rubber spring. Third, the rubber spring was designed and analyzed using the finite element method to investigate the best model. Finally, a prototype of the rubber spring was fabricated and tested. The steel coil spring was replaced by the rubber spring and tested for its damping property within a real shock absorber. The results of the prototype testing showed that the weight of the rubber spring was lower than the steel coil spring about 48%. The stiffness property of the rubber spring was higher than the steel coil spring around 43% and the damping property of the shock absorber using rubber spring was higher than the damping property of the shock absorber using steel coil spring about 6%. The rubber spring provided more advantages than the steel coil spring for its good corrosion resistance, lightweight, and ease of maintenance. However, the implementation of the rubber spring in the real motorcycle and its fatigue life should be studied in the next future.

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Bin, Shi Jie Bryan, Kai Soon Fong, Beng Wah Chua, and Manoj Gupta. "Development of Biocompatible Bulk MgZnCa Metallic Glass with Very High Corrosion Resistance in Simulated Body Fluid." Materials 15, no. 24 (December 16, 2022): 8989. http://dx.doi.org/10.3390/ma15248989.

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Magnesium-zinc-calcium (Mg-Zn-Ca) alloys as a biomaterial have attracted much attention recently, owing to their excellent biocompatibility, similar mechanical properties to natural bone, and biodegradable properties. Despite the numerous advantages of MgZnCa alloys, the rapid degradation of magnesium proved challenging as the implant in unable to retain its structural integrity for a sufficient duration of time. For metallic glasses, the capability to produce a bulk sample that is sufficiently large for useful applications have been far less successful owing to challenging processing parameters that are required for rapid cooling. In this study, Mg65Zn30Ca5 melt-spun ribbons were produced using melt-spinning followed by spark plasma sintering under high pressure (60 MPa) at different temperatures (130–170 °C) to provide an insight into the consolidation, mechanical, and corrosion behavior. Microstructural interfaces were characterized using scanning electron microscopy while the thermal stability of the amorphous phase was characterized using differential scanning calorimetry and X-ray diffraction. Here, pellets with 10 mm diameter and 10 mm height with a complete amorphous structure were achieved at a sintering temperature of 150 °C with densification as high at ~98%. Sintering at higher temperatures, while achieving higher densification, resulted in the presence of nano-crystallites. The mechanical properties were characterized using microhardness and compression tests. The hardness values of the sintered products were relatively higher to those containing crystallite phases while the ultimate compressive strength increased with increasing sintering temperature. Bio-corrosion properties were characterized via electrochemical testing with PBS as the electrolyte at 37 °C. The corrosion results suggest that the sintered samples have a significantly improved corrosion resistance as compared to as-cast samples. More notably, SPS150 (samples sintered at 150 °C) exhibited the best corrosion resistance (35× compared to as-cast in the context of corrosion current density), owing to its single-phase amorphous nature. This study clearly shows the potential of spark plasma sintering in consolidating amorphous ribbons to near-full density bulk pellets with high corrosion resistance for bio-applications.

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Ngo Xuan Hung, Tang Van Lam, Boris I. Bulgakov, Olga V. Aleksandrova, and Oksana A. Larsen. "EFINITION OF DEFORMATION OF FINE-GRAINED CONCRETE ON THE BASIS OF SULPHATE-RESISTANT PORTLAND CEMENT." Vestnik MGSU, no. 12 (December 2018): 1499–508. http://dx.doi.org/10.22227/1997-0935.2018.12.1499-1508.

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Introduction. The possibility of determining the relative deformations of fine-grained concretes based on sulfate-resistant cement was formulated by testing samples of gypsum-cement-sand mixture in distilled water in accordance with the requirements of the Vietnamese standard TCVN 6068:2004. Objective - to determine the deformations of fine-grained concrete because of sulfate-resistant Portland cement in accordance with the requirements of the TCVN 6068:2004 standard to assess its resistance to corrosion in an aggressive sulfate medium. Materials and methods. To obtain a gypsum-cement-sand mixture, a finely disintegrating binder was used, consisting of sulfate-resistant Portland cement of the type CEM I CC 42.5 N produced by the “Tam Diep” plant with the addition of natural gypsum produced by the company “Dinh Vu”. Quartz sand was used as fine aggregate. All raw materials used were native to Vietnam. Grinding fineness, normal cement density, setting time, the uniformity of the volume change and the activity of sulfate-resistant Portland cement were determined according to GOST 30744-2001; deformations of samples from gypsum-cement-sand mixtures - according to the Vietnamese standard TCVN 6068:2004. Results. Investigated the relative increase in the volume of samples of gypsum-cement-sand mixture based on sulfate-resistant Portland cement and natural gypsum as a result of their testing in distilled water according to the standard TCVN 6068:2004. Conclusions. Found that the average value of the relative deformation of the prism samples of concrete as a result of a 14-day test in distilled water was 0.037 %, which is within the acceptable value of 0.04 % in accordance with the requirements of the Vietnamese standard TCVN 6067:2004. Therefore, sulfate-resistant Portland cement type CEM I CC 42.5 N produced by the “Tam Diep” plant is a promising material as a binder for the preparation of corrosion-resistant concrete. The increase in the mean values of the relative deformations of the gypsum-cement-sand prism specimens after the 28-day and 60-day of testing, compared to the results of the 14-day test, can be explained by a slightly increased content of tricalcium aluminate in the studied cement.

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Kaur, Sarbjit, Niraj Bala, and Charu Khosla. "Investigations of thermal sprayed HAP and HAP-TiO2 composite coatings for biomedical applications." Anti-Corrosion Methods and Materials 66, no. 1 (January 7, 2019): 74–87. http://dx.doi.org/10.1108/acmm-03-2018-1917.

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Purpose The biomaterials are natural or synthetic materials used to improve quality of life either by replacing tissue/organ or assisting their function in medical field. The purpose of the study is to analyze the hydroxyapatite (HAP), HAP-TiO2 (25 percent) composite coatings deposited on 316 LSS by High Velocity Flame Spray (HVFS) technique. Design/methodology/approach The coatings exhibit almost uniform and dense microstructure with porosity (HAP = 0.153 and HAP-TiO2 composite = 0.138). Electrochemical corrosion testing was done on the uncoated and coated specimens in Ringer solution (SBF). As-sprayed coatings were characterized by XRD, SEM/EDS and cross-sectional X-ray mapping techniques before and after dipping in Ringer solution. Microhardness of composite coating (568.8 MPa) was found to be higher than HAP coating (353 MPa). Findings During investigations, it was observed that the corrosion resistance of steel was found to have increased after the deposition of HAP and HAP-TiO2 composite coatings. Thus, coatings serve as an effective diffusion barrier to prohibit the diffusion of ions from the SBF into the substrate. Composite coatings have been found to be more corrosion resistant as compared to HAP coating in the simulated body fluid. Research limitations/implications It has been concluded that corrosion resistance of HAP as well as composite coating is because of the desirable microstructural changes such as low porosity high microhardness and flat splat structures in coatings as compared to bare specimen. Practical implications This study is useful in the selection of biomedical implants. Social implications This study is useful in the field of biomaterials. Originality/value No reported literature on corrosion behavior of HAP+ 25%- TiO2 has been noted till now using flame spray technique. The main focus of the study is to investigate the HAP as well as composite coatings for biomedical applications.

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Gries, Matthew B., Kevin A. Michols, John S. Lawler, Elizabeth I. Wagner, Anthea Dennis, Koketso Kgatle, and Marita Pretorius. "Practical service life assessment and rehabilitation strategy development for hyperbolic shell natural draft cooling towers." MATEC Web of Conferences 364 (2022): 04022. http://dx.doi.org/10.1051/matecconf/202236404022.

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Years of service in industrial plant operating environments can cause varying types and degrees of concrete deterioration on reinforced concrete hyperbolic shell natural draft cooling towers. Exposure to plant operating cooling water can potentially result in concrete material erosion and corrosion of embedded reinforcing steel and associated concrete delamination and spalling over time. Such deterioration can affect the integrity of the structure to the degree that repair programs are required to reliably maintain the towers for their required service life. Condition assessment of natural draft cooling towers is challenging due to their massive size, hyperbolic geometry, and plant operational considerations (i.e. schedule, risk and cost). A case history is presented illustrating a rational and targeted investigation approach that included a combination of field condition survey, laboratory materials testing, consideration of operational constraints, probabilistic-based concrete deterioration service life modeling, and structural analysis. Existing degradation as well as predicted conditions from service life modeling informed structural analyses that were performed to identify risk-based limit states over time. The multi-faceted approach provided information critical to understand degradation mechanisms, characterize structural health, and develop prioritized repair strategies to obtain the desired service life extension.

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Almula, Thamir Aunal Deen Mohammed Sheet, Mohd Yazid Yahya, Amran Ayob, Iqbal Makhtar, and Amran Alias. "Mechanical Behavior of Composite Multilayered Basalt/E-Glass/Epoxy Pipe under Internal Pressure." Advanced Materials Research 1125 (October 2015): 227–34. http://dx.doi.org/10.4028/www.scientific.net/amr.1125.227.

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Pressurized composite pipes made of concentric fiber reinforced polymer layers have found much interest among researchers. These composite pipes possess mechanical and thermal properties that exceed those of their constituent materials. This development is motivated by the demand for corrosion resistant, lighter and high specific stiffness components. Natural fiber composite materials retain better flexural stiffness and are environmentally friendly. Unlike experimental testing, numerical investigations on the manufacture and performance of natural fiber reinforced pipes under internal pressure seem lacking. In this analysis, the mechanical behavior of multilayer composite pipes made of natural basalt and E-glass fibers under internal pressure were carried out numerically. The multilayered composite pipes were fabricated by employing filament winding technique with, basalt and E-glass fibers, with fiber orientation angles of ±45o, ±55o, ±65o, ±75o. The matrix epoxy resin was infused using vacuum infusion process (VIP). A longitudinal and hoop tensile test rig, designed and fabricated according to ASTM D2105 and D2299 respectively, was used to determine the hoop and longitudinal properties of the pipes. Numerical simulations were conducted to determine the stress and strain behaviors with the intention to find the effect of ply angle, basalt and glass properties and also to evaluate the performance of the new natural basalt fiber as an alternative to E-glass/Epoxy.

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Goldsworthy, Mathew William, James Sullivan, and Peter Barker. "The Effect of Ammonium Ions on the Corrosion Resistance of Zinc - Aluminium and Zinc - Aluminium - Magnesium Coated Steel." ECS Meeting Abstracts MA2022-01, no. 16 (July 7, 2022): 1019. http://dx.doi.org/10.1149/ma2022-01161019mtgabs.

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Galvanizing is the process of applying a protective zinc or zinc alloy coating to steel or iron which acts as a sacrificial anode to protect the underlying steel or iron. These coatings are mainly used in the automotive and construction industry where corrosive environments will be encountered. There has been a drive to improve the performance of galvanised coatings through alloy additions, initially Al (5 – 55 wt%) and more recently through the development of Zn - Al - Mg coatings. Here, Al and Mg are added as minority additions (typically 1 - 3 wt %) to improve corrosion resistance allowing thinner coatings to be used thus saving material, weight and cost. The assessment of the corrosion performance of such coatings is often evaluated through standardised tests. An industry standard test known as Prohesion or ASTM G85 Annex A5 is carried out on metallic coatings as it is thought to better represent long-term natural exposure than a regular salt spray test. The Prohesion test is a cyclic accelerated corrosion test using an electrolyte of 0.4% Ammonia sulphate and 0.05% sodium chloride (NaCl). This investigation aims to determine the effects on the corrosion performance of zinc-aluminium alloys and zinc-aluminium-magnesium alloys of varying compositions immersed in Prohesion solution. Previous work on this topic suggests that magnesium containing alloys were particularly susceptible to accelerated corrosion in Prohesion solution. Here, several zinc based alloys were immersed in Prohesion solution as well as a control 0.45% sodium chloride solution and subjected to electrochemical testing. The electrochemical techniques used to test said substrates are linear polarisation resistance (LPR), scanning vibrating electrode technique (SVET) and time-lapse optical microscopy (TLM) all for 24 hours. The alloys that underwent testing are shown in Table 1. Table 1: Table showing the composition of substrates used. Sample number Composition 1 Zn-<0.2wt%Al 2 Zn-5wt%Al 3 Zn-55wt%Al 4 Zn-1.2wt%Al-Zn1.2wt%Mg 5 Zn-3.5wt%Al-3wt%Mg 6 Zn-6wt%Al-3wt%Mg The results from the TLM showed differences in the corrosion mechanism that is dependent on the alloy composition and electrolyte. Generally, all substrates immersed in the control 0.45% NaCl showed localised corrosion with distinct anodes developing surrounded by a ring of corrosion product and white rust is observed on the surface of the substrate. The initial site of anodic attack in the microstructure was dependent on the alloy composition. However, when immersed in the Prohesion solution significant differences were observed dependent on the alloy composition. For Zn-Al-Mg coatings rapid attack of zinc-magnesium phases was observed especially in the eutectic regions followed by aggressive attack of the entire exposed surface of the alloy within 6 hours. Additionally, no corrosion product rings formed. For Zn-Al alloy coatings, the zinc phases were preferentially attacked with the aluminium containing phases appearing to be resistant to corrosion during the duration of the tests. No white rust was seen on the surface of the substrates and instead a dark surface/corrosion product film was observed. The corrosion rate from the LPR data measured at hourly intervals over 24 hours increases when substrates are immersed in Prohesion solution compared to NaCl, with the most noticeable increase seen when there are zinc-magnesium phases present within the alloy. The largest increase in corrosion rate mm per year (mmpy) was seen in sample 5 with it increasing from 0.15 mmpy after 24 hours in the control solution to 0.55 mmpy in the Prohesion solution after 24 hours. The same is observed with the SVET results showing that the ammonium ions are having a significant damaging effect on the Zn-Al-Mg metallic coatings. The proposed corrosion mechanism for Zn-Al-Mg alloy coatings in Prohesion solution is preferential dissolution of MgZn2 in eutectic phases due to reactivity of Mg producing Mg(OH)2 which is a highly basic hydroxide. Due to the basic nature of Mg(OH)2, Ammonium (NH4 +) cations react with Mg(OH)2 producing Mg2+ and Ammonia (NH3). Mg(OH)2+2NH4 +=Mg2++2NH3+2H2O Zn(OH)2 does not undergo this reaction to the same extent as it hydrolyses in water (producing H+) therefore is not basic enough to support much NH3 production. Neutral NH3 reacts with metallic Zn or Zn2+ compounds to produce highly soluble zinc (II) tetra-ammine complex cations. Therefore, the protective Zn and Mg compounds forming at the metal surface will dissolve and the surface will become activated. This is demonstrated by the lack of white rust shown from samples immersed in the Prohesion solution. Al phases are resistant to NH3 hence the better performance of Zn-Al coatings and the preferential attack of the Zn in the Zn-Al timelapse microscopy.

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