The inhibitive effect of a seaweed (SM) alcoholic extract on MS corrosion immersed in 1 M HCl, for 30 min, was evaluated by the WL method and PPD technique. The protective film was investigated by the Vickers hardness test. WL revealed that 500 ppm SM offered 84 % IE against MS corrosion in 1 M HCl. The inhibitor molecules adsorption onto the metal surface obeyed Langmuir’s adsorption isotherm. The R 2 value was very high (0.998). The PPD study showed that E corr slightly shifted to the anodic side. It was inferred that SM functions as a mixed type of corrosion inhibitor, since the shifts were relatively small. In SM presence, LPR value increased and I corr decreased. Due to the blanket effect (formation of a protective film on the metallic surface, which was found to be a monolayer, blocking anodic and cathodic sites), the electrons transfer from the metal into the solution was blocked. Vickers hardness of the inhibited MS surface was lower than that of the polished one, but higher than that of the corroded one. The outcome of the study may be used in the pickling industry, where HCl is used to remove the rust from the metal surface, simultaneously not attacking it.
{"title":"Mild Steel Corrosion Inhibition in 1 M HCl by an Alcoholic Extract of Sargassum Muticum","authors":"V. Jeslina, S. Kirubavathy, A. Al-Hashem, al et","doi":"10.4152/pea.2023410204","DOIUrl":"https://doi.org/10.4152/pea.2023410204","url":null,"abstract":"The inhibitive effect of a seaweed (SM) alcoholic extract on MS corrosion immersed in 1 M HCl, for 30 min, was evaluated by the WL method and PPD technique. The protective film was investigated by the Vickers hardness test. WL revealed that 500 ppm SM offered 84 % IE against MS corrosion in 1 M HCl. The inhibitor molecules adsorption onto the metal surface obeyed Langmuir’s adsorption isotherm. The R 2 value was very high (0.998). The PPD study showed that E corr slightly shifted to the anodic side. It was inferred that SM functions as a mixed type of corrosion inhibitor, since the shifts were relatively small. In SM presence, LPR value increased and I corr decreased. Due to the blanket effect (formation of a protective film on the metallic surface, which was found to be a monolayer, blocking anodic and cathodic sites), the electrons transfer from the metal into the solution was blocked. Vickers hardness of the inhibited MS surface was lower than that of the polished one, but higher than that of the corroded one. The outcome of the study may be used in the pickling industry, where HCl is used to remove the rust from the metal surface, simultaneously not attacking it.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921712","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work examined MLE as Zn corrosion inhibitor in a NaOH medium. MLE was subjected to qualitative and quantitative Pc analyses. Thermometric and gravimetric techniques were employed in the corrosion inhibition study. In the thermometric method, reaction numbers for Zn dissolution in blank and inhibited NaOH media were used to determine MLE IE(%). The gravimetric method was carried out using one factor at a time and RSM. CCD of DES was employed in RSM. The analyses of the experimental results revealed that MLE was predominantly made up of flavonoids, alkaloids and tannins (471.7, 458.3 and 115.0 mg/100 g, respectively). Zn by the extract increased with higher inhibitor C, but decreased with a rise in T. A quadratic model adequately described the relationship between IE(%), C, T and time factors. High IE(%) of 83.75% was obtained at an inhibitor C of 1.0 g/L, T of 303 K and IT of 5 h. Hence, MLE is a suitable inhibitor for Zn corrosion in a NaOH medium.
{"title":"Investigation of Mango (Mangnifera Indica) Extract as Zinc Corrosion Inhibitor in a Sodium Hydroxide Medium","authors":"M. Omotioma, O. Onukwuli, C. O. Nevo","doi":"10.4152/pea.2023410501","DOIUrl":"https://doi.org/10.4152/pea.2023410501","url":null,"abstract":"This work examined MLE as Zn corrosion inhibitor in a NaOH medium. MLE was subjected to qualitative and quantitative Pc analyses. Thermometric and gravimetric techniques were employed in the corrosion inhibition study. In the thermometric method, reaction numbers for Zn dissolution in blank and inhibited NaOH media were used to determine MLE IE(%). The gravimetric method was carried out using one factor at a time and RSM. CCD of DES was employed in RSM. The analyses of the experimental results revealed that MLE was predominantly made up of flavonoids, alkaloids and tannins (471.7, 458.3 and 115.0 mg/100 g, respectively). Zn by the extract increased with higher inhibitor C, but decreased with a rise in T. A quadratic model adequately described the relationship between IE(%), C, T and time factors. High IE(%) of 83.75% was obtained at an inhibitor C of 1.0 g/L, T of 303 K and IT of 5 h. Hence, MLE is a suitable inhibitor for Zn corrosion in a NaOH medium.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70922881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Scraped or end-of-life WC-Co bonded makes it an attractive resource. The conventional technologies to recover these metals entail energy-intensive pre-treatment steps, followed by their dissolution in a high volume of concentrated acids/alkali reagents. Recently, much attention has been given to the development of energy-efficient and environmentally friendly routes based on WC-Co direct electrochemical dissolution as anodes. However, the metals have a retarded dissolution, in NaOH alkali media, due to the formation of passive oxide layers, in the acidic electrolytes, and of hydroxides, on the anodic surface. The present study investigated WC and Co dissolution fundamentals in aqueous NH 3 , in order to develop a greener process, by the suitable addition of (NH 4 ) 2 CO 3 , (NH 4 ) 2 SO 4 and NH 4 Cl Preliminary PDP studies revealed the necessary concentration of NH 3 and additives, and their effect on the metals passivation tendency, for obtaining the best anodic dissolution parameters. The electrodissolution experiments in a specially designed cell achieved the maximum values, by adjusting those parameters. The highest dissolution of W and Co occurred under optimum conditions (10 V, 150 g/L NH 3 and 15% w/v NH 4 Cl). Co was deposited at the cathode, while H 8 N 2 O 4 W remained in the electrolyte and was recovered as H 2 WO 4 or YTO . Topographical analysis of the polarized surface by AFM has confirmed the pitting corrosion mechanism responsible for W and Co dissolution. A process flow chart for the newly developed single-step direct recycling methods of WC scraps has also been proposed. This process has produced pure saleable WO 3 powder and Co.
报废或报废的WC-Co粘合使其成为一种有吸引力的资源。回收这些金属的传统技术需要耗费大量能源的预处理步骤，然后将其溶解在大量的浓酸/碱试剂中。近年来，以WC-Co直接电化学溶解为阳极的节能环保路线的开发受到了广泛关注。然而，由于酸性电解质和阳极表面的氢氧化物形成了被动氧化层，金属在NaOH碱介质中溶解迟缓。本研究考察了WC和Co在nh3水溶液中溶解的基本原理，为了开发更环保的工艺，通过适当的(nh4) 2co3、(nh4) 2so4和nh4 Cl的加入，初步的PDP研究揭示了nh3和添加剂的浓度，以及它们对金属钝化倾向的影响，以获得最佳的阳极溶解参数。通过调整这些参数，在专门设计的电解池中进行电溶解实验，获得了最大值。在最佳条件(10 V, 150 g/L nh3和15% W / V nh4 Cl)下，W和Co的溶解率最高。Co沉积在阴极，而h8n2o4w留在电解液中，并被回收为h2wo4或YTO。用原子力显微镜对极化表面进行形貌分析，证实了W和Co溶解的点蚀机制。提出了新开发的单步直接回收WC废料的工艺流程图。该工艺生产出了纯可销售的三氧化二钒粉和钴。
{"title":"Recovery of Strategic Metals from Tungsten Carbide-Cobalt Bonded Waste by Electrochemical Processing","authors":"P. Katiyar, N. Randhawa","doi":"10.4152/pea.2023410202","DOIUrl":"https://doi.org/10.4152/pea.2023410202","url":null,"abstract":"Scraped or end-of-life WC-Co bonded makes it an attractive resource. The conventional technologies to recover these metals entail energy-intensive pre-treatment steps, followed by their dissolution in a high volume of concentrated acids/alkali reagents. Recently, much attention has been given to the development of energy-efficient and environmentally friendly routes based on WC-Co direct electrochemical dissolution as anodes. However, the metals have a retarded dissolution, in NaOH alkali media, due to the formation of passive oxide layers, in the acidic electrolytes, and of hydroxides, on the anodic surface. The present study investigated WC and Co dissolution fundamentals in aqueous NH 3 , in order to develop a greener process, by the suitable addition of (NH 4 ) 2 CO 3 , (NH 4 ) 2 SO 4 and NH 4 Cl Preliminary PDP studies revealed the necessary concentration of NH 3 and additives, and their effect on the metals passivation tendency, for obtaining the best anodic dissolution parameters. The electrodissolution experiments in a specially designed cell achieved the maximum values, by adjusting those parameters. The highest dissolution of W and Co occurred under optimum conditions (10 V, 150 g/L NH 3 and 15% w/v NH 4 Cl). Co was deposited at the cathode, while H 8 N 2 O 4 W remained in the electrolyte and was recovered as H 2 WO 4 or YTO . Topographical analysis of the polarized surface by AFM has confirmed the pitting corrosion mechanism responsible for W and Co dissolution. A process flow chart for the newly developed single-step direct recycling methods of WC scraps has also been proposed. This process has produced pure saleable WO 3 powder and Co.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921447","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Performance of Avocado Seeds as New Green Corrosion Inhibitor for 7075-T6 Al Alloy in a 3.5% NaCl Solution: Electrochemical, Thermodynamic, Surface and Theoretical Investigations","authors":"M. Radi, R. Melián, M. Galai, al et","doi":"10.4152/pea.2023410603","DOIUrl":"https://doi.org/10.4152/pea.2023410603","url":null,"abstract":"","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70923007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In continuation of our previously published work entitled Mechanical and Corrosion Behavior of Inconel 718 Nickel-Based Super Alloy Doped with Graphene Nanoplatelets , the present study investigated the tribological performance of modified IN 718 doped with GrNs. Friction and wear properties were analised using an advance universal tribometer, while surface mophologies were studied by SEM. The modified SA tribological properties validation was done in relative comparison to those of pure IN 718 . Mechanical properties with higher , younger modulus values, better morphologies, higher AWI, lower SWR and µ values were noted on the modified IN 718. Nonetheless, an increase in the load proved to affect the tribological oxide layer properties of both pure and modified IN 718. room temperature. The tests were run under dry lubrication conditions that are explained further ahead. A steel ball was used as the counterpart material against both standard and modified materials. The diameter size of the steel ball was 1.50 mm, and the acquisition rate was 3.14 Hz, with an equivalent stroke length of 6 mm. The measurements were intended to incorporate friction and wear properties from both pure and modified IN 718.
{"title":"Tribological Behavior of Inconel 718 Nickel-Based Super Alloy Doped with Graphene Nanoplatelets","authors":"K. Khoele, O. M. Ama, D. Disai, Al Et","doi":"10.4152/pea.2023410102","DOIUrl":"https://doi.org/10.4152/pea.2023410102","url":null,"abstract":"In continuation of our previously published work entitled Mechanical and Corrosion Behavior of Inconel 718 Nickel-Based Super Alloy Doped with Graphene Nanoplatelets , the present study investigated the tribological performance of modified IN 718 doped with GrNs. Friction and wear properties were analised using an advance universal tribometer, while surface mophologies were studied by SEM. The modified SA tribological properties validation was done in relative comparison to those of pure IN 718 . Mechanical properties with higher , younger modulus values, better morphologies, higher AWI, lower SWR and µ values were noted on the modified IN 718. Nonetheless, an increase in the load proved to affect the tribological oxide layer properties of both pure and modified IN 718. room temperature. The tests were run under dry lubrication conditions that are explained further ahead. A steel ball was used as the counterpart material against both standard and modified materials. The diameter size of the steel ball was 1.50 mm, and the acquisition rate was 3.14 Hz, with an equivalent stroke length of 6 mm. The measurements were intended to incorporate friction and wear properties from both pure and modified IN 718.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Characterization and Performance of TiO2 Nanoparticles Prepared by Microwave in Different Mixtures of Water and Ethylene Glycol for the Food Dye E131 VF Degradation","authors":"F. Kassir, M. Azoury, P. Damacet, al et","doi":"10.4152/pea.2023410305","DOIUrl":"https://doi.org/10.4152/pea.2023410305","url":null,"abstract":"","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70921947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
MS acceptability for nowadays structural construction is premised on its availability and low cost. However, due to MS poor corrosion resistance, most especially in acidic and alkaline environments, there have been increasing concerns about its use. The use of inhibitors, as proposed by different researchers, mitigates MS CR, thus reducing the economic losses experienced by all chief users of this alloy. In recent years, scientists have focused on green inhibitors obtained from plant, fruit and vegetable extracts, and essential oils. Besides being environmentally friendly, in terms of corrosion resistance, plant extracts are becoming increasingly important, due to their low cost and toxicity, and high availability. Additionally, they are rich in organic compounds with polar atoms, such as O, P, S and N, containing multiple bonds in their molecules, through which they can adsorb onto the metal surface, forming a protective film, by various adsorption isotherms. This paper provides a review on research works done so far on MS corrosion control by naturally occurring plant extracts as corrosion inhibitors, in both acidic and alkaline environments, where this alloy is mainly applied.
{"title":"The Efficacy of Plant Inhibitors as Used against Structural Mild Steel Corrosion: A Review","authors":"U. S. Nwigwe, C. Nwoye","doi":"10.4152/pea.2023410505","DOIUrl":"https://doi.org/10.4152/pea.2023410505","url":null,"abstract":"MS acceptability for nowadays structural construction is premised on its availability and low cost. However, due to MS poor corrosion resistance, most especially in acidic and alkaline environments, there have been increasing concerns about its use. The use of inhibitors, as proposed by different researchers, mitigates MS CR, thus reducing the economic losses experienced by all chief users of this alloy. In recent years, scientists have focused on green inhibitors obtained from plant, fruit and vegetable extracts, and essential oils. Besides being environmentally friendly, in terms of corrosion resistance, plant extracts are becoming increasingly important, due to their low cost and toxicity, and high availability. Additionally, they are rich in organic compounds with polar atoms, such as O, P, S and N, containing multiple bonds in their molecules, through which they can adsorb onto the metal surface, forming a protective film, by various adsorption isotherms. This paper provides a review on research works done so far on MS corrosion control by naturally occurring plant extracts as corrosion inhibitors, in both acidic and alkaline environments, where this alloy is mainly applied.","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70922599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Role of Nanomaterials in the Recent Development of Electrochemical Biosensors","authors":"S. Abdulhussein, F. F. Al-Kazazz, A. Rheima","doi":"10.4152/pea.2023410303","DOIUrl":"https://doi.org/10.4152/pea.2023410303","url":null,"abstract":"","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70922149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Protective Compositions Based on Modified Colza Oil Refining Products against Carbon Steel Atmospheric Corrosion","authors":"V. Vigdorovich, E. Tanygina, A. Tanygin, al et","doi":"10.4152/pea.2023410605","DOIUrl":"https://doi.org/10.4152/pea.2023410605","url":null,"abstract":"","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70923197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The present study has investigated electrolysis conditions, in which spatiotemporal structures onto the cathode surface could be observed for the first time, under strictly controlled settings, during Cu-Sb alloy ED. Self-organization phenomena, such as in depth self-assembled deposits structures, appeared when Sb content was higher than 70 wt% in the coatings. The layers and their structures different optical and morphologic areas were characterized
{"title":"Structure Formation and Multi-layering in an Electrodeposited Copper-Antimony Alloy","authors":"V. Kostov, T. Dobrovolska","doi":"10.4152/pea.2023410502","DOIUrl":"https://doi.org/10.4152/pea.2023410502","url":null,"abstract":"The present study has investigated electrolysis conditions, in which spatiotemporal structures onto the cathode surface could be observed for the first time, under strictly controlled settings, during Cu-Sb alloy ED. Self-organization phenomena, such as in depth self-assembled deposits structures, appeared when Sb content was higher than 70 wt% in the coatings. The layers and their structures different optical and morphologic areas were characterized","PeriodicalId":20334,"journal":{"name":"Portugaliae Electrochimica Acta","volume":"1 1","pages":""},"PeriodicalIF":1.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70922823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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