scholarly journals Corrosion Inhibition Mechanism and Efficiency Differentiation of Dihydroxybenzene Isomers Towards Aluminum Alloy 5754 in Alkaline Media

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3067 ◽  
Author(s):  
Ryl ◽  
Brodowski ◽  
Kowalski ◽  
Lipinska ◽  
Niedzialkowski ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Functional Groups ◽  
Alkaline Media ◽  
Aluminum Surface ◽  
Inhibition Mechanism ◽  
Detailed Knowledge ◽  
Nmr Studies ◽  
Bicarbonate Buffer ◽  
Dihydroxybenzene Isomers ◽  
Aluminum Alloy 5754

The selection of efficient corrosion inhibitors requires detailed knowledge regarding the interaction mechanism, which depends on the type and amount of functional groups within the inhibitor molecule. The position of functional groups between different isomers is often overlooked, but is no less important, since factors like steric hinderance may significantly affect the adsorption mechanism. In this study, we have presented how different dihydroxybenzene isomers interact with aluminum alloy 5754 surface, reducing its corrosion rate in bicarbonate buffer (pH = 11). We show that the highest inhibition efficiency among tested compounds belongs to catechol at 10 mM concentration, although the differences were moderate. Utilization of novel impedance approach to adsorption isotherm determination made it possible to confirm that while resorcinol chemisorbs on aluminum surface, catechol and quinol follows the ligand exchange model of adsorption. Unlike catechol and quinol, the protection mechanism of resorcinol is bound to interaction with insoluble aluminum corrosion products layer and was only found efficient at concentration of 100 mM (98.7%). The aforementioned studies were confirmed with Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy analyses. There is a significant increase in the corrosion resistance offered by catechol at 10 mM after 24 h exposure in electrolyte: from 63 to 98%, with only negligible changes in inhibitor efficiency observed for resorcinol at the same time. However, in the case of resorcinol a change in electrolyte color was observed. We have revealed that the differentiating factor is the keto-enol tautomerism. The Nuclear Magnetic Resonance (NMR) studies of resorcinol indicate the keto form in structure in presence of NaOH, while the chemical structure of catechol does not change significantly in alkaline environment.

scholarly journals Corrosion Inhibition Mechanism and Efficiency Differentiation of Dihydroxybenzene Isomers Towards Aluminium Alloy 5754 in Alkaline Media

2019 ◽  
Author(s):  
Jacek Ryl ◽  
Mateusz Brodowski ◽  
Marcin Kowalski ◽  
Wiktoria Lipinska ◽  
Pawel Niedzialkowski ◽  
...  
Keyword(s):  
Aluminium Alloy ◽  
Functional Groups ◽  
Photoelectron Spectroscopy ◽  
Alkaline Media ◽  
Inhibition Mechanism ◽  
Detailed Knowledge ◽  
Nmr Studies ◽  
Keto Form ◽  
Bicarbonate Buffer ◽  
Dihydroxybenzene Isomers

Selection of efficient corrosion inhibitors requires detailed knowledge regarding interaction mechanism, which depends on the type and amount of functional groups within the inhibitor molecule. Position of functional groups between different isomers is often overlooked but not less important since factors like steric hinderance may significantly affect the adsorption mechanism. In this study we have presented how different dihydroxybenzene isomers interact with aluminium alloy 5754 surface, reducing its corrosion rate in bicarbonate buffer (pH = 11). We have shown the highest inhibition efficiency among tested compounds belongs to catechol at 10 mM concentration, although differences were moderate. Utilization of novel impedance approach to adsorption isotherm determination allowed to confirm that while resorcinol chemisorbs on aluminium surface, catechol and quinol follows ligand exchange model of adsorption. Unlike catechol and quinol, the protection mechanism of resorcinol is bound to interaction with insoluble aluminium corrosion products layer and was only found efficient at concentration of 100 mM (98.7%). The aforementioned studies were confirmed with scanning electron microscopy and x-ray photoelectron spectroscopy analyses. There is a significant increase of the corrosion resistance offered by catechol at 10 mM after 24 h exposure in electrolyte: from 63 to 98%, with only negligible changes in inhibitor efficiency observed for resorcinol at the same time. However, in the case of resorcinol a change in electrolyte color was observed. We have revealed that the differentiating factor is the keto-enol tautomerism. The NMR studies of resorcinol indicate the keto form in structure in presence of NaOH, while the chemical structure of catechol does not change significantly in alkaline environment.

scholarly journals ESTUDIO DE LA RESISTENCIA A LA CORROSION DEL ALUMINIO 6063 ANODIZADO

2017 ◽  
Vol 22 (2) ◽  
pp. 17
Author(s):  
Karín Paucar Cuba ◽  
Hugo Rojas Flores ◽  
Abel Vergara Sotomayor
Keyword(s):  
Corrosion Resistance ◽  
Aluminum Alloy ◽  
Sulfuric Acid ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Surface ◽  
Equivalent Circuits ◽  
Acid Salt ◽  
Mass Losses ◽  
Palabras Clave

El estudio de la resistencia a la corrosión del anodizado de una aleación de aluminio (AA6063) en ácido sulfúrico a diferentes tiempos de anodizado: 30, 45 y 60 min. se realizó usando la espectroscopia de impedancia electroquímica (EIE) y el ensayo de niebla salina ácida. (ASTM B287). Los datos obtenidos por EIE y su correlación con los circuitos equivalentes más apropiados permitieron determinar los parámetros asociados a la capa porosa y a la capa barrera del óxido protector formado sobre la superficie del aluminio en estudio. La exposición de las muestras anodizadas durante 250h a una niebla salina ácida permitió observar variaciones en su masa. De los resultados obtenidos por EIE y las pérdidas de masa de las muestras anodizadas se estableció que la película de anodizado de 45 minutos mostró una mayor resistencia a la corrosión en comparación con la obtenida a 60 y 30 min., respectivamente. Palabras clave.- Aluminio, Anodizado, Impedancia electroquímica, Niebla salina ácida. ABSTRACTThe study of the corrosion resistance of anodized on aluminum alloy (AA6063) in sulfuric acid to different times: 30, 45 and 60 min. was performed using electrochemical impedance spectroscopy (EIS) and the acid salt spray test (ASTM B287). The EIS’data and its correlation with the most appropriate equivalent circuits allowed to determine the parameters associated with the porous layer and the oxide layer protective barrier formed on the aluminum surface under study. Exposure of the samples anodized for a 250h salt spray acid allowed to observe changes in their mass. From the results obtained by EIS and the mass losses of the anodized samples was established that the anodized film of 45 minutes showed higher corrosion resistance compared to that obtained at 60 and 30 min, respectively. Keywords.- Aluminum, Anodized, Electrochemical impedance, Acid salt spray.

scholarly journals Superhydrophobic Self-Assembled Silane Monolayers on Hierarchical 6082 Aluminum Alloy for Anti-Corrosion Applications

2020 ◽  
Vol 10 (8) ◽  
pp. 2656 ◽  
Author(s):  
Amani Khaskhoussi ◽  
Luigi Calabrese ◽  
Edoardo Proverbio
Keyword(s):  
Aluminum Alloy ◽  
Surface Energy ◽  
High Water ◽  
Dip Coating ◽  
Aluminum Surface ◽  
Sliding Angle ◽  
Water Contact ◽  
Electrochemical Tests ◽  
Self Assembled ◽  
6082 Aluminum Alloy

In this work, a two-stage methodology to design super-hydrophobic surfaces was proposed. The first step consists of creating a rough nano/micro-structure and the second step consists of reducing the surface energy using octadecyltrimethoxysilane. The surface roughening was realized by three different short-term pretreatments: (i) Boiling water, (ii) HNO3/HCl etching, or (iii) HF/HCl etching. Then, the surface energy was reduced by dip-coating in diluted solution of octadecyltrimethoxysilane to allow the formation of self-assembled silane monolayers on a 6082-T6 aluminum alloy surface. Super-hydrophobic aluminum surfaces were investigated by SEM-EDS, FTIR, profilometry, and contact and sliding angles measurements. The resulting surface morphologies by the three approaches were structured by a dual hierarchical nano/micro-roughness. The surface wettability varied with the applied roughening pretreatment. In particular, an extremely high water contact angle (around 180°) and low sliding angle (0°) were evidenced for the HF/HCl-etched silanized surface. The results of electrochemical tests demonstrate a remarkable enhancement of the aluminum alloy corrosion resistance through the proposed superhydrophobic surface modifications. Thus, the obtained results evidenced that the anti-wetting behavior of the aluminum surface can be optimized by coupling an appropriate roughening pretreatment with a self-assembled silane monolayer deposition (to reduce surface energy) for anticorrosion application.

scholarly journals Study on Crack Initiation and Propagation of New Corrosion Inhibitor during Stress Corrosion of Aluminum Alloy

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Juan Du ◽  
Zi-ming Wei ◽  
Xu-dong Yang ◽  
Qing-mao Liu ◽  
Hai-peng Song ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Crack Initiation ◽  
Corrosion Inhibitor ◽  
Electrochemical Impedance ◽  
Sodium Succinate ◽  
Sodium Dodecyl ◽  
Sodium Dodecyl Benzene Sulfonate ◽  
Inhibition Mechanism ◽  
Crack Initiation And Propagation ◽  
Initiation And Propagation

In this paper, a novel method combining electrochemical impedance spectroscopy (EIS) and phase shift was used to systematically study the effect of corrosion inhibitor (sodium succinate, sodium dodecyl benzene sulfonate, and new corrosion inhibitor, namely, bis [2-amino-3-(dodecyl dimethyl quaternary ammonium) propyl]-propylamine dichloro) on crack initiation and propagation of aluminum alloy during the slow strain rate tensile process. Using a variety of characterization methods to verify the feasibility of using the new method for in-situ prediction, Kramers–Kronig transformations have been used to validate the experimental data obtained with the EIS measurements. The corrosion inhibition mechanism of these three kinds of inhibitors in the SSRT process was analyzed.

Corrosion behavior of aluminum alloy 5754 in cement‐based matrix‐simulating nuclear waste disposal conditions

2020 ◽  
Vol 72 (1-2) ◽  
pp. 383-395
Author(s):  
Christophe Mendibide ◽  
Vincent Dusquesnes ◽  
Valérie Deydier ◽  
Xavier Bourbon ◽  
Didier Crusset
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Behavior ◽  
Nuclear Waste ◽  
Waste Disposal ◽  
Nuclear Waste Disposal ◽  
Aluminum Alloy 5754

Collagen structure: new tricks from a very old dog

2016 ◽  
Vol 473 (8) ◽  
pp. 1001-1025 ◽  
Author(s):  
Jordi Bella
Keyword(s):  
Molecular Conformation ◽  
Helical Structure ◽  
Molecular Engineering ◽  
Detailed Knowledge ◽  
Collagen Structure ◽  
Nmr Studies ◽  
Conformational Variability ◽  
Collagen Peptides ◽  
Triple Helical Domain ◽  
Model Peptides

The main features of the triple helical structure of collagen were deduced in the mid-1950s from fibre X-ray diffraction of tendons. Yet, the resulting models only could offer an average description of the molecular conformation. A critical advance came about 20 years later with the chemical synthesis of sufficiently long and homogeneous peptides with collagen-like sequences. The availability of these collagen model peptides resulted in a large number of biochemical, crystallographic and NMR studies that have revolutionized our understanding of collagen structure. High-resolution crystal structures from collagen model peptides have provided a wealth of data on collagen conformational variability, interaction with water, collagen stability or the effects of interruptions. Furthermore, a large increase in the number of structures of collagen model peptides in complex with domains from receptors or collagen-binding proteins has shed light on the mechanisms of collagen recognition. In recent years, collagen biochemistry has escaped the boundaries of natural collagen sequences. Detailed knowledge of collagen structure has opened the field for protein engineers who have used chemical biology approaches to produce hyperstable collagens with unnatural residues, rationally designed collagen heterotrimers, self-assembling collagen peptides, etc. This review summarizes our current understanding of the structure of the collagen triple helical domain (COL×3) and gives an overview of some of the new developments in collagen molecular engineering aiming to produce novel collagen-based materials with superior properties.

scholarly journals Polymeric Organo-Silane Coatings for Aluminum Alloy Corrosion Protection by Self-Assembled Metho

2012 ◽  
Vol 9 (1) ◽  
pp. 435-442 ◽  
Author(s):  
Yabin Wang ◽  
Yanni Li ◽  
Fang Wang
Keyword(s):  
Aluminum Alloy ◽  
Corrosion Protection ◽  
Electrochemical Techniques ◽  
Aluminum Surface ◽  
Corrosion Resistant ◽  
Hot Air ◽  
Self Assembling ◽  
Defective Layer ◽  
Self Assembled ◽  
Aluminum Alloy Surface

The protective performances of coating formed by organo-silane with a linear alkyl chain for promoting aluminum alloy corrosion protection were evaluated by electrochemical techniques. The coatings were self-assembled in the hydrolyzed hydroalcoholic bath ofn-octyltriethoxysilane (OS) and cured at hot air oven by different time. The coatings prepared by the less self-assembled number and shorter cured time, were always porous and scarcely protective. On the contrary, those built by the more self-assembled number and the longer cured time had higher coverage on aluminum surface and favorable corrosion resistant property. The best results were obtained whenn-octyltri-ethoxysilane (OS) was hydrolyzed 25 h, self-assembling of OS was conducted for five times and the multi-layers were cured at 120 for 1∼2 hours. In this case, the thicker, high cross-linked and more scarcely defective layer was formed on aluminum alloy surface.

Chemical Surface Treatment for Enhanced Bonding Strength between Polymer Coating and Aluminum Alloy

2010 ◽  
Vol 447-448 ◽  
pp. 720-724
Author(s):  
Linda Y.L. Wu ◽  
Y.Y. Feng ◽  
G.J. Qi
Keyword(s):  
Surface Roughness ◽  
Aluminum Alloy ◽  
Chemical Treatment ◽  
Bonding Strength ◽  
Surface Characteristics ◽  
Contact Angles ◽  
Polymer Materials ◽  
Bending Test ◽  
Aluminum Surface ◽  
Porous Structures

Polymer materials are sometimes molded to aluminum alloy to form integrated industrial parts for special applications, such as high strength, heavy duty applications. To ensure the bonding strength for long term applications, chemical treatment of aluminum surface is a quick and efficient method prior to polymer injection molding onto aluminum part. In this study, chemical etching and anodizing processes were studied to obtain suitable surface roughness and porous structures to enhance the penetration of polymer into the pores leading to interfacial anchoring and high bonding strength. Surface roughness, surface contact angles, and surface porous structures were investigated by surface Profilometer, contact angle tester, and scanning electron microscopy. Bending tests and cracking analyses were carried out to determine the bonding strength. Optimized chemical treatment recipe and process parameters were established. Preferred surface characteristics are defined. The failure mechanism of bending test was analysed and correlated to the bending fracture phenomina.

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