Acid-Base Properties of Surface Oxide Films

McCafferty, E.

doi:10.1007/978-3-319-15648-4_1

Cited by 7 publications

(4 citation statements)

References 167 publications

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“…In fact, due to its polyelectrolyte properties, PAA's carboxylic groups become predominantly negatively charged at pH = 5 or higher 52 . Since the metallic surface is principally covered by OH2 + groups at high pHs 47,53 , the interactions between the polymer and the metal become stronger as pH increases.…”

Section: Sample Surface Tension (Mn/m)mentioning

confidence: 99%

Model Approach for Binder Selection in Binder Jetting

Yanez-Sanchez

Lennox

Therriault

et al. 2021

Ind. Eng. Chem. Res.

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Three binders, polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) are studied to elucidate the principal fundamental features giving rise to an excellent binder in a polymer-stainless steel particle array, used in the context of binder jetting. Using an out-of-printer screening approach, samples were compared based on compression tests, specifically the 0.2 % yield strength as a function of void volume fill factor, 𝜙, leading to a quasi-sigmoidal generalized curve for green body strength development. PVA demonstrated a strong tendency to form inter-particle bridges at low 𝜙 and the highest rise in strength, while PAA samples exhibited a lower tendency to form inter-particle bridges and a weak exponential rise in strength. This paper relates these behaviors to polymer strength, capillary properties and polymer-metal interactions and ultimately provides a rigorous selection process for binder efficacy.

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Section: Sample Surface Tension (Mn/m)mentioning

confidence: 99%

Model Approach for Binder Selection in Binder Jetting

Yanez-Sanchez

Lennox

Therriault

et al. 2021

Ind. Eng. Chem. Res.

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“…Moreover, it was intervened not only in interatomic but also in intermolecular interactions, with the final layer to have significantly increased resistance to corrosive factors, encountering both mass transfer and electrochemical attacking phenomena. The rust layer's outer surface is considered to have a chemical composition consisting of green rusts, FeO(OH), and Fe x O compounds, binding with hydrogen bonds and oxygen bridges; therefore, the point of zero charge of them fluctuates, especially for the α-crystals, between iron oxides and oxyhydroxides, from 7.5 to 9.38 at 22 • C. That confers to the layer to have a dynamic response to the increase of the pH locally, for a specific quantity i.e., of a basic compound and to function as an ion trap for the metallic surface [111,124,127].…”

Section: Time Of Exposure (H) Synergistic Parameter (S I )mentioning

confidence: 99%

Comparative Study on the Corrosion Inhibitive Effect of 2-Mecraptobenzothiazole and Na2HPO4 on Industrial Conveying API 5L X42 Pipeline Steel

et al. 2019

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Mild or low-carbon steel has an increasing utilization and is widely used for building construction, machinery parts, and pipelines, because it can be machined easily and has enhanced weldability as well as a low price. In any case, the corrosion resistance of mild steel under the conditions in industrial applications or in atmosphere is a thoughtful concern. This study inquires into the application of 2-mecraptobenzothiazole (MBT) and Na2HPO4 as corrosion inhibitors for the protection of API 5L X42 pipeline steel in 3.5 wt % NaCl as well as in water from the Athens city supply system. The electrochemical/morphological characterizations of the aforementioned mild steel proved that the corrosion protection mechanisms can be assigned to the protective layers created onto the metal surface because of the presence of the inhibitors, which prevent chloride’s penetration. The synergistic effect of the MBT and Na2HPO4 corrosion inhibition behavior, in a molar ratio of 1:1, revealed that the additives performed effectively with corrosion inhibition efficiency above 90%.

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“…However, the applicability of capillary models to solutions of long-chain polymeric molecules in binder jetting has not been previously investigated. Studies of polymer adhesion to metals have shown a range of bonding mechanisms, depending on the charge of the metal surface and the chemistry of the binder. , Aqueous solutions of polymer interact with oxides on the metal surface, notably through hydroxyl groups on the polymer and metal . In BJP, polymer–metal interfaces have been examined in the green body (after printing), but studies of the interaction of bulk binder solution are also needed to improve printing performance.…”

Section: Introductionmentioning

confidence: 99%

“…34,35 Aqueous solutions of polymer interact with oxides on the metal surface, notably through hydroxyl groups on the polymer and metal. 36 In BJP, polymer−metal interfaces have been examined in the green body (after printing), 37 but studies of the interaction of bulk binder solution are also needed to improve printing performance. A better understanding of the impact of polymer properties on binder−powder interaction is important for the future development of polymeric binders.…”

Section: ■ Introductionmentioning

confidence: 99%

Physicochemical Limitations of Capillary Models Applied to High-Concentration Polymer Solutions

et al. 2022

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Advances in binder jet printing (BJP) require the development of new binder–powder systems, for example, to increase compatibility with better performance metal alloys or to increase the strength of parts using stronger binders. The dynamics of binder absorption are principally understood through capillary models. However, validation of these models in BJP has focused on variation of powder properties. Using a design-of-experiments approach and an optical observation method to track absorption of droplets, this study tests the influence of fluid properties on absorption time against the predictions of capillary models. Properties specific to polymeric binders, such as molecular weight and entanglement state, are also considered. Capillary models are found to be generally accurate in predicting absorption time in dilute systems; however, these predictions are not accurate for highly concentrated binder solutions. The effect of polymer entanglement becomes prevalent as the solution concentration increases, which can also potentially occur as a result of increased evaporation due to powder bed heating. Specifically, concentrated solutions close to the onset of entanglement will absorb much more slowly than predicted. Future models of BJP systems must account for the possibility of polymer entanglement throughout the absorption process. Improved models will provide a more accurate understanding of the flow and solidification of the binder in the powder, allowing faster development of new binders for improved performance in printing.

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Acid-Base Properties of Surface Oxide Films

Cited by 7 publications

References 167 publications

Model Approach for Binder Selection in Binder Jetting

Model Approach for Binder Selection in Binder Jetting

Comparative Study on the Corrosion Inhibitive Effect of 2-Mecraptobenzothiazole and Na2HPO4 on Industrial Conveying API 5L X42 Pipeline Steel

Physicochemical Limitations of Capillary Models Applied to High-Concentration Polymer Solutions

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