Corrosion Science and Technology

Talbot, David E.J.; Talbot, James D.R.

doi:10.1201/b13606

Cited by 54 publications

(36 citation statements)

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“…Generally, the corrosion resistance of aluminum decreases once alloying elements are introduced. − Reports on the effects of silicon on aluminum corrosion vary in the conclusions. Silicon has been found to induce intergranular corrosion when segregated to the grain boundaries of aluminum due to silicon being cathodic to the Al-rich matrix, while other studies have found that the corrosion current density of silicon is too low to significantly affect aluminum corrosion due to silicon’s polarized nature in aluminum. ,,, When eGaIn is also at the grain boundaries of aluminum, we find that silicon enhances the aluminum–water reaction, though the factors leading to this enhancement may differ than expected from corrosion theory. With only 0.6 wt % silicon considered here, the effect of silicon on the chemical activity of aluminum would be negligible.…”

Section: Results and Discussioncontrasting

confidence: 52%

“…Without eGaIn, the effects of silicon on aluminum corrosion are unclear. Some studies have shown that silicon behaves cathodically and induces localized or intergranular corrosion, while other studies have shown that silicon does not have an electrochemical effect on aluminum corrosion. ,,, Here, we have observed a significant increase in extent of and rate of the oxidation–reduction reaction in Si-doped aluminum containing eGaIn.…”

Section: Results and Discussionmentioning

confidence: 41%

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Effects of Mg and Si Doping on Hydrogen Generation via Reduction of Aluminum Alloys in Water

Meroueh

Eagar

Hart

2020

ACS Appl. Energy Mater.

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Harnessing the oxidation−reduction reaction between aluminum and water is an attractive option for hydrogen generation and storage. Using liquid metals as a method of circumventing aluminum's native oxide layer has been gaining popularity, yet the underlying reaction mechanism and various effects on hydrogen generation remain elusive. This article reports the investigation of liquid-metal-activated aluminum that has been doped with commonly employed alloying elements. We observe that the eutectic Ga−In penetrates through subgrain boundaries in aluminum, providing experimental evidence that the eutectic permeates as a line dislocation front. We also demonstrate the opposing effects that magnesium and silicon alloying elements have on the hydrogen-generating properties of liquid-metal-activated commercial aluminum alloys. Compared to pure aluminum, the addition of 0.6 wt % silicon to aluminum gives rise to significantly higher reaction rates and hydrogen yields (+20%). The addition of 1 wt % magnesium to aluminum significantly lowers the rate and yield, especially following 72 h of eutectic Ga−In permeation (−30%). When both magnesium and silicon are present in aluminum such that intermetallic particles are formed like in the commercial alloy AA6061, the rate and extent of the aluminum−water reaction are highly dependent on permeation time. After 96 h of permeation, Al + Mg, Si produces the same amount of hydrogen as pure aluminum produces following only 48 h of permeation. These experimental observations do not agree well with historical studies based on pure corrosion of aluminum, indicating that the reaction mechanism involving eutectic Ga−In is more complex and hence requires additional investigations to understand. Using these discoveries, we can now better predict the reaction rate of the aluminum with water when considering Mg-doped and/or Si-doped scrap aluminum as a fuel source, giving rise to more applications in which aluminum can be harnessed as a hydrogen production and storage technology.

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Section: Results and Discussioncontrasting

confidence: 52%

Section: Results and Discussionmentioning

confidence: 41%

Effects of Mg and Si Doping on Hydrogen Generation via Reduction of Aluminum Alloys in Water

Meroueh

Eagar

Hart

2020

ACS Appl. Energy Mater.

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“…This effect was probably associated with the lower pH of the medium induced by the fungal activity. Since the Al phases are fully soluble at pH <4 (according to the Pourbaix diagram for Al), local acidification leads to complete Al phase dissolution. This effect is less important for Fe solubilization, since significant solubilization is only expected at pH <2 …”

Section: Resultsmentioning

confidence: 99%

A Fed-Batch Strategy Integrated with Mechanical Activation Improves the Solubilization of Phosphate Rock by Aspergillus niger

Klaic

Plotegher

Ribeiro

et al. 2018

ACS Sustainable Chem. Eng.

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Solubilization of phosphate rock (PR) by microorganisms is an environmentally sustainable alternative to chemical processing for production of phosphate fertilizers. The effectiveness of this PR biological solubilization process is driven by the microbial production of organic acids that chelate the cations (mainly calcium) bound to phosphate. However, the biological solubilization efficiency has been limited by the PR solids content of cultivation systems and is still low for practical applications. Here, we propose a fedbatch strategy coupled with mechanical activation to improve the biological solubilization of PR by Aspergillus niger. An initial systematic study of the effect of the particle size of Itafoś phosphate rock (IPR), a low reactivity phosphate mineral (P 2 O 5 , 20%), on the biological solubilization of phosphorus revealed that the particle size played a key role in IPR solubilization. Increases of available phosphate of up to 57% under submerged cultivation and 45% for solid-state culture were observed for rocks that had been milled for only 10 min. A fed-batch procedure was proposed in order to increase the solids content while maintaining the P-solubilization efficiency, resulting in a remarkable increase of 78% in P-solubilization, compared to the conventional process. This proposed strategy could potentially contribute to the future development of biotechnological processes for the large-scale industrial production of phosphate fertilizers that are environmentally sustainable.

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“…The most remarkable result was found for the St/RP/S°system, where the material presented the same characteristics as RP/S°in terms of local acidulation but the higher SO 4 2− production led to a harsher pH, causing Al solubilization. According to the Pourbaix diagram 40 for Al, aluminum phases (including oxides) are highly soluble at pH < 4, with subsequent reprecipitation as P-Al phases. This probably occurred in a diffusion zone (Scheme 1) where the pH was reduced to the average soil pH and Al phases could reprecipitate.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Smart Fertilization Based on Sulfur–Phosphate Composites: Synergy among Materials in a Structure with Multiple Fertilization Roles

Guimarães

Klaic

Giroto

et al. 2018

ACS Sustainable Chem. Eng.

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Sulfur is currently a bottleneck for agronomic productivity. Many products are based on the application of elemental sulfur (S°), but the ability of the soil to oxidize them is variable and dependent on the presence of oxidizing microorganisms. In this work, a composite was designed based on a matrix of S°prepared by low-temperature extrusion, reinforced by rock phosphate particles acting as P fertilizer, and with encapsulation of Aspergillus niger as an oxidizing microorganism. This structure was shown to be effective in significantly increasing S°oxidation while providing P by rock phosphate dissolution in an acid environment. X-ray absorption near-edge structure (XANES) spectra provided information about P fixation in the soil after dissolution, showing that the composite structure with A. niger modified the nutrient dynamics in the soil. This fully integrated material (a smart fertilizer) is an innovative strategy for eco-friendly agronomic practices, providing high nutrient delivery with minimal source preprocessing.

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Corrosion Science and Technology

Cited by 54 publications

References 0 publications

Effects of Mg and Si Doping on Hydrogen Generation via Reduction of Aluminum Alloys in Water

Effects of Mg and Si Doping on Hydrogen Generation via Reduction of Aluminum Alloys in Water

A Fed-Batch Strategy Integrated with Mechanical Activation Improves the Solubilization of Phosphate Rock by Aspergillus niger

Smart Fertilization Based on Sulfur–Phosphate Composites: Synergy among Materials in a Structure with Multiple Fertilization Roles

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