Thermodynamic stability of CoOOH and its coprecipitation with manganese

Hem, John David; Roberson, C. E.; Lind, Carol J.

doi:10.1016/0016-7037(85)90173-5

Cited by 51 publications

(21 citation statements)

References 8 publications

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“…Stage 1 is due to the preferential corrosion of Al, since intermetallic Al 9 Co 2 is nobler than Al [29]. Current limiting stage 2 is due to the formation of surface films on Al, as supported by the fact that the free energies of formation of aluminum oxides and their hydrates are much more negative than those of cobalt oxides and their hydrates, as shown in Table 5 [54][55][56]. The above postulation will further be justified in Sections 3.2.4-3.2.6.…”

Section: Microstructure and Composition Datamentioning

confidence: 99%

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Lekatou

Sfikas

Petsa

et al. 2016

Metals

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Hypereutectic Al-Co alloys of various Co contents (7-20 weight % (wt.%) Co) were prepared by vacuum arc melting, aiming at investigating the influence of the cobalt content on the microstructure and corrosion behavior. Quite uniform and directional microstructures were attained. The obtained microstructures depended on the Co content, ranging from fully eutectic growth (7 wt.% and 10 wt.% Co) to coarse primary Al 9 Co 2 predominance (20 wt.% Co). Co dissolution in Al far exceeded the negligible equilibrium solubility of Co in Al; however, it was hardly uniform. By increasing the cobalt content, the fraction and coarseness of Al 9 Co 2 , the content of Co dissolved in the Al matrix, and the hardness and porosity of the alloy increased. All alloys exhibited similar corrosion behavior in 3.5 wt.% NaCl with high resistance to localized corrosion. Al-7 wt.% Co showed slightly superior corrosion resistance than the other compositions in terms of relatively low corrosion rate, relatively low passivation current density and scarcity of stress corrosion cracking indications. All Al-Co compositions demonstrated substantially higher resistance to localized corrosion than commercially pure Al produced by casting, cold rolling and arc melting. A corrosion mechanism was formulated. Surface films were identified.

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Section: Microstructure and Composition Datamentioning

confidence: 99%

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Lekatou

Sfikas

Petsa

et al. 2016

Metals

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show abstract

“…Most of the Co in the soils is contained in or associated with Mn in mineral form. Indeed, there is a large literature on the adsorption of cobalt by MnO 2 : in soils and sediments (Means et al, 1978b;Alloway, 1990), in fresh waters (Hem et al, 1985), in lakes (Balistrieri et al, 1992) and in sea water (Knauer et al, 1982;Hem et al, 1985;Santschi, 1988;Shaw et al, 1990). Studies of adsorption of Co(II) on synthetic birnessite have been carried out too by Crowther et al (1983).…”

Section: Behaviour Of Trace Elementsmentioning

confidence: 99%

Mobility of major-, minor- and trace elements in solutions of a planosolic soil: Distribution and controlling factors

Pelfrêne

Gassama

Grimaud

2009

Applied Geochemistry

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“…7) These observations indicate that released Mn(II) ions are immobilized by co-precipitation with CoOOH. 17) In contrast, Co 2þ ions were less sorbed on the synthetic Mn oxides and no release of Mn ions were observed (Fig. 2).…”

Section: Resultsmentioning

confidence: 90%

Selective Sorption of Co<SUP>2+</SUP> over Ni<SUP>2+</SUP> Using Biogenic Manganese Oxides

2009

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Preferential sorption of Co 2þ ions over Ni 2þ ions was achieved using biogenic Mn oxides produced by the Mn-oxidizing fungus Paraconiothyrium sp. WL-2 strain with a maximum selectivity coefficient ( Co ) of 18. The selective sorption was based on different sorption mechanism for Co 2þ and Ni 2þ and unique properties of biogenic Mn oxides. The octahedral Co 2þ ions occupy vacancies of central metal sites and edge sites in the octahedral Mn oxide unit structures of biogenic Mn oxides, where they are immobilized by oxidation to CoOOH by Mn(III). In contrast, Ni 2þ ions are sorbed primarily on layer edges at circumneutral pHs without oxidation. Selective sorption of Co 2þ over Ni 2þ on the biogenic Mn oxides results from more vacant sites, higher Mn(III) contents, and larger specific surface areas compared to synthetic Mn oxides.

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Thermodynamic stability of CoOOH and its coprecipitation with manganese

Cited by 51 publications

References 8 publications

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Al-Co Alloys Prepared by Vacuum Arc Melting: Correlating Microstructure Evolution and Aqueous Corrosion Behavior with Co Content

Mobility of major-, minor- and trace elements in solutions of a planosolic soil: Distribution and controlling factors

Selective Sorption of Co<SUP>2+</SUP> over Ni<SUP>2+</SUP> Using Biogenic Manganese Oxides

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