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Wang, P. W.; Woo, J. C.; Avila, M.; Garcia, J.; Bronson, Arturo; Varma, S. K.

doi:10.1023/a:1021875700029

Cited by 6 publications

(1 citation statement)

References 21 publications

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“…Titanium is an active metal with various chemical valence states. It can form metastable or stable oxides at ambient temperature, which depends on the oxygen potential at the gas/solid interface and along the inter-diffusion zone [28]. Figure 7a,b shows the titanium XPS spectra for the initial powder and the powder after 720 h exposure, respectively.…”

Section: Characterization Of the Oxidation State Of Titaniummentioning

confidence: 99%

Oxidation Characteristics of Nickel-Based Superalloy Powders Exposed at Ambient Condition

Zhong

Jiao

Qiu

et al. 2022

Metals

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The existence of adsorbed oxygen and oxides on the surface of initial powders has serious effects on the microstructure and mechanical properties of the powder metallurgy alloys. However, the powder surface is inevitably oxidized immediately after the powder preparation. In this work, the oxidation characteristics for the argon atomized powders of a Ni-based superalloy containing Cr, Co, W, Mo, Ti, and Al after exposure at ambient condition for various time were investigated in detail. It is found that various gases can be absorbed on the powder surface, but most of them can be removed by low temperature (<151.5 °C) outgassing procedure. The thermodynamic calculation shows that the oxidation reaction occurs firstly with the alloying elements rather than Ni matrix, whether at room temperature or elevated temperature. The kinetic measurement indicates that the oxygen content on the powder surface approaches a saturation value after 24 h exposure and remains almost stable after 720 h. The oxygen content increases with the decrease of particle size after exposure. X-ray photoelectron spectroscopy characterized that, except the formed oxides, adsorbed oxygen also exists on the powder surface of the as-atomized initial fine powders with particle size <30 μm and the powders with size > 18.7 μm after exposure, which may be caused by the internal stress and surface energy of the initial atomized powder. All alloying elements except Ti can form stable oxides directly on the powder surface. For the element of Ti, the metastable TiO forms on the initial powder surface after preparation and it transforms into stable TiO2 or Ti2O3 during exposure. The results provide a deep understanding of absorbed gases and oxide on the surface of powders under treatment and possible desorption approach.

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Section: Characterization Of the Oxidation State Of Titaniummentioning

confidence: 99%

Oxidation Characteristics of Nickel-Based Superalloy Powders Exposed at Ambient Condition

Zhong

Jiao

Qiu

et al. 2022

Metals

View full text Add to dashboard Cite

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Manganese Compounds

Pisarczyk¹

2005

Kirk-Othmer Encyclopedia of Chemical Technology

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Manganese compounds are used commercially in the iron and steel industries, as a principal component of primary battery systems, and as oxidation reagents and catalysts. These compounds also find application in glassmaking and as fungicides, soft ferrite components, fertilizer, and pigments. Manganese exhibits oxidation states ranging from −III to VII in its compounds, and many of the known phases of manganese dioxide correspond to variations in degree of stoichiometry. Compounds for each manganese valency are discussed. Emphasis is placed on the manufacture, properties, and uses of a variety of natural and synthetic manganese dioxides and of potassium permanganate.

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