Phase Diagram Of Oxygen Research Articles

Phase diagram of oxygen up to 13 GPa and 500 K

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPhase diagram of oxygen up to 13 GPa and 500 KTakehiko Yagi, K. R. Hirsch, and Wilfried B. HolzapfelCite this: J. Phys. Chem. 1983, 87, 13, 2272–2273Publication Date (Print):June 1, 1983Publication History Published online1 May 2002Published inissue 1 June 1983https://doi.org/10.1021/j100236a004RIGHTS & PERMISSIONSArticle Views1102Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (271 KB) Get e-Alerts

Phase diagram of oxygen on Ni(100)

We have studied the coverage-temperature phase diagram of chemisorbed oxygen on Ni(100) with LEED and AES. We find that the oxygen p(2×2) structure undergoes a nearly reversible order- disorder phase transition for coverages between 0.15 and 0.30 monolayer ( T c ≈ 560 K for Φ = 0.25). For these coverages, it is also found that the chemisorbed oxygen begins dissolving into the bulk nickel as the overlayer disorders. A reversible order-disorder transition is not seen for the oxygen c(2×2) structure, but there is evidence that bulk dissolution here also occurs coincident with the overlayer disordering.

Phase diagram of oxygen on Ni(100)

We have studied the coverage-temperature phase diagram of chemisorbed oxygen on Ni(100) with LEED and AES. We find that the oxygen p(2 × 2) structure undergoes a nearly reversible order- disorder phase transition for coverages between 0.15 and 0.30 monolayer ( T c ≈ 560 K for θ = 0.25). For these coverages, it is also found that the chemisorbed oxygen begins dissolving into the bulk nickel as the overlayer disorders. A reversible order-disorder transition is not seen for the oxygen c(2 × 2) structure, but there is evidence that bulk dissolution here also occurs coincident with the overlayer disordering.

Phase diagram of oxygen on Ni(100)

We have studied the coverage-temperature phase diagram of chemisorbed oxygen on Ni(100) with LEED and AES. We find that the oxygen p(2×2) structure undergoes a nearly reversible order- disorder phase transition for coverages between 0.15 and 0.30 monolayer ( T c≈ 560 K for ϑ = 0.25). For these coverages, it is also found that the chemisorbed oxygen begins dissolving into the bulk nickel as the overlayer disorders. A reversible order-disorder transition is not seen for the oxygen c(2×2) structure, but there is evidence that bulk dissolution here also occurs coincident with the overlayer disordering.

Phase diagram of oxygen chemisorbed on nickel (111)

The complete phase diagram of oxygen atoms chemisorbed on Ni(111) has been determined. The two-dimensional system is realized for oxygen coverages of 0.5 monolayers and temperatures 500 K. At higher coverages and temperatures oxygen is incorporated into the bulk. The structure of the oxygen overlayer was determined by low-energy electron diffraction and the coverage was monitored by Auger electron spectroscopy. Oxygen forms two structures with long-range order on this surface: a $p(2\ifmmode\times\else\texttimes\fi{}2)$ phase in which the full coverage is 1/4 and a $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R{30}^{\ensuremath{\circ}}$ structure with full coverage of $\frac{1}{3}$. These phases are separated in coverage by a poorly ordered transition phase. The $p(2\ifmmode\times\else\texttimes\fi{}2)$ phase at full coverage ($\ensuremath{\theta}=0.25$) exhibits a continuous order-disorder transition at ${T}_{c}=440$ K. A tricritical point, corresponding to the intersection of boundaries of a disordered gas phase, a single-phase $p(2\ifmmode\times\else\texttimes\fi{}2)$ region, and a mixed-phase region of $p(2\ifmmode\times\else\texttimes\fi{}2)$ islands surrounded by gas, was found at $\ensuremath{\theta}=0.21$, ${T}_{t}=300$ K. The $(\sqrt{3}\ifmmode\times\else\texttimes\fi{}\sqrt{3})R{30}^{\ensuremath{\circ}}$ phase was observed at $\ensuremath{\theta}0.29$ and $T300$ K. This phase was characterized by a first-order discontinuous phase boundary. The work function increased smoothly with oxygen coverage.

Pseudobinary zircaloy-oxygen phase diagram

The zirconium-rich portion of the pseudobinary zircaloy-4/oxygen phase diagram was investigated by resistometric measurements and by metallographic analysis of equilibrated and quenched specimens. Accurate results for the phaseboundary locations were obtained from metallographic analysis of specimens in which oxidation and homogenization were limited to the α-phase region, and the specimens were rapidly quenched from equilibration temperatures in the β- and (αa + (β)-phase regions. The a- and (3-phase boundaries can be represented by the realtions In C α = −2.28 + 0.535 In ( T — 1083) and In Cβ = 5.02 − 8 220/ T ( for T > 1280 K or C β > 0.2), where C α and C β are the oxygen concentrations in weight percent and T is temperature in K.