The formation of double-row oxide stripes during the initial oxidation of NiAl(100)

Qin, Hailang; Zhou, Guangwen

doi:10.1063/1.4819759

Cited by 18 publications

(25 citation statements)

References 20 publications

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“…LEED was used to verify the formation and structure of the oxide films formed from the in situ oxidation. The LEED patterns of the oxide films indicate a well-ordered (2 × 1, 1 × 2) structure (10,11), which is in accordance with the formation of θ-Al 2 O 3 films adopting the Bain epitaxy relationship between the fcc structure of the oxygen-sublattice and bcc structure of the NiAl substrate [i.e., (001) (7,(24)(25)(26).…”

Section: Methodsmentioning

confidence: 67%

“…Low-energy electron microscopy (LEEM), capable of imaging surfaces in video rate during gas exposure and at elevated temperatures, has been used to visualize the initial oxidation of NiAl(110), revealing the formation of aluminum oxide stripes that can elongate from one substrate terrace to the next by overgrowing surface steps (1)(2)(3). A similar stripe morphology of aluminum oxide has also been observed in NiAl(100) oxidation, although a detailed explanation of the mechanisms of the oxide growth is lacking (4)(5)(6)(7)(8)(9)(10)(11). Here, we use in situ LEEM observations of the initial-stage oxidation of NiAl(100) at elevated temperatures to quantitatively relate the Al 2 O 3 growth to the mass transfer process on the NiAl(100) surface.…”

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confidence: 99%

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Oxidation-driven surface dynamics on NiAl(100)

Qin

Chen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Atomic steps, a defect common to all crystal surfaces, can play an important role in many physical and chemical processes. However, attempts to predict surface dynamics under nonequilibrium conditions are usually frustrated by poor knowledge of the atomic processes of surface motion arising from mass transport from/to surface steps. Using low-energy electron microscopy that spatially and temporally resolves oxide film growth during the oxidation of NiAl(100) we demonstrate that surface steps are impermeable to oxide film growth. The advancement of the oxide occurs exclusively on the same terrace and requires the coordinated migration of surface steps. The resulting piling up of surface steps ahead of the oxide growth front progressively impedes the oxide growth. This process is reversed during oxide decomposition. The migration of the substrate steps is found to be a surface-step version of the well-known Hele-Shaw problem, governed by detachment (attachment) of Al atoms at step edges induced by the oxide growth (decomposition). By comparing with the oxidation of NiAl(110) that exhibits unimpeded oxide film growth over substrate steps we suggest that whenever steps are the source of atoms used for oxide growth they limit the oxidation process; when atoms are supplied from the bulk, the oxidation rate is not limited by the motion of surface steps.oxidation | NiAl | surface steps S urface growth processes are often treated with a simplifying assumption that the substrate is immobile. The rationale behind this general belief is that the role of the rigid substrate is to serve as a structural template, guiding the arrangement of impinging atoms. However, many surface growth processes involve reaction with the substrate (i.e., require sources or sinks of substrate atoms). In such cases, the role of the metallic substrate goes far beyond that of a passive support because of its active participation in the growth process. Such surface growth processes are typified by the oxidation of metals, during which the interaction between oxygen and a metallic substrate results in oxide growth by consuming the substrate atoms. Although extensive interest in understanding surface oxidation has existed for decades owing to its critical role in many technological processes including high-temperature corrosion, heterogeneous catalysis, and thin film processing, many issues are still unresolved, particularly those concerning the early stages of oxidation. A detailed understanding of the initial oxidation processes of surfaces has always been complicated by overwhelming inhomogeneities owing to high density of defects. Atomic steps are present on virtually any crystalline material in any environment and serve as natural sources and sinks of substrate atoms owing to the reduced coordination of atoms at step sites. In this work we address oxidation-induced surface dynamics as a result of mass transfer from and to steps. This is a critical issue because it influences both the mechanism and kinetics of the surface physical and chemical pro...

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Section: Methodsmentioning

confidence: 67%

mentioning

confidence: 99%

Oxidation-driven surface dynamics on NiAl(100)

Qin

Chen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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“…3 Unsymmetrical lattice misfit at the film-substrate interface and anisotropic strain has also been invoked to cause anisotropic island shapes. [4][5][6] Structural anisotropy is important in view of several applications, as it can endow the system with directional transport in wave-guides, sensors, and other nanodevice systems. 7,8 Here, we describe the formation of nanostripes with very high aspect ratios of a two-dimensional (2D) manganese oxide phase on a metal surface using a physical vapor deposition method.…”

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confidence: 99%

Kinetic asymmetry in the growth of two-dimensional Mn oxide nanostripes

et al. 2013

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Nanostripes with very high (>20) aspect ratios of a two-dimensional manganese oxide phase are grown on the Ag(100) surface using a physical vapor deposition method and thoroughly characterized via low-energy electron diffraction and scanning tunneling microscopy. Despite the square pattern of the substrate, symmetry breaking is produced by the structural anisotropy of the kinetically stabilized, metastable Mn surface oxide phase. As rationalized by a first-principles analysis, the resulting asymmetry in edge diffusion and attachment energies and the difference in adsorption energetics between Mn and Ag adatoms leads to the kinetic formation of such strikingly anisotropic structural domains: they feature nanoscale width (≈5-20 nm), mesoscopic length (up to ≈1 μ), very low defect density, and grow along the high-symmetry directions of the Ag(100) substrate.

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“…Even for a crystalline Al 2 O 3 , thin oxide stripes with the thickness as thin as ∼1 Å were observed from the oxidation of NiAl(100). 22 We also point out that this manner of the increase in the limiting thickness of the oxide film is different from the oxidation of an Al(111) surface by molecular oxygen or water vapor, for which the limiting thickness of the oxide film remains essentially constant at the pressure of ∼1 Torr for molecular oxygen 23,24 or 1 × 10 −2 Torr for water vapor, 21 irrespective of prolonged oxygen or water vapor exposure and further increase in oxygen or vapor pressure. Although the oxidation of the NiAl(100) surface by water vapor also shows stepwise growth of the limiting thickness of the passivating film with the stepwise increase in water vapor pressure, we find here that the limiting thickness increases in a stepwise manner only until a water vapor pressure of p(H 2 O) = 1 × 10 −2 Torr is reached.…”

Section: Resultsmentioning

confidence: 76%

X-Ray Photoelectron Spectroscopy Study of Silane Coupling Agents/Basalt Fiber Interface

Shen

Zhang

Shao

2011

AMR

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In this paper, two types of fiber surface treatment methods, namely heat treatment and chemical coupling, were used to improve the basalt fiber surface properties. The basalt fiber surface was heated under 250Celsius degree for 30minites, and then was treated by silane coupling agent ethanol solution with different concentrations. X-ray photoelectron spectroscopy (XPS) was utilized to study the surface chemical compositions of basalt fiber after treatments. The XPS analysis indicated that chemical bonds between basalt fiber and KH-550 have occurred, and silanols were adsorbed to the surface of basalt fibers by an ether linkage between the silanols and the hydroxyl groups of the fibers. When the concentration of KH-550 is 0.8wt%, the optimal bonding condition is formed between basalt fiber and silane coupling agent.

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The formation of double-row oxide stripes during the initial oxidation of NiAl(100)

Cited by 18 publications

References 20 publications

Oxidation-driven surface dynamics on NiAl(100)

Oxidation-driven surface dynamics on NiAl(100)

Kinetic asymmetry in the growth of two-dimensional Mn oxide nanostripes

X-Ray Photoelectron Spectroscopy Study of Silane Coupling Agents/Basalt Fiber Interface

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