Journal ArticleDOI
A quantitative demonstration of the grain boundary diffusion mechanism for the oxidation of metals
TLDR
In this article, the authors report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500-800°C.Abstract:
Below 1000°C the oxidation of nickel cannot be controlled by the diffusion of ions through the bulk crystal lattice of the pure oxide, because the measured oxidation rates are several orders of magnitude faster than would be predicted on this basis. Short-circuit diffusion through oxide grain boundaries or dislocations has usually been held responsible, but there has hitherto been no proper quantitative confirmation of this mechanism. We report measurements of the oxide scale thickness and oxide grain size as a function of time during the oxidation of high-purity nickel in the temperature range 500–800°C. All the oxidation experiments were carried out in pure oxygen at a pressure of one atmosphere. The measured parabolic oxidation rate constants have been compared with those calculated from grain boundary diffusion data obtained in our previous work, using a grain boundary diffusion model for the oxidation process. The quantitative agreement between measured and calculated oxidation rates shows c...read more
Citations
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Hardness of T-carbon: Density functional theory calculations
TL;DR: In this article, Sheng et al. showed that T-carbon is not a superhard material, since its Vickers hardness does not exceed 10 GPa, and discussed the physical reasons behind the failure of Gao et al.'s and Simunek and Vackar's (SV) models.
Journal ArticleDOI
Durability of Ni anodes during reoxidation cycles
TL;DR: In this article, the authors provide an overview of the various approaches to the redox problem by summarizing many of the contributions, starting with a basic understanding of the underlying physicochemical processes of Ni reduction and oxidation and ending at stack-level results, leading finally to their combination with recent findings.
Journal ArticleDOI
High-pressure structural, elastic, and electronic properties of the scintillator host material KMgF3
G. Vaitheeswaran,V. Kanchana,Ravhi S. Kumar,Andrew Cornelius,Malcolm Nicol,Axel Svane,Anna Delin,Börje Johansson,Börje Johansson +8 more
TL;DR: In this article, the high-pressure structural behavior of the fluoroperovskite KMgF3 was investigated by theory and experiment, and the ground state properties-the equilibrium lattice constant, bulk modulus, and elastic constants-were in good agreement with experimental results.
Journal ArticleDOI
Chemical bonding and electronic-structure in MAX phases as viewed by X-ray spectroscopy and density functional theory
TL;DR: In this article, a critical review of MAX-phase carbides and nitrides from an electronic-structure and chemical bonding perspective is presented, and the trend and relationship between the chemical bonding, conductivity, elasticity, magnetism and other material properties of the MAX phases in comparison to the parent binary MX compounds with the underlying electronic structure probed by polarized X-ray spectroscopy.
Journal ArticleDOI
The fracture toughness of bulk metallic glasses
TL;DR: In this article, the authors review the available literature to summarize the current understanding of the mechanics and micromechanisms of BMG toughness and highlight the needs for future research in this important area.
References
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Journal ArticleDOI
Beitrag zur Theorie des Anlaufvorgangs
TL;DR: The Mechanismus des Diffusionsvorgangs is still weitgehend unbekannt as discussed by the authors, i.e., the Diffusion of mindestens einem der beiden Bestandteile durch die Anlaufschicht is notwendig.
Journal ArticleDOI
The diffusion of 63Ni along grain boundaries in nickel oxide
A. Atkinson,R. I. Taylor +1 more
TL;DR: The product of the grain boundary diffusion coefficient and width, D′δ, has been measured directly for the diffusion of 63Ni along grain boundaries in high-purity NiO as discussed by the authors.
Journal ArticleDOI
The role of oxide microstructure and growth stresses in the high-temperature scaling of nickel
F. N. Rhines,J. S. Wolf +1 more
TL;DR: In this article, the formation of new nickel oxide upon boundaries of columnar grains where nickel diffusing through the oxide crystals, meets oxygen, diffusing along grain boundaries is identified as the primary cause of this stress.
Journal ArticleDOI
The diffusion of Ni in the bulk and along dislocations in NiO single crystals
A. Atkinson,R. I. Taylor +1 more
TL;DR: In this paper, diffusion profiles of 63Ni tracer in single crystals of NiO following anneals at 522°-1000°C have been determined by a radio-frequency sputter-sectioning technique.
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