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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Journal ArticleDOI
Electronic mechanism for toughness enhancement in Ti x M 1 − x N ( M = Mo and W)
TL;DR: In this article, the authors used ab initio density-functional theory calculations to investigate the mechanical properties of wear-resistant coatings and found that hardness is one of the most important properties.
Journal ArticleDOI
Physical and mechanical properties of single crystals of the T2 phase in the Mo–Si–B system
TL;DR: The T2 phase in the Mo-Si-B system is a refractory molybdenum borosilicide with great potential for ultra-high temperature structural applications.
Book ChapterDOI
Grain-Boundary Diffusion Kinetics in Silicate and Oxide Minerals
TL;DR: The role of grain boundary diffusion along grain boundaries in metamorphic processes is investigated in this paper, where the authors assess the role of such diffusion in metasomatic phenomena and explore the scale of mass transport by grain-boundary diffusion at geologic time scales.
Journal ArticleDOI
Growth Rates of Alumina Scales on Fe–Cr–Al Alloys
TL;DR: In this paper, it was shown that for ideal gas-tight α-Al2O3 scales a near-cubic time dependence is more a rule than an exception, although the frequently used methods for evaluating measured oxidation data might lead to the erroneous conclusion that the scale growth is governed by a transient-oxidation stage followed by parabolic oxidation.
Journal ArticleDOI
Structural and elastic properties of cubic and hexagonal TiN and AlN from first-principles calculations
Aijun Wang,Shun Li Shang,Yong Du,Yi Kong,Lijun Zhang,Lijun Zhang,Li Chen,Dongdong Zhao,Zi Kui Liu +8 more
TL;DR: In this article, the structural and elastic properties of polycrystalline aggregates including bulk modulus (B), shear modulus, Poisson's ratio, and anisotropy ratio are determined and compared with the experimental and theoretical results available in the literature.
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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