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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Ab initio calculations of mechanical properties: Methods and applications
Jaroslav Pokluda,Jaroslav Pokluda,Miroslav Černý,Miroslav Černý,Miroslav Černý,Mojmír Šob,Mojmír Šob,Mojmír Šob,Yoshitaka Umeno +8 more
TL;DR: In this article, the authors review a rather extended field of ab initio calculations of mechanical properties of materials and make an overview of advanced approaches to crystal stability, focusing on results of studies on interfaces and grain boundaries.
Journal ArticleDOI
Elastic constants and their temperature dependence for the intermetallic compound Ti3Al
TL;DR: In this paper, singlecrystal elastic contents of Ti3Al have been measured from 3.3 to 290k by a rectangular parallelepiped resonance method, which is interpreted as indicating the existence of directional bonding in the compound.
Journal ArticleDOI
First-principles calculations of pressure and temperature dependence of thermodynamic properties of anti-perovskite BiNBa 3 compound
Kada Bidai,Mohammed Ameri,Slamani Amel,Ibrahim Ameri,Yarub Al-Douri,Yarub Al-Douri,Dinesh Varshney,Chun Hong Voon +7 more
TL;DR: In this paper, the structural, elastic and thermodynamic properties of the antiperovskite BiNBa3 compound are studied under the effects of pressure and temperature using the fullpotential augmented plane wave plus the local orbitals method (FP-APW+lo).
Journal ArticleDOI
Three Dimensional Carbon-Nanotube Polymers
Zhisheng Zhao,Bo Xu,Li-Min Wang,Xiang-Feng Zhou,Julong He,Zhongyuan Liu,Hui-Tian Wang,Yongjun Tian +7 more
TL;DR: Eight fascinating sp(2)- and sp(3)-hybridized carbon allotropes have been uncovered using a newly developed ab initio particle-swarm optimization methodology for crystal structure prediction, and have distinctive electronic properties, high Young's moduli, high tensile strength, ultrahigh hardness, good ductility, and low density.
Journal ArticleDOI
Elastic and electronic properties of Pbca-BN: First-principles calculations
TL;DR: In this paper, the structural, elastic, electronic properties and elastic anisotropy of a fully tetrahedrally bonded boron nitride (BN) allotrope with an orthorhombic structure (Pbca-BN, space group: Pbca) was investigated by first-principles calculations.
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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