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Control of Elements Ratio in Alloy Deposition System
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor)
Abstract
Nowadays, thin film alloy deposition has much importance. These alloys are used for various opto-electronic device applications such as liquid crystal displays, flat panel displays, plasma displays, solar cells and computer memories. Exact control of elements ratio in alloy is one of the important issues in deposition of thin film alloys. In alloy deposition with electron beam gun method from its elements, uniformity improvement of each layer is a way to maintain elements ratio in different parts of sample. This uniformity has much importance especially in optical coatings such as high quality antireflection coatings, highly selective filters and low loss reflectance coatings. In this...
MAO-derived hydroxyapatite/TiO 2 nanostructured multi-layer coatings on titanium substrate
, Article Applied Surface Science ; Volume 261 , 2012 , Pages 37-42 ; 01694332 (ISSN) ; Golestani Fard, F ; Rezaie, H. R ; Mirhosseini, S. M. M ; Sharif University of Technology
2012
Abstract
In this study, titanium substrates which previously oxidized through Micro arc oxidation method, was coated by Hydroxyapatite (HAp) coating once more by means of the same method. Morphology, topography and chemical properties as well as phase composition and thickness of layers were studied to reveal the effect of the electrolyte concentration on coating features. According to results, the obtained coatings are consisted of HAp and titania as the major phases along with minor amounts of calcium titanate and α-tri calcium phosphate. Ca and P are present on surface of obtained layers as well as predictable Ti and O based on the XPS results. Thickness profile of coatings figured out that by...
Small-scale oriented elasticity modeling of functionally graded rotating micro-disks with varying angular velocity in the context of the strain gradient theory
, Article Acta Mechanica ; Volume 232, Issue 6 , 2021 , Pages 2395-2416 ; 00015970 (ISSN) ; Asghari, M ; Kargarzadeh, A ; Badiee, M ; Sharif University of Technology
Springer
2021
Abstract
During the varying angular speed timespans of the start or shutdown of rotating machinery, the machinery components may be subjected to intense mechanical loadings which should be taken into account by its fabricator in the designing processes. In the microscale rotating systems, where the angular velocity is typically very high, the importance of this issue is much higher. In this paper, a comprehensive strain-gradient elasticity formulation is presented for functionally graded rotating micro-disks under the effects of varying angular velocity. The gradation of the constituent material along the radial direction can be a helpful option to mitigate the stresses in rotating micro-disks under...
Three-dimensional elasticity analysis of functionally graded rotating cylinders with variable thickness profile
, Article Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science ; Volume 226, Issue 3 , 2012 , Pages 585-594 ; 09544062 (ISSN) ; Asghari, M ; Sharif University of Technology
Abstract
A three-dimensional elasticity solution for the analysis of functionally graded rotating cylinders with variable thickness profile is proposed. The axisymmetric structure has been divided in several divisions in the radial direction. Constant mechanical properties and thickness profile are assumed within each division. The solution is considered for four different thickness profiles, namely constant, linear, concave, and convex. It is shown that the linear, concave, and convex thickness profiles have smaller stress values compared to a constant thickness profile. The effects of various grading indices as well as different boundary conditions, namely solid, free-free hollow and fixed-free...