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oxide-ceramics
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Investigating the Joining between Silicon Carbide and Aluminum Oxide Using Separate Metal Layers
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor)
Abstract
Sometimes, some ceramics and metals cannot be produced in an integrated manner; In addition, ceramics, like metals, do not fully benefit from the properties of melting and casting; Therefore, it is necessary to produce this group of parts with other methods such as joining to each other. By using joining methods and technologies, it is possible to make composite materials; Therefore, in this way, the applications of ceramic or metal composites have been increasingly expanded. In many researches, bonding of oxide ceramics such as aluminum oxide to itself as well as carbide ceramics such as silicon carbide to itself have been investigated. In this research, the bonding mechanisms of two types...
Synthesis and morphology optimization of electrospun SiBNC nanofibers
, Article Ceramics International ; Volume 46, Issue 5 , 2020 , Pages 6052-6059 ; Mehdinavaz Aghdam, R ; Shahedi Asl, M ; Faghihi Sani, M. A ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
SiBNC nanofibers were synthesized through the polymeric route by a one-pot synthesis approach. DMTA (dichloroboryl methyl trichlorosilyl amine) polymer was selected as pre-ceramic for SiBNC, which was shaped into nanofibers by electrospinning. Then, the nanofibers were cured in an inert atmosphere in order to obtain the final ceramic. By changing the curing atmosphere, the compound of final ceramic has been manipulated. In addition, the ceramic yield of DMTA as a preceramic was increased in the nitrogen atmosphere. The effects of applied voltage, solution concentration, and feeding rate on the morphology of final electrospun ceramic nanofibers were also investigated. Final ceramic remains...
Hydroxyapatite nanocomposites: Synthesis, sintering and mechanical properties
, Article Ceramics International ; Volume 39, Issue 3 , April , 2013 , Pages 2197-2206 ; 02728842 (ISSN) ; Eskandari, A ; Baroonian, M. H ; Berenov, A ; Razavi Hesabi, Z ; Taheri, M ; Sadrnezhaad, S. K ; Sharif University of Technology
2013
Abstract
Two different hydroxyapatite based composites reinforced by oxide ceramic (20 wt%) nano crystals were synthesized by high-energy ball milling and sintered by pressure less technique. Alumina and titania nanoparticles as secondary phases improved densification and mechanical behavior of apatite and postponed its decomposition to the tricalcium phosphate (TCP) phases at elevated temperatures. Increasing the relative density of apatite using nano reinforcements leads to enhance the bending strength by more than 40% and 27% (as compared to the pure HA) and increase the hardness from 2.52 to 5.12 (Al2O3 composite) and 4.21 (TiO2 addition) GPa, respectively. Transmission electron microscopy (TEM),...
Effect of SiO2 content on Y-TZP/Al2O3 ceramic-nanocomposite properties as potential dental applications
, Article Ceramics International ; Volume 46, Issue 8 , 2020 , Pages 10910-10916 ; SharifianJazi, F ; Esmaeilkhanian, A ; Moradi, M ; Safi Samghabadi, A. H ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) have been widely applied in fixed partial prostheses as well as dental uses i.e. a substructure for crowns. However, Y-TZP has limited applications, which is due to the presence of defects in its microstructure introduced during the manufacturing process. Accordingly, due to Y-TZP limitations, the novel (X)Y-TZP- 20Al2O3-(80-X) SiO2 (X = 65, 70 and 75) ceramic nanocomposites were successfully fabricated via the powder metallurgy method. X-ray diffraction (XRD) patterns of commercial powders showed the stabilization of monoclinic zirconia (ZM) by increasing the silica content. In order to determine the fracture load and micro-bending...
Magnetic CoFe2O4 nanoparticles doped with metal ions: A review
, Article Ceramics International ; Volume 46, Issue 11 , 2020 , Pages 18391-18412 ; Moradi, M ; Parvin, N ; Nemati, A ; Jafari Rad, A ; Sheysi, N ; Abouchenari, A ; Mohammadi, A ; Karbasi, S ; Ahmadi, Z ; Esmaeilkhanian, A ; Irani, M ; Pakseresht, A ; Sahmani, S ; Shahedi Asl, M ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Ceramic-magnetic nanoparticles (CMNPs) are attracting attention due to their various applications, especially in biomedical industries. Among them, spinel ferrite CMNPs have received considerable deliberations among different spinel metal oxides due to their fascinating characteristics. Spinel ferrite CMNPs are used for enhancement of the applicability of CMNPs without affecting the intrinsic advantages of iron oxide CMNPs. Spinel ferrites with doping agents have useful electrical and magnetic properties in various fields. Moreover, the replacement of metallic atoms in ferrites is promising to manipulate physical characteristics and improve their performance. Among different spinel ferrites,...
Synthesis of narrow band gap (V2O5)x-(TiO2)1-x nano-structured layers via micro arc oxidation
, Article Applied Surface Science ; Volume 256, Issue 9 , 2010 , Pages 2903-2909 ; 01694332 (ISSN) ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
Abstract
V2O5-TiO2 layers with a sheet-like morphology were synthesized by micro arc oxidation process for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Phase structure and chemical composition of the layers were also studied by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques. It was revealed that the composite layers had a sheet-like structure average thickness of which was about 100 nm depending on the applied voltage. The layers consisted of anatase, rutile, and vanadium pentoxide phases fractions of which varied with the applied voltage. The optical properties...
In situ synthesis of nanocrystalline Al6063 matrix nanocomposite powder via reactive mechanical alloying
, Article Materials Science and Engineering A ; Volume 527, Issue 18-19 , 2010 , Pages 4897-4905 ; 09215093 (ISSN) ; Simchi, A ; Kim, H. S ; Sharif University of Technology
2010
Abstract
In this work, nanocrystalline Al6063 composite powder reinforced with nanometric oxide ceramic particles was synthesized via an in situ solid-gas reaction during high-energy mechanical alloying under a mixture of argon-oxygen atmosphere. The effect of oxygen volume fraction on the morphological evolution and microstructural changes during mechanical alloying was studied by various analytical techniques including optical and electron microscopy, X-ray diffraction, laser particle size analysis, apparent density measurement, and microhardness test. The reactive mechanical alloying resulted in the formation of amorphous Al- and Al-Mg-Si-Fe oxides with a size range of 40-100. nm and volume...