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Interface formation and bond strength in 3Y-TZP/Cr composite bilayers produced by sinter–joining [electronic resource]
, Article Materials Science and Engineering: A ; Volume 527, Issue 3, 15 January 2010, Pages 449–453 ; Simchi, A. (Abdolreza) ; Hokamoto, K ; Tanaka, S ; Sharif University of Technology
Abstract
The mechanism of interface formation during sinter–joining of nanostructured yttria stabilized zirconia (27 nm) compacts with chromium powder was investigated. The effect of sintering atmosphere, i.e. argon or vacuum, was studied. Microstructural evaluation and phase formation was examined by scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and micro-focused X-ray diffraction (MFXRD) methods. It is shown that spreading and evaporation–condensation mechanisms are responsible for the interface formation. An improved joint shear-strength was obtained after sintering in vacuum (74 MPa) compared with argon (41 MPa). The result of MFXRD indicated formation of Cr-island at...
Interface formation and bond strength in 3Y-TZP/Cr composite bilayers produced by sinter-joining
, Article Materials Science and Engineering A ; Volume 527, Issue 3 , 2010 , Pages 449-453 ; 09215093 (ISSN) ; Simchi, A ; Hokamoto, K ; Tanaka, S ; Sharif University of Technology
Abstract
The mechanism of interface formation during sinter-joining of nanostructured yttria stabilized zirconia (27 nm) compacts with chromium powder was investigated. The effect of sintering atmosphere, i.e. argon or vacuum, was studied. Microstructural evaluation and phase formation was examined by scanning electron microscopy (SEM), electron probe micro-analysis (EPMA), and micro-focused X-ray diffraction (MFXRD) methods. It is shown that spreading and evaporation-condensation mechanisms are responsible for the interface formation. An improved joint shear-strength was obtained after sintering in vacuum (74 MPa) compared with argon (41 MPa). The result of MFXRD indicated formation of Cr-island at...
Presureless sintering of stainless steels/zirconia composite layers usable for co-powder injection moulding process
, Article Proceedings of the World Powder Metallurgy Congress and Exhibition, World PM 2010, 10 October 2010 through 14 October 2010 ; Volume 2 , 2010 ; 9781899072194 (ISBN) ; Simchi, A ; Hokamoto, K ; Sharif University of Technology
Abstract
Sintering is the most critical step in manufacturing of functional parts by co-powder injection molding. In the present work, we studied the sintering phenomena occurring during co-sintering of metal/ceramic composite layers. Nanostructured yttria-stabilized zirconia (3Y-TZP) was co-sintered with 430L stainless steel and chromium. The sintering response was studied by dilatometer analysis in isothermal and non-isothermal modes. The microstructure of the sintered specimens was studied by scanning electron microscopy (SEM), electron-probe microanalysis (EPMA) and micro-focused X-ray diffraction (MFXRD). The strength of the joint was also determined by a shear-punch method. It is shown that...
Composite Redesigning of a Metallic Wing Structure of a Jet Aircraft
, M.Sc. Thesis Sharif University of Technology ; Hosseini Kordkheili, Ali (Supervisor)
Abstract
Today, for construction of UAV, designers are interested in and trying for substitution of composite material instead of metal. They would rather use composite structures due to lower costs of construction, availability, along with high ratio of strength to weight of this material, while metal structures are mainly rare and too expensive for construction of UAV. For instance, unavailability of aluminum metal and complicated methods of construction of aluminum wings with using of special tools, justifies using of composite with easier construction, abundant, and cheaper materials. The main goal of this project is redesign of aluminum wing of a jet engine UAV, In fact, by doing some structural...
Fabrication of HAp-8YSZ composite layer on Ti/TiO2 nanoporous substrate by EPD/MAO method
, Article Materials Letters ; Volume 65, Issue 23-24 , 2011 , Pages 3421-3423 ; 0167577X (ISSN) ; Moshayedi, Sh ; Ghaffari, S. A ; Rezaei, H. R ; Golestani Fard, F ; Sharif University of Technology
Abstract
Zirconia/Hydroxyapatite composites containing 20-50 wt.% 8YSZ were prepared on Ti/TiO2 substrates by electrophoretic deposition (EPD)/micro-arc oxidation (MAO) process. Titania, as an inner layer, was grown on the Ti plates using MAO treatment in order to form a strong join between substrate and HAp. These composites were produced by EPD in ethanol containing ZrO2/HAp particles at 50, 100 and 150 V in 1 min. Asprepared samples were sintered at 900, 1100 and 1300 °C. HAp, β-TCP, CaZrO3 phases were identified using X-ray diffractometry analysis (XRD). Scanning electron microscopy (SEM) utilized to study the surface morphology indicated a crack free microstructure at 1300 °C
Effect of electrolyte concentration on microstructure and properties of micro arc oxidized hydroxyapatite/titania nanostructured composite
, Article Materials Science and Engineering C ; Volume 33, Issue 5 , 2013 , Pages 2555-2561 ; 09284931 (ISSN) ; Golestani Fard, F ; Mirhosseini, S. M. M ; Ziaee, A ; Mehrjoo, M ; Sharif University of Technology
2013
Abstract
Micro arc oxidation was employed to grow TiO2/hydroxyapatite composite layer on titanium substrate. The correlation between electrolyte concentration, diameter and density of the pores in fabricated layers was investigated. Therefore, the effect of electrolyte concentration on composition and morphology of grown layers was studied using SEM, EDX, XRD and XPS techniques. Samples were coated in electrolytes containing 5, 10 and 15 g/l calcium acetate and 1, 3 and 5 g/l β-glycerophosphate, at optimized voltage for 3 min. Pore size variations obey a similar pattern by the addition of both calcium acetate and β-glycerophosphatein various concentrations based on SEM observations. However,...
Sequential deposition as a route for efficient counter electrodes in quantum dot sensitized solar cells
, Article RSC Advances ; Volume 5, Issue 57 , May , 2015 , Pages 45592-45598 ; 20462069 (ISSN) ; Samadpour, M ; Taghavinia, N ; Sharif University of Technology
Royal Society of Chemistry
2015
Abstract
In this paper, we introduce the sequential deposition method for enhancing the performance of nanocomposite counter electrodes (CEs) in quantum dot sensitized solar cells (QDSCs). Here, various CEs are made by the deposition of CuS, PbS, and CuS/PbS nanocomposite layers on an FTO (fluorine doped tin oxide) coated glass substrate by a simple successive ionic layer adsorption and reaction (SILAR) method. The result indicates that the efficiency of the cells with CuS/PbS CEs is enhanced by 2.65% compared with the bare CuS (0.99%) or PbS (1.47%) CEs. Also, no considerable improvement is observed for PbS/CuS CEs (1.09%), which indicates that the order of PbS and CuS deposition is critical for...
Microstructural and electrical properties of varistors prepared from coated ZnO nanopowders
, Article Journal of Materials Science: Materials in Electronics ; Volume 21, Issue 6 , June , 2010 , Pages 571-577 ; 09574522 (ISSN) ; Maleki Shahraki, M ; Faghihi Sani, M. A ; Nemati, A ; Yousefi, A ; Sharif University of Technology
2010
Abstract
This paper describes a solution-based technique for fabrication of varistor grade composite nanopowders. The method consists of coating major varistor dopants on the surface of the ZnO nanoparticles. As a result, a homogenous mixture of dopants and ZnO nanoparticles will be achieved. TEM results indicated that a composite layer of dopants with the average particle size of 9 nm on the surface of ZnO nanoparticles has been successfully prepared. Sintering of the coated powders was performed in temperatures as low as 850 °C and final specimens with average particle size of 900 nm and density of 98.5% were achieved. In comparison to conventional mixing, varistors prepared from coated nanopowders...
Effect of second-phase particle size and presence of vibration on AZ91/SiC surface composite layer produced by FSP
, Article Transactions of Nonferrous Metals Society of China (English Edition) ; Volume 30, Issue 4 , 2020 , Pages 905-916 ; Abbasi, M ; Abdollahzadeh, A ; Mirsalehi, S. E ; Sharif University of Technology
Nonferrous Metals Society of China
2020
Abstract
An improved method of friction stir processing (FSP) was introduced for the processing of AZ91 magnesium alloy specimens. This novel process was called “friction stir vibration processing (FSVP)”. FSP and FSVP were utilized to develop surface composites on the studied alloy while SiC nanoparticles were applied as second-phase particles. The effect of reinforcing SiC particles with different sizes (30 and 300 nm) on different characteristics of the composite surface was studied. The results indicated that the microstructure was refined and mechanical properties such as hardness, ductility, and strength were enhanced as FSVP was applied. Furthermore, it was concluded that the effect of...
Electrodeposited Ni-Co alloy-particle composite coatings: A comprehensive review
, Article Surface and Coatings Technology ; Volume 382 , 2020 ; Tanhaei, M ; Ahmadipour, M. F ; Ghaffari Adli, R ; Mahdavi, S ; Walsh, F. C ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Electrodeposited composite and nanocomposite layers have attracted considerable attention as engineering coatings, due to their favourable tribological properties and corrosion resistance. Ni[sbnd]Co alloy matrix composite coatings are particularly significant due to their extensive and developing industrial applications. Ceramic nanoparticles are commonly incorporated into the Ni[sbnd]Co alloy matrix to further improve their properties, opening new windows for industrial applications. This review aims to comprehensively assess the influence of operating parameters (including the type of current control, plating bath conditions, particle loading and size) on the deposit properties....
Pressureless sintering of 3Y-TZP/stainless-steel composite layers
, Article Journal of the American Ceramic Society ; Volume 91, Issue 11 , 2008 , Pages 3493-3503 ; 00027820 (ISSN) ; Simchi, A ; Tamjid Shabestary, E ; Hartwig, T ; Sharif University of Technology
2008
Abstract
A pressureless sintering method was utilized to fabricate metal/ceramic joints out of yttria-stabilized zirconia (3Y-TZP) and stainless steels (SS). Ultrafine (150 nm) and nanoscale (75 nm) 3Y-TZP particles and micrometric 17-4PH, 316L, and 420 SS (<31 μm) powders were tested. Isothermal and nonisothermal sintering behaviors of the powders and composite layers in hydrogen, argon, and vacuum atmospheres were examined. It was found that the mismatch strain between the zirconia ceramic and SS during cosintering is significant, which leads to bond cracking and joint failure. Nevertheless, interlayer diffusion of Zr, Fe, and Cr and the formation of a reaction zone, particularly during vacuum...
Self-accumulated Ag nanoparticles on mesoporous TiO2 thin film with high bactericidal activities
, Article Surface and Coatings Technology ; Volume 204, Issue 21-22 , August , 2010 , Pages 3676-3683 ; 02578972 (ISSN) ; Ghaderi, E ; Sharif University of Technology
Abstract
Antibacterial activity of sol-gel synthesized Ag-TiO2 nanocomposite layer (30nm) deposited on rough anatase (a) TiO2 thin film (~200nm in thickness) was investigated against Escherichia coli bacteria, in dark and also in exposure to UV light. The nanocomposite thin films were transparent with a surface plasmon resonance absorption band at a wavelength of 410nm. The metallic silver nanoparticles with an average diameter of 30nm and fcc crystalline structure were self-accumulated on surface of a mesoporous and aqueous TiO2 layer with a capillary pore structure having a pore radius of 3.0nm. By adding the silver nanoparticles in the TiO2 layer, recombination of the photoexcited electron-hole...
Visible photodecomposition of methylene blue over micro arc oxidized WO3-loaded TiO2 nano-porous layers
, Article Applied Catalysis A: General ; Volume 382, Issue 2 , Jan , 2010 , Pages 322-331 ; 0926860X (ISSN) ; Golestani Fard, F ; Moshfegh, A. Z ; Sharif University of Technology
2010
Abstract
WO3-TiO2 nano porous layers were synthesized by micro arc oxidation (MAO) process under different applied voltages in electrolytes containing sodium tungstate and phosphate salts with various concentrations. X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDS) techniques were employed to study phase structure and chemical composition of the layers. According to our data analysis, the nano porous layers consisted of anatase, rutile, and tungsten oxide phases with a varying fraction depending on the voltage and electrolyte concentration. Moreover, it was found that WO3 not only dispersed in the TiO2 matrix, but also doped into the TiO2...
In situ growth of vanadia-titania nano/micro-porous layers with enhanced photocatalytic performance by micro-arc oxidation
, Article Electrochimica Acta ; Volume 55, Issue 9 , 2010 , Pages 3093-3102 ; 00134686 (ISSN) ; Moshfegh, A. Z ; Golestani Fard, F ; Sharif University of Technology
2010
Abstract
Micro-arc oxidation process was used to synthesize V2O5-TiO2 porous layers for the first time. Surface morphology and topography of the layers were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) techniques were also employed to evaluate phase structure and chemical composition of the layers. It was found that the V2O5-TiO2 layers consisted of anatase, rutile, and vanadium pentoxide phases fraction of which varied with the applied voltage and the electrolyte concentration. It was also revealed that pore size and surface roughness increased with the applied voltage and the electrolyte...
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...
Study the sintering behavior of nanocrystalline 3Y-TZP/430L stainless-steel composite layers for co-powder injection molding
, Article Journal of Materials Science ; Volume 44, Issue 5 , 2009 , Pages 1264-1274 ; 00222461 (ISSN) ; Simchi, A ; Sharif University of Technology
2009
Abstract
Recently, co-powder injection molding process (2C-PIM) has attained considerable interest to fabricate complex-shaped functional materials. The aim of this work is to study the sintering compatibility between nanocrystalline yttria-stabilized zirconia (3Y-TZP) and PIM grade 430L stainless steel (SS) powders, which is the utmost important step in the 2C-PIM process. To evaluate the mismatch strain development during the co-sintering, the isothermal and nonisothermal behaviors of the ceramic and metal powders were studied. Small bilayers of 3Y-TZP/430L were made by a powder metallurgy technique and the feasibility of simultaneous sintering and joining of the composite layer was examined....