Department of Ceramics (1992 - Present)
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Powder Technology
, McGill,
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Powder Technology
Mining and Metallugical, McGill, Montreal, Canada
Powder Technology
Mining and Metallugical, McGill, Montreal, Canada
Powder Technology
Mining and Metallugical, McGill, Montreal, Canada
Powder Technology
Mining and Metallugical, McGill, Montreal, Canada
Metallurgy and Materials Engineering
, University of Tehran, Iran
Metallurgy and Materials Engineering
, University of Tehran, Iran
Research field: powder synthesis and part manufacturing
Expert: Rasoul Sarraf-Mamoory
Phone: +982182883970
Address: Lab 256, Engineering Faculty
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Prof. Rasoul Sarraf-Mamoory was accepted in Tehran University in 1976 and he finished his Bachelor and Master degrees in 1986 in the field of Metallurgical Engineering. He, then, has studied in McGill University, Canada, and was graduated in the field of Powder Technology. From that time, he has been working in Tarbiat Modares University and at the moment he is a full professor as an educator, advisor, and supervisor. Up to now, he has graduated more than 80 Master and more than 15 Ph.D. students. He has published more than 100 ISI papers yet. In addition, he has performed more than 30 projects for different industries in this University. Finally, he with the help of some industrial people has stablished a factory named Alamut Powder Technology in order to supply the requirements of alloy powders and parts via powder technology route.
The synthesis of nanocomposites containing hydroxyapatite and graphene sheets has received much attention recently. Therefore, strategies that improve their properties will be useful. The aim of this study was to investigate the effect of diethylene glycol on the characteristics of hydroxyapatite-reduced graphene oxide powders synthesized by a hydrothermal method (180 oC, 5 h) and the nanocomposites obtained by spark plasma sintering (950 oC, 50 MPa). Graphene oxide, calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as precursors. The characterization methods included electron microscopy, X-ray diffraction, Raman spectroscopy, and indentation technique. Obtained results have shown that the presence of diethylene glycol
In this study, we demonstrate the fabrication of three-dimensional reduced graphene oxide/hydroxyapatite (HA)/Gelatin scaffolds by employing two steps, including a hydrothermal autoclave with hydrogen gas injection to synthesize three-dimensional graphene (3DG)/HA powders and a hydrogel 3D-printing method to fabricate the scaffolds. Evaluations were performed separately for synthesized powders and fabricated scaffolds, which included field emission scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma, Raman spectroscopy, and instrumented compression experiments. The powders characterization resu
In this study, the effect of the argon, nitrogen, and hydrogen gases on the final properties of the reduced graphene oxide- hydroxyapatite nanocomposites synthesized by gas injected hydrothermal method was investigated. Four samples were synthesized, which in the first sample the pressure was controlled by volume change at a constant concentration. In subsequent samples, the pressure inside the autoclave was adjusted by the injecting gases. The initial pressure of the injected gases was 10?bar and the final pressure considered was 25?bar. The synthesized powders were consolidated at 950??C and 2?MPa by spark plasma sintering method. The final samples were subjected to Vickers indentation analysis. The findings of this study indicate that th
In this study, the hydroxyapatite (HA)-reduced graphene oxide (rGO) nanocomposite was investigated for its mechanical properties. The nanocomposite used in this study was made in two stages. The HA-rGO powders were first synthesized by hydrogen gas injected hydrothermal method, and then consolidated by spark plasma sintering. HA-rGO nanocomposite was subjected to Vickers indentation experiments with different loading rates. Various analyzes have been used in this study, including X-rays diffraction, field emission scanning electron microscopy, high-resolution transmission electron microscopy, fast fourier transform, and inverse fast fourier transform. The findings of this study showed that the HA in this nanocomposite was reinforced with rG
In this study, the mechanical behavior of hydroxyapatite (HA) against the Vickers indenter under different loads was investigated. For this purpose, the HA powders were first synthesized by a one-pot solvothermal method. The powders were then subjected to consolidating by the spark plasma sintering (SPS) method for mechanical evaluation. Characterization methods used in this study included X-rays diffraction, field emission scanning electron microscopy, transmission electron microscopy, inductively coupled plasma, energy dispersive X-ray spectroscopy, and Vickers indentation technique. The findings of this study showed that the morphology of the synthesized powders by solvothermal method were rod-shaped and nanometer-sized. As the applied l
In this study, to achieve high transparency of magnesium aluminate spinel, the ready-to-sinter spinel (RSS) powder was sintered by spark plasma sintering (SPS). To prepare the RSS powder, LiF nanopowder was synthesized at diverse temperatures and concentrations on the spinel powder surface (0.7 wt %). The optimal temperature and concentration were achieved to be (60 ?C) and (200 g/l), respectively. Then, the spinel body was fabricated by SPS method. The XRD, BET, ICP, FESEM and TEM analyses were applied for the characterization of the prepared powder. Also, the results of TEM and XRD analysis confirmed the presence of the fluoride light element (LiF compound) on the spinel particles surface. Finally, the final strength and density of
This paper presents research on the synergistic effects of nickel molybdate and reduced graphene oxide as a nanocomposite for further development of energy storage systems. An enhancement in the electrochemical performance of supercapacitor electrodes occurs by synthesizing highly porous structures and achieving more surface area. In this work, a chemical precipitation technique was used to synthesize the NiMoO 4/3D-rGO nanocomposite in a starch media. Starch was used to develop the porosities of the nanostructure. A temperature of 350 C was applied to transform graphene oxide sheets to reduced graphene oxide and remove the starch to obtain the NiMoO 4/3D-rGO nanocomposite with porous structure. The X-ray diffraction pattern of the NiMoO 4
In this study, we demonstrate enhanced mechanical properties of three-dimensional graphene/hydroxyapatite (3DG/HA) nanocomposites by employing the Taguchi method. The hydrothermal process time, the total pressure, the hydrothermal temperature, and the weight percent of graphene to the hydroxyapatite were considered as control parameters. The results showed that all parameters were effective in controlling the process. According to the findings, the hydrothermal temperature had the greatest effect on the results. The predicted strength fracture toughness is 2.08 ? 0.30 Mpa.m0.5, which is within the 90% confidence interval. Microscopic analysis confirmed the presence of graphene sheets with folding and wrinkling in the powders and indicat
In this study, hydroxyapatite-reduced graphene oxide (HA-rGO) powders were first synthesized in situ using a hydrothermal method. These powders were then consolidated using a cold sintering method. The solvent used in this method was water + dimethylformamide + brushite which was added to the powders at different ratios. The sintered samples were then evaluated using X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, high-resolution transmission electron microscopy, and Vickers microindentation. The results of this study showed that the best conditions for the sintering of rGO-HA nanopowders were a temperature of 200 ?C, a holding time of >30 min, and a pressure of 500 MPa. The best mechanical properties were ac
In this study, the mechanical characteristics of hydroxyapatite (HA) against the Vickers indenter under different loads were investigated. For this purpose, the HA powders were first synthesized by a one-pot solvothermal method. The powders were then subjected to consolidating by the spark plasma sintering (SPS) method for mechanical evaluation. Characterization methods used in this study included X-rays diffraction, field emission scanning electron microscopy, transmission electron microscopy, inductively coupled plasma, energy dispersive X-ray spectroscopy, and Vickers indentation technique. The findings of this study showed that the morphology of the synthesized powders by solvothermal method were rod-shaped and nanometer-sized. As the a
The Sr0.95Sm0.0125Dy0.0125□0.025Ti0.90Nb0.10O3?δ/ZrO2 composite was directly prepared through spark plasma sintering. This approach limited the grain growth and facilitated the achievement of a narrow grain size distribution due to fast sintering and ZrO2 effects. Thermal conductivity declined to 1.68 W m−1 K−1, which is the lowest among the reported values for micro-polycrystalline SrTiO3-based structures.
In order to investigate the effect of graphene nanoribbons on the final properties of hydroxyapatite-based nanocomposites, a solvothermal method was used at 180 C and 5 h for the synthesis of graphene nanoribbons–hydroxyapatite nanopowders by employing hydrogen gas injection. Calcium nitrate tetrahydrate and diammonium hydrogenphosphate were used as calcium and phosphate precursors, respectively. To synthesize the powders, a solvent containing diethylene glycol, anhydrous ethanol, dimethylformamide, and water was used. Graphene oxide nanoribbons were synthesized by chemical unzipping of carbon nanotubes under oxidative conditions. The synthesized powders were consolidated by spark plasma sintering methodat 950 C and a pressure of 50 MPa.
Introduction: Indentation (micro and nano) is one of the methods used to study the mechanical properties of brittle materials. This method is performed using various indenters such as Vickers, Cone, and Berkovich. Objective: In this study, bone like materials behavior against Vickers, Cone, and Berkovich indenters was investigated. Material and Methods: In this study, spark plasma sintered hydroxyapatite-reduced graphene oxide nanocomposites were used instead of hard bone. Sintered samples were subjected to indentation technique using Vickers, Cone, and Berkovich indenters for mechanical evaluation. Result: The results showed that each method has different uses and different results. The Vickers method is more suitable for micrometer dimens
In this study, the two-state solvothermal method (180 ?C) was used for the synthesis of hydroxyapatite nanoparticles. The former is traditional (2, 4 h), and the latter, with argon gas injection (10 bar). To synthesize the powders, a solvent containing dimethylformamide, anhydrous ethanol, diethylene glycol, and water was used. Calcium nitrate tetrahydrate and diammonium hydrogen phosphate were used as calcium and phosphate precursors, respectively. The synthesized powders were consolidated by a high-frequency induction heat sintering method. The powders and sintered samples were then evaluated using X-ray diffraction, Raman spectroscopy, high-resolution transmission electron microscopy, and Vickers microindentation technique. The results o
In this study, we show the synthesis of reduced graphene oxide/hydroxyapatite (rGO/HA) composites using a hydrothermal autoclave with argon-15% hydrogen gas injection. This both increases the hydrothermal pressure and uses hydrogen as a reductive agent in the process. The synthesized powders were then consolidated with spark plasma sintering method. The analysis of the consolidated samples included Vickers Indentation technique and cell viability. The results showed that injected gases in the autoclave produced powders with a higher crystallinity compared to synthesis without the gases. Also, hydrogen gas led to increased reduction of GO. The microscopic analysis confirmed existing graphene sheets with folding and wrinkling in the powders a
Introduction: HA and graphene have recently been added to gelatin as reinforcing phases (individually or together). These materials increase the mechanical and biological properties of gelatin and extend gelatin applications as tissue engineering scaffolds. Objective: In this study, the physical properties of these scaffolds were evaluated using scanning electron microscopy by detail. Material and Methods: A hydrogel 3D printing method and freeze- drying were used in this study. The analysis performed in the sample includes X-ray diffraction, Scanning Electron Microscope, and bending. Result: The findings of this study showed that the addition of graphene and HA to gelatin changed the rheology, reduced the size of pores, and increased the a
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