M. Golozar

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Papers by M. Golozar

Ti-Microalloyed Steel, Quenched From Hot Forging Temperature

ABSTRACf The aim of the paper presented here is to develop the Ti-micralloyed Steel in otrer to O... more ABSTRACf The aim of the paper presented here is to develop the Ti-micralloyed Steel in otrer to Oprtmize the mechanical Properties after direct quenching from hot forging temperature. For this purpose, Seven melts containing various amounts of titanium were prepared and cast in metal and sand molds. From the ingots, cast in metal mould, tractor links were produced by hot forging. The produced links were direct quenched from forging temperature and then temperd to obtaine the optimum microstructure and mechanical properties. The results obtained from tensile, impact and hardness tests along with the optical and scanning electron microscopy examination showed that the optimum microstructure and thus the optimum mechanical properties belong to 0.01 wt% Titanium-microalloyed steel.

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Nano zirconium oxide/carbon black as a new electrode material for electrochemical double layer capacitors

Journal of Power Sources, 2012

In this paper, nano ZrO 2 /carbon black was evaluated as a possible electrode candidate material ... more In this paper, nano ZrO 2 /carbon black was evaluated as a possible electrode candidate material for electrochemical capacitors. Mechanical pressing as a fast and easy method was used for electrode fabrication. Regarding the utility in supercapacitors, the electrochemical properties of the produced nanocomposite was studied using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests in 2 M KCl, KOH and NaNO 3 electrolytes. Scanning electron microscopy (SEM) was used to characterize the microstructure and nature of the nanocomposite produced. The results obtained show that the 30:60:10 (carbon black:ZrO 2 :polytetrafluoroethylene) type electrode has a specific capacitance as high as 43.20 F g −1 , in the potential range of −0.15 to 0.55 V (vs. SCE) in 2 M KCl at scan rate of 10 mV s −1. SEM images confirm the porous structure of ZrO 2 /carbon black nanocomposite electrode. Also, charge/discharge cycling test shows a good reversibility and confirms that the electrical resistance would increase after 100 cycles.

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&1 22 33 4 ** 56" !!7 8 4 Grafting of Maleic Anhydride onto Co(propylene-b-ethylene) by Extrusion Process: Measurement of Adhesion to Steel Surface

Polypropylene (PP) has poor adhesion to metals and other surfaces for its chemical structure. Hen... more Polypropylene (PP) has poor adhesion to metals and other surfaces for its chemical structure. Hence, chemical * %. /01 # modification of PP is necessary for metal surface coating application. In this research, grafting of maleic anhydride (MA) onto co (propylene-b-ethylene) in the presence of a dicumyl peroxide (DCP) was accomplished in a single screw extruder. Characteristics of the modified polymer were determined by Infra-red Spectroscopy (IR), Scanning Electron Microscopy (SEM), and adhesion test. Maximum grafting of MA was found to be 1.2832% for 1.5 pph of MA. Adhesion test showed that the samples containing 1 pph of MA (degree of grafting is 0.5816%) had better adhesion to steel surface (17.25 kgf).

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Effects of DC Stray Current on Concrete Structure

Effects of DC stray current on concrete structures were studied concentrating on effect of concre... more Effects of DC stray current on concrete structures were studied concentrating on effect of concrete, instead of effects on corrosion of steel bars. Concrete samples prepared with different water/cement (w/c) ratio and silica fume content were submerged in distilled water for 30 days while subjected to the application of a voltage of 50 VDC. The effects DC stray current on the properties of concrete were determined by resistivity, Electrochemical Impedance Spectroscopy, chloride diffusion depth and Rapid Chloride Penetration tests. The results showed DC stray current increased permeability of the concrete. The critical role of w/c ratio and silica fume additive on the degradation effects created by DC stray current was investigated. A mechanism based on the migration of calcium and hydroxyl ions out of the pore solution and the dissolution of Ca(OH) 2 precipitates from the hydrated phase was proposed for the explanation of DC potential on the degradation of concrete.

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‫ﻣﻬﻨﺪﺳﻲ‬ ‫ﺩﺭ‬ ‫ﭘﻴﺸﺮﻓﺘﻪ‬ ‫ﻣﻮﺍﺩ‬ ‫ﺳﺎﻝ‬ ، ۳۲ ‫ﺷﻤﺎﺭﺓ‬ ، ٢ ، ‫ﭘﺎﻳﻴﺰ‬ ١٣٩٢ ٨٩ : Effect of potential on composition and depth profiles of passive films formed on 316L in 0.05M sulfuric acid

In this study, effect of potential on composition and depth profiles of passive films formed on 3... more In this study, effect of potential on composition and depth profiles of passive films formed on 316L stainless steel in 0.05 M sulfuric acid has been examined using X-ray photoelectron spectroscopy (XPS). For passive film formation within the passive region, four potentials-0.2, 0.2, 0.5, and 0.8 V SCE were chosen and films were gown at each potential for 60 min. XPS analysis results showed that atomic concentration of Cr and Fe initially increase (E < 0.5 V SCE) and then decrease with potential. This decrease is due to surface dissolution of the Fe and Cr oxides. For both alloying elements, Ni and Mo, no obvious change in atomic concentration was showed. Results indicated that at higher potentials, before entering transpassive region, oxidation of Cr 3+ to Cr 6+ is happened.

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SiO2 optical layers containing ZnO microparticles produced by the sol-gel method

Dans ce travail, on a etudie la possibilite d'obtenir des couches optiques deposees en employ... more Dans ce travail, on a etudie la possibilite d'obtenir des couches optiques deposees en employant une methode sol-gel. A cet effet, on a utilise une methode sol-gel pour deposer des couches de SiO 2 contenant des quantites variables de microparticules de ZnO sur des substrats de verre sodo-calcique. On a etudie les prorietes optiques de ces echantillons par spectrosccopie optique et on a compare les resultats. Differentes solutions de sols de SiO 2 avaient ete preparees a cet effet et l'on leur a ajoute des quantites variables de micropoudres de ZnO. Les substrats de verre ont ensuite ete trempes dans le melange. Apres sechage a l'autoclave, les echantillons ont ete frittes a 600 °C. Finalement, on a etudie les spectres de reflexion de chaque echantillon par spectrometrie optique dans les domaines de longueur d'ondes du visible. Les resultats montrent que l'accroissement de teneur en microparticules de ZnO dans la solution fait croitre le coefficient de relexion d...

The Influence of Anodising Voltage on Tribocorrosion Behavior of Anodized Ti-6Al-4V Alloy

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Study of alumina sealing of HVOF thermally sprayed WC-Co coatings by sol-gel method

Materials Research Express, 2019

Tungsten carbide (WC) has been known as a hard and wear resistant material. Thermal spray coating... more Tungsten carbide (WC) has been known as a hard and wear resistant material. Thermal spray coatings were used widely to deposit Ni and/or Co based WC. The high-velocity oxy-fuel (HVOF) spraying is one of the best methods among thermal spray processes that creates denser coatings with less pores for high corrosive environments applications. In this study, the effect of alumina sealing process on the HVOF WC-12Co coatings by the Sol-Gel method for corrosion and wear properties at high temperature applications was investigated. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were utilized to characterize the morphology and properties of the coatings before and after the sealing process. High temperature wear properties of coatings before and after sealing were tested by ball-on-disk wear tester at 400 °C. The cross- section of the sealed coatings showed that open pores were filled after sol gel. The thickness of the sealed layer was about 14 μm. Results indicated that the...

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Effects of AC Stray Current on Concrete Structures

Characterization of PLGA/Chitosan Electrospun Nano-Biocomposite Fabricated by Two Different Methods

International Journal of Polymeric Materials and Polymeric Biomaterials, 2014

ABSTRACT Nano-biocomposites composed of poly (lactide-co-glycolide) (PLGA) and chitosan (CS) were... more ABSTRACT Nano-biocomposites composed of poly (lactide-co-glycolide) (PLGA) and chitosan (CS) were electrospun using two fabrication methods. In the single nozzle method, the CS nano-powders dispersed in PLGA solutions were electrospun through a single nozzle but in the double-nozzle method, PLGA and CS were simultaneously electrospun from two syringes and the electrospun PLGA nanofiber and electrosprayed CS nanoparticles were mixed and collected on the rotating drum (randomly oriented [A] and aligned [B]) to prepare the nano-biocomposite membrane. The PLGA/CS scaffolds were prepared at the different ratios. The single-nozzle method was associated with decreasing fiber diameter when the CS content was increased and exhibited improve mechanical and hydrophilic properties.

Effects of Some Parameters on Particle Size Distribution of Chitosan Nanoparticles Prepared by Ionic Gelation Method

Journal of Cluster Science, 2013

ABSTRACT In this research, chitosan nanoparticles were prepared based on the ionic gelation of ch... more ABSTRACT In this research, chitosan nanoparticles were prepared based on the ionic gelation of chitosan with tripolyphosphate anions. Effects of parameters such as chitosan concentration, tripolyphosphate concentration, and reaction time on the particle size distribution were investigated. In order to determine optimum conditions, tests were designed by Qualitek-4 software, using Taguchi method. The best conditions were determined based on three factors at three levels. Therefore, the main object was to investigate the effect of some parameters on particle size distribution and determine the optimum conditions for preparing chitosan nanoparticles by ionic gelation, followed by evaluation of the physicochemical and structural properties. The size distribution of original chitosan and chitosan nanoparticles were determined by Laser Diffraction and Dynamic Light Scattering, respectively. The physicochemical properties of the chitosan nanoparticles were studied using SEM, TEM, XRD pattern, FTIR, UV–vis, TGA, and NMR spectra. The optimum chitosan concentration, tripolyphosphate concentration, and reaction time were found to be 1.0 mg/ml, 1.0 mg/ml, and 60 min, respectively.

The Role of Texture and Microstructure in Optimizing the Corrosion Behaviour of Zinc Hot-dip Coated Steel Sheets

ISIJ International, 2008

Protective metallic coatings based on Zn are usually used to protect steel against corrosion. Whe... more Protective metallic coatings based on Zn are usually used to protect steel against corrosion. When coated steel sheets are subjected to corrosive environments, its corrosion behaviour is affected due not only to changes of the coating texture, but also of the microstructure. The aim of this work was to study the effects of texture components and microstructure on the corrosion behaviour of hot-dip galvanized coatings. Texture components of the coatings were evaluated employing X-ray diffraction whilst its corrosion resistance was analyzed by means of Tafel polarization and salt spray tests. Microstructure of the coatings was studied using SEM and EDS analysis. From the experimental results, it was concluded that increasing the lead content of the zinc bath would decrease the texture coefficient of basal plane component and conversely, the texture coefficient of other components such as high angle pyramids, low angle pyramids and prism planes would be increased. Besides, gamma layer thickness increases as the lead content of the zinc bath increases. In addition, it was observed that greater basal texture coefficient and smaller gamma layer thickness would result in better corrosion resistance of hot-dip galvanized coatings.

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Characterizing organic particle impacts on inert metal surfaces: Foundations for capturing organic molecules during hypervelocity transits of Enceladus plumes

Meteoritics & Planetary Science

The presence and accessibility of a sub-ice-surface saline ocean at Enceladus, together with geot... more The presence and accessibility of a sub-ice-surface saline ocean at Enceladus, together with geothermal activity and a rocky core, make it a compelling location to conduct further, in-depth, astrobiological investigations to probe for organic molecules indicative of extraterrestrial life. Cryovolcanic plumes in the south polar region of Enceladus enable the use of remote in situ sampling and analysis techniques. However, efficient plume sampling and the transportation of captured organic materials to an organic analyzer present unique challenges for an Enceladus mission. A systematic study, accelerating organic ice-particle simulants into soft inert metal targets at velocities ranging 0.5-3.0 km s À1 , was carried out using a light gas gun to explore the efficacy of a plume capture instrument. Capture efficiency varied for different metal targets as a function of impact velocity and particle size. Importantly, organic chemical compounds remained chemically intact in particles captured at speeds up to~2 km s À1. Calibration plots relating the velocity, crater, and particle diameter were established to facilitate future ice-particle impact experiments where the size of individual ice particles is unknown.

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Study on the Effect of Annealing Process on Microstructure and Electrochemical Behavior of the Binary Mn-Ni Nano-Oxide Pseudocapacitor Synthesized by Anodic Deposition

Journal of Advanced Materials In Engineering

In the present investigation, Mn-Ni binary nano-oxide was deposited by potentiodynamic method on ... more In the present investigation, Mn-Ni binary nano-oxide was deposited by potentiodynamic method on stainless steel at room temperature and the effect of annealing process (at 200 o C for 6 h) on microstructure and electrochemical performance of the synthesized pseudocapacitor was studied. The results showed the significant effect of annealing process on increasing the capacitance and decreasing the charge transfer resistance of the electrode. Field Emission Scanning Electron Miscroscopy (FESEM) images depicted interconnected and random nano-flakes in the oxide film microstructure. Moreover, a partially crystallized structure consisting disorder hexagonal birnessite type phase was formed upon annealing in the deposited oxide film with about 10 %at Ni in composition. Based on the galvanostatic charge-discharge plots, the highest specific capacitance (384 F g-1) and specific energy (53 Wh kg-1) were found at specific current of 0.1 A g-1 for the annealed oxide electrode. Finally, cycle life test results at specific current of 10 A g-1 showed an excellent cyclability and an increase of about 23% in specific capacitance of synthesized pseudocapacitor after 5000 charge-discharge cycles in 1 M Na2SO4.

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Wear behaviour of aluminium matrix TiB 2 composite prepared by in situ processing

Materials Science and Technology, 2003

ABSTRACT The wear behaviour and microstructure of aluminium and Al-12Si alloy (A413) matrix compo... more ABSTRACT The wear behaviour and microstructure of aluminium and Al-12Si alloy (A413) matrix composites containing 1 and 5 vol.-%YoTiB(2) particles have been investigated. The composites were prepared by an in situ reactive slag technique. The wear surfaces and wear products were studied after reciprocating and rolling-sliding tests. Wear resistance increased with increasing particle content, and the Al-12Si composites were more wear resistant than those with Al matrixes. The wear mechanisms are briefly discussed.

Effects of remelting processes on porosity of NiCrBSi flame sprayed coatings

Surface Engineering, 2015

Effect of texture on corrosion resistance of hot-dip galvanized coatings

Effect of production parameters on the texture, corrosion behaviour and alloying layers thickness of hot-dip galvanized coatings

A comprehensive study on the effect of production parameters on the structure and properties of hot-dip galvanized coatings

Influence of V2O5 as an effective dopant on the microstructure development and magnetic properties of Ni0.64Zn0.36Fe2O4 soft ferrites

Materials Characterization, 2008

This paper focuses on the effect of vanadium oxide (V2O5) on the magnetic properties and microstr... more This paper focuses on the effect of vanadium oxide (V2O5) on the magnetic properties and microstructural development of Ni0.64Zn0.36Fe2O4 soft ferrite. The ferrite was doped with V2O5, in the range from 0 to 3.2wt.% in steps of 0.4wt.%. The results show that increasing the amount of this oxide up to a certain percentage (1.6wt.%), the permeability, relative density and grain

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