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  • List of Articles


      • Open Access Article

        1 - Investigation of corrosion behavior of galvanized mild steel by improved Zn acidic bath, containing nano-ZnO particles
        Behrooz Shayegh
        In this study, nano-ZnO particles were deposited on mild steel sheets from an acidic zinc bath. These particles were synthesized by using an auto combustion technique. The effect of concentration of nano- ZnO particles on the corrosion behavior of depositions was invest More
        In this study, nano-ZnO particles were deposited on mild steel sheets from an acidic zinc bath. These particles were synthesized by using an auto combustion technique. The effect of concentration of nano- ZnO particles on the corrosion behavior of depositions was investigated. The results of salt spray tests and electrochemical measurements showed that corrosion resistance is improved by addition of nano-ZnO particles into acidic zinc bath. Based on results, coating contain 0.5g of zinc oxide nano-particles had lowest corrosion rate (1.022mpy) and high corrosion resistance. Scanning electron microscopy (SEM) and X- ray diffraction (XRD) were used for studying the surface morphology and crystal structure of the zinc deposit. SEM observations showed that zinc-oxide nano-particles by absorption of the corrosive agents had action as a barrier against corrosive environment. The study of XRD pattern showed that the adding of nano ZnO was decreased the amount of corrosion products which indicated a higher corrosion resistance than the sample without any nano-particles. Manuscript profile
      • Open Access Article

        2 - Editorial Board
      • Open Access Article

        3 - In vitro behavior of silk fibroin-coated calcium magnesium silicate scaffolds
        Masoud Hafezi Hossein Mohammadi Ali Nadernezhad Pardis Fazlali Noor Azuan Abu Osman
        Bioceramic scaffolds such as silicate bioceramics have been widely used for bone tissue engineering. However, their high degradation rate, low mechanical strength and surface instability are main challenges compromising their bioactivity and cytocompatibility which furt More
        Bioceramic scaffolds such as silicate bioceramics have been widely used for bone tissue engineering. However, their high degradation rate, low mechanical strength and surface instability are main challenges compromising their bioactivity and cytocompatibility which further negatively affect the cell growth and attachment. In this study, we have investigated the effects of silk fibroin coating on the tricalcium magnesium silicate scaffolds in term of biological behavior for bone tissue engineering. The microstructure, morphology, cell adhesion and chemical composition of coated scaffolds were analyzed by scanning electron microscopy and Fourier transform infrared spectroscopy. Also, MTT assay test showed that both coated and uncoated scaffolds supported growth of mouse embryonic fibroblast cell. However, the coated scaffold revealed a higher cell proliferation than uncoated one. All the results postulated that silk fibroin was successfully coated on the scaffold and improved the biological properties of scaffold indicating a promising biomaterial for bone tissue engineering application. Manuscript profile
      • Open Access Article

        4 - Fabrication and Characterization of Nanostructure Functionally Graded Ni-P Electroless Coating
        Sayede Razieh Anvari Sayed Mahmoud Monirvaghefi Mohammad Hossein Enayati
        In this research, novel functionally graded Ni-P coating was deposited with electroless process. The content of phosphorus was controlled to change gradual through the thickness of the coating. During the plating, bath temperature and pH were changed at specified interv More
        In this research, novel functionally graded Ni-P coating was deposited with electroless process. The content of phosphorus was controlled to change gradual through the thickness of the coating. During the plating, bath temperature and pH were changed at specified intervals to obtain functionally graded structure. To compare the properties of functionally graded coating with Ni-P single-layer coatings, three types of coatings with different phosphorus contents were also deposited. Microstructure and phase composition of coatings were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffractometry (XRD). The mechanical properties and tribological behavior of coatings were also investigated. Low phosphorus and medium phosphorus single-layer coatings had fully crystalline and amorphous-crystalline structures, respectively. While high phosphorus coating appeared to have a fully amorphous structure. TEM images showed that low phosphorus coating had nano-crystalline structure. Results of nano-indentation test showed gradual changes in hardness profile in cross-section of functionally graded coating due to the gradual changes of phosphorus content in the thickness of this coating. According to the wear test data, medium phosphorus coating had minimum wear resistance. Functionally graded coatings had better wear resistance than single-layer coatings. Manuscript profile
      • Open Access Article

        5 - Plastic deformation of 7075 Aluminum Alloy using Integrated Extrusion-Equal Channel Angular Pressing
        mehdi shaban sahel gozalzadeh beitallah eghbali
        Grain refinement improves the mechanical properties and formability of metals and alloys. So far, several different grain refinement methods have been proposed and studied. Severe plastic deformation is one of the most promising and efficient methods. Therefore, in the More
        Grain refinement improves the mechanical properties and formability of metals and alloys. So far, several different grain refinement methods have been proposed and studied. Severe plastic deformation is one of the most promising and efficient methods. Therefore, in the present study the possibility of imposing a two-step severe plastic deformation (Extrusion and Equal channel angular pressing) on AA7075 alloy using a special designed die is investigated. Using this method, a very coarse grained microstructure with grain size of 94µm is refined to grain size of 7.5µm. Also, microstructural developments during severe deformation with and without preheating are investigated. Plastic strain distribution and temperature variation inside deformed samples are predicted by the use of thermal coupled displacement 3D finite element method. Results of FEM simulations clearly showes that the plastic strain distribution and temperature is non-uniform in sample and this introduces inhomogeneity in the resultant microstructure of sample at different regions. Manuscript profile
      • Open Access Article

        6 - Effects of Friction Stir Process Parameters on Microstructure and Mechanical properties of Aluminum Powder Metallurgy Parts
        Mohsen Abbasi-Baharanchi Fathallah Karimzadeh Mohammad Hossein Enayati
        The effects of friction stir processing (FSP) on the microstructure and mechanical properties of aluminum powder metallurgy (PM) parts was investigated. PM parts were then subjected to FSP at advancing speeds (v) of 40-200 mm/min and tool rotational speeds (ω) of More
        The effects of friction stir processing (FSP) on the microstructure and mechanical properties of aluminum powder metallurgy (PM) parts was investigated. PM parts were then subjected to FSP at advancing speeds (v) of 40-200 mm/min and tool rotational speeds (ω) of 800-1600 rpm. Microhardness (HV) and tensile tests at room temperature were used to evaluate the mechanical properties of the friction stir processed specimens. In order to evaluate microstructure of processed zone, cross-sections of FS processed specimens were observed optically. Based on the results obtained from investigation of the Zener-Holloman parameter (Z), average grain size decreased with decreasing working temperature and increasing working strain rate (equal to increasing Z). The finest grain size was ~ 5.4µm obtained at ω=1000 and v =100 mm/min corresponding to a strain rate of 27s-1 at 414 . This sample exhibited, the best mechanical properties with microhardness, yield stress, and tensile strength of the 43 Hv, 82 MPa, and 118.3 MPa, respectively. Manuscript profile
      • Open Access Article

        7 - Effect of Heat Treatment Time on the Characteristics of Coating Formed on Nanocrystalline Finemet Foils
        Sima Mirzaei Ali Jazayeri Gharehbagh
        In the present research, amorphous Fe73.5Si13.5B9Nb3Cu1 Finemet foils, 21-26µm in thickness and 5mm in width, were prepared by Planar Flow Casting (PFC) process. Wound cores of amorphous Finemet foils were simultaneously annealed and heat treated at 540°C for More
        In the present research, amorphous Fe73.5Si13.5B9Nb3Cu1 Finemet foils, 21-26µm in thickness and 5mm in width, were prepared by Planar Flow Casting (PFC) process. Wound cores of amorphous Finemet foils were simultaneously annealed and heat treated at 540°C for 60, 120 and 240 minutes in steam and air flow to form oxide insulating coating layer on both surfaces of the foils. The structure of nanocrystalline foils was examined by X-ray diffractometry (XRD). The thickness and chemical composition of the insulating coating layer were studied by Field Emission Scanning Electron Microscopy (FE-SEM), Grazing Incidence XRD (GI-XRD) and Fourier Transform Infrared Spectroscopy (FTIR) techniques. The results show that the coating thickness formed on air and wheel surfaces of the foil was in the range of 65-310 nm and these thin coating layers contain a mixture of iron, silicon, boron and niobium oxides. The study of magnetic properties in amorphous and nanocrystalline states revealed that nanocrystalline cores have superior soft magnetic properties compared with the amorphous ones. In other words, the heat treatment gives rise to a decrease in hysteresis loss and a significant increase in saturation induction and magnetic permeabilities. Manuscript profile