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Open Access Article
1 - Investigation of Optimal Milling Conditions in the Production of Mg-3Zn-1Mn Nanocomposite
Saeid jabbarzare Hamid Reza Bakhsheshi Rad Amirabbas Nourbakhsh tahmine ahmadiOne approach for the preparation of Mg-3Zn-1Mn nanobiocomposite is powder metallurgy. After preparing the alloy by the milling process, hardening is conducted during the sintering process. The condition for obtaining high strength and corrosion resistance of as-sintered MoreOne approach for the preparation of Mg-3Zn-1Mn nanobiocomposite is powder metallurgy. After preparing the alloy by the milling process, hardening is conducted during the sintering process. The condition for obtaining high strength and corrosion resistance of as-sintered specimens is the uniform distribution of zinc and manganese elements in the magnesium matrix and the maximum particle size reduction to increase the surface area. In this research, under certain conditions, the milling process has been conducted to fabricate this nanocomposite. The result of XRD analysis exhibited that the optimal sample is obtained after 25 h milling. At this time, the grain size was 27 μm, and the crystallite size was 24 nm. Evaluation of X-ray diffraction (XRD), X-ray fluorescence (XRF), transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HR-TEM), scanning electron microscopy (SEM), and field emission scanning electron microscopy (FE-SEM) results for samples shows uniform distribution of zinc and manganese particles in the matrix of magnesium and confirms the reduction of particle size with spherical shape for nanobiocomposite specimens. Manuscript profile -
Open Access Article
2 - Comparative Study of the Effects of Strontium and Magnesium Ions on Physical and Chemical Properties of Calcium Phosphate-Gelatin Biomimetic Scaffolds in Bone Tissue Engineering
Amirhossein Moghanian Majid Raz Fathollah MoztarzadehIn this study, biomimetic scaffolds were designed to study the formation of calcium phosphate deposits by using a double diffusion method into gelatin hydrogel in temperature and pH similar to body conditions. Moreover, the effect of magnesium (Mg) and strontium (Sr) io MoreIn this study, biomimetic scaffolds were designed to study the formation of calcium phosphate deposits by using a double diffusion method into gelatin hydrogel in temperature and pH similar to body conditions. Moreover, the effect of magnesium (Mg) and strontium (Sr) ions on properties was investigated. Five different types of specimens with different Sr and Mg ions percentage were synthesized and then porous scaffolds were prepared by freeze-drying method. The scaffolds microstructures were examined by scanning electron microscopy (SEM), which showed a smooth and needle-shaped surface of specimens. Fourier transform infrared spectroscopy (FTIR) results indicated the presence of phosphate and hydroxyl bonds in the structure of the scaffolds, due to the formation of calcium phosphate phases such as HA. The presence of metal ions in the structure caused the displacement of the peaks in X-ray diffraction (XRD) analysis and lattice parameters. Additionally, osteoblast cell culture results also demonstrated M10 and S10 specimens had proper biocompatibility. Additionally, alkaline phosphate (ALP) activity revealed the optimal amount of 10 mol. % Mg and Sr (M10 and S10), which led to the significantly (**p< 0.01, ***p <0.001) growth, proliferation, and differentiation of 292G osteoblasts cells in scaffolds. Moreover, the presence of calcium phosphate improved the biological properties of the specimens. Finally, the results of various analyses confirmed the high capability of the synthesized scaffold as a promising substitute for bone tissue. Manuscript profile -
Open Access Article
3 - The Effect of Silicon Carbide Ceramic Nanoparticles on the Tribological Properties of SN500HVI Paraffinic Base Oil
Meisam Makkarian Elham AmeriThe effect of silicon carbide (SiC) nanoparticles on the tribological properties of the base oil was investigated by friction and wear tests. SiC nanoparticles were synthesized by sol-gel method and added to the base oil at various weight percentages of (0.25, 0.5, 1 an MoreThe effect of silicon carbide (SiC) nanoparticles on the tribological properties of the base oil was investigated by friction and wear tests. SiC nanoparticles were synthesized by sol-gel method and added to the base oil at various weight percentages of (0.25, 0.5, 1 and 5). To increase the stability of SiC nanoparticles in the base oil, the surface was modified using oleic acid. To characterize the morphology of SiC nanoparticles, the FT-IR, FESEM and XRD techniques were applied. This investigation was carried out in the base oil SN500HVI from Sepahan Oil Company, Iran. The friction and wear tests were performed on the mixture of SN500HVI/nanoparticles. The tribological properties of nanoparticles in base oil were investigated using pin on disc test according to ASTM G99 test method. Based on the results obtained by XRD, the average size of SiC was known to be less than 30 nm. The mixture of nanoparticles in base oil with concentrations of 0.25, 0.5 and 1 wt.% led to reduction of friction coefficient by 26%, 15%, and 4%, in comparison to pure base oil, respectively. This tribological behavior was due to adhesiveness of nanoparticles on involving surfaces. Furthermore, the topography of worn surfaces was analyzed using FESEM. The results illustrated that the nanoparticles can be an effective additives to improve the quality of lubricants in terms of reducing the friction and wear due to their proper physical properties such as suitable hardness, spherical shape and high specific surface area. Manuscript profile -
Open Access Article
4 - Comparison of Isothermal Oxidation and Thermal Shock Properties of CoNiCrAlY Coating Sprayed by Atmospheric Plasma Spray and Nitrogen Gas Shrouded Plasma Spray Methods
Behzad Ghasemi Zia Valefi Saeid Taghi-ramezaniIn this research, the properties of the coating applied by conventional plasma spray and with inert gas shroud has been studied and compared, in the way that nozzle like part attached to plasma gun in order to protect the plasma jet by exiting nitrogen from the nozzle. MoreIn this research, the properties of the coating applied by conventional plasma spray and with inert gas shroud has been studied and compared, in the way that nozzle like part attached to plasma gun in order to protect the plasma jet by exiting nitrogen from the nozzle. The Microstructural characterization of the coatings was performed by optical microscope and scanning electron microscope equipped with energy dispersive spectroscope. Hardness of coatings is also measured by Vickers method under the applied load of 30 gram-force. Isothermal oxidation and thermal shock tests are done at 1000 and 950ºC respectively. Post-spray results show that the use of nitrogen gas shroud is useful and coating achieved by nitrogen shroud has less oxide and porosity and has more homogeneous structure. Results from isothermal oxidation show that TGO layer growth rate in the specimen sprayed by nitrogen shroud is less. Thermal shock test shows that the specimen sprayed by nitrogen shroud has more resistance against thermal shock due to layer by layer and regular growth of TGO and having less oxide and porosity in comparison with the same specimen sprayed without nitrogen shroud. Also, the microhardness of sprayed coating without nitrogen shroud was 35 Vikers more than the applied coating with nitrogen shroud. Manuscript profile -
Open Access Article
5 - Effects of Heat Treatment on the Microstructure, Mechanical Properties and Corrosion Behavior of 2209 Duplex Stainless Steel Parts Manufactured By Wire Arc Additive Manufacturing Process
Ali A. Molazadeh Kashkouie Mahmood Sharifitabar Mahdi Shafiee AfaraniThe present study deals with the fabrication and investigation of structure, microstructure, mechanical properties and corrosion resistance of 2209 duplex stainless steel parts made by wire arc additive manufacturing method. The formation of ferrite and austenite phases MoreThe present study deals with the fabrication and investigation of structure, microstructure, mechanical properties and corrosion resistance of 2209 duplex stainless steel parts made by wire arc additive manufacturing method. The formation of ferrite and austenite phases was confirmed by XRD analysis. There was a non-uniform distribution of ferrite and austenite phases in the microstructure of the as-welded microstructure. The tensile and Vickers microhardness tests were employed to evaluate mechanical properties. The results showed that the mean values of yield and tensile strengths were respectively 2.7 and 5.5% higher and the elongation was 4.5% lower in the welding direction than the building direction. Post-processing heat treatment at 1000 °C for 30 min led to the grain refinement of the alloy, the formation of equiaxed microstructure, increase in the austenite volume fraction, and increasing the mean hardness from 318 to 376 HV. The fractography of the tensile test specimens revealed the ductile fracture mode in all samples. Corrosion test results showed that the heat treatment improved the corrosion resistance of the alloy. Manuscript profile -
Open Access Article
6 - Synthesis of Zinc Ferrite Ferrofluid and Investigation of its Rheology and Magnetic Properties
Farshid Mahdavi Babak HashemiIn this study, we first synthesized zinc ferrite nanoparticles by using co-precipitation method and adding zinc to iron ferrite in different amounts. Redistribution of Fe and Zn cations in tetrahedral and octahedral locations can significantly alter and increase saturat MoreIn this study, we first synthesized zinc ferrite nanoparticles by using co-precipitation method and adding zinc to iron ferrite in different amounts. Redistribution of Fe and Zn cations in tetrahedral and octahedral locations can significantly alter and increase saturation magnetization. The saturation magnetization of the synthesized ferrite nanoparticles was 57% higher than that of iron ferrite, and the nanoparticles had an average size of 35 nm. The synthesized nanoparticles were then functionalized using oleic acid and polyethylene glycol and three types of stable fluids based on water, engine oil and ethylene glycol were prepared. Optimal Ferro-fluid with the highest stability properties and amount of saturated magnetization was used to investigate the rheological properties. The non-Newtonian behavior of the fluid with different percentages of nanoparticles was investigated and the greatest change in behavior from the Newtonian state was related to the fluid with 15% by volume of nanoparticles. Manuscript profile -
Open Access Article
7 - Optimization the Mechanical Properties of PVC/n-NBR Blends Using Taguchi Experimental Design Method
Alireza Afshari Mohammadreza Kalaee Mehdi MoghriThe aim of this paper is to study the morphology and mechanical properties of poly(vinyl chloride) (PVC) blends containing acrylonitrile butadiene rubber (NBR) nanoparticles prepared in a counter rotating twin- screw extruder. The effect of nanoparticle’s percent, MoreThe aim of this paper is to study the morphology and mechanical properties of poly(vinyl chloride) (PVC) blends containing acrylonitrile butadiene rubber (NBR) nanoparticles prepared in a counter rotating twin- screw extruder. The effect of nanoparticle’s percent, mixing temperature and time and rotor speed on the properties were studied using the experimental design method. Considering toughness increase of the blends as an optimal state, the process conditions and NBR percent were determined. Scanning electron microscopy (SEM) images showed dispersed matrix-droplet morphology. Uniform distribution of NBR rubber particles was observed within the PVC matrix due to the good compatibility between the rubber particles and the matrix. It was also observed that scattered droplets are present in the spherical form as well as elongated particles within the PVC matrix. Obtained results along with experimental design data showed that the optimal state of break strain and toughness is related to the state with a mixing temperature of about 180 °C, mixing time of 6 minutes, mixing speed of about 70 rpm and a nanoparticle percentage of 2%. The analysis of variance showed that the greatest effect on the modulus was related to the percentage of NBR, while the lowest was related to the mixing time. After that, mixing temperature has the highest share. Interactions between different factors and their effects on tensile modulus showed that the highest intensity of the interaction index is related to the interaction of mixing temperature with mixing time and the lowest is the time and percentage of NBR. Manuscript profile
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