Iranian Journal of Materials Science and Engineering

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Abstract:

as magnetic materials, semiconductors, pigments, catalysts, refractories and electronic ceramics. In this paper, we

reported the preparation of NiAl

The resulting powder was chracterized by XRD, particle size analysis and SEM. The XRD patterns show that the

combustion technique was excellent to prepare single – phased cubic NiAl

found to be around 14 nm. From the particle size analysis, it was found that the 50 % of the particles lie below 30

µm. The micrographs show the formation of fluffy agglomerates composed of fine particles.

Spinels constitute an advanced group of materials with great technologial appeal, being able to be applied2O4 spinels by low temperature combustion technique using glycine and urea as fuels.2O4 particles and the crystallite sizes were

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Electrochemical coating processes are significantly affected by applied magnetic fields due to the generation of electromagnetic forces. The present research work has been undertaken to study the effect of coating parameters such as current density and alumina concentration on the characteristics of Ni-Al2O3 composite coating under static magnetic field. Ni-Al2O3 composite coating was applied on a mild steel substrate using conventional Watts solution containing Al2O3 particles with and without magnetic field. The coating microstructure and Al2O3 particle density in the coating layer were examined by scanning electron microscopy (SEM). It was found that the applied magnetic field made the coating structure finer and leads to the increases of the particle content in the coating. However, the results confirmed that the magnetic forces inversely affected the particle density in the coating at higher current density than that of normal coating process.

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B4C and its composites with TiB2 as second phase continues to be extensively used as the preferred ceramic material in military applications as armor systems for absorbing and dissipating kinetic energy from high velocity projectiles. It also exhibits a high melting point (2427 °C), and high neutron absorption cross section. Pressureless sintering of the B 4C-nanoTiB2 nanocomposite using small amount of Fe and Ni (≤3 Wt%) as sintering aids was investigated in order to clarify the role of Fe and Ni additions on the mechanical and microstructural properties of B4C-nanoTiB2 nanocomposites. Different amount of Fe and Ni, mainly 1 to 3 Wt% were added to the base material. Pressureless sintering was conducted at 2175, 2225 and 2300 °C. It was found that Addition of 3 Wt% Fe and 3 wt% Ni and sintering at 2300 °C resulted in improving the density of the samples to about 99% of theoretical density. The nanocomposite samples exhibited high density, hardness, and microstructural uniformity.

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Ceramic-matrix composites containing TiC-TiN have been used in a variety of application because of their superior properties such as high hardness, good wear resistance and high chemical stability. In this research, effect of coke and coke/calcium beds in synthesis of Al 2O3-Ti(C, N) composites using alumino-carbothermic reduction of TiO 2 has been investigated. Al, TiO 2 and active carbon with additives of extra carbon and NaCl and without additives, in separate procedures, have been mixed. Afterwards, mixtures were pressed and synthesized in 1200oC for 4hrs, in coke and coke/calcium beds, separately. Al 2O3-Ti(C,N) composite was synthesized in ternary system of Al-TiO 2 -C with excess carbon and NaCl additives in calcium/coke bed in 1200 . X-ray diffraction patterns (XRD) results showed that existence of calcium in bed resulted in intensification of reduction atmosphere in samples and formation of Ti(C,N) phase enriched from carbon was accelerated. Crystallite sizes of synthesis Ti(C,N) at 1200 °C in reducing conditions were 22-28 nm.

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The evolution of microstructure and mechanical properties of a magnesium cast alloy (AZ31) processed by equal channel angular pressing (ECAP) at two different temperatures were investigated. The as-cast alloy with an average grain size of 360  was significantly refined to about 5  after four ECAP passes at 543 K. Grain refinement was achieved through dynamic recrystallization (DRX) during the ECAP process in which the formation of necklace-type structure and bulging of original grain boundaries would be the main mechanisms. ECAP processing at lower temperature resulted in finer recrystallized grains and also a more homogenous microstructure. The mechanical behavior was investigated at room temperature by tensile tests. The obtained results showed that the ECAP processing can basically improve both strength and ductility of the cast alloy. However, the lower working temperature led to higher yield and ultimate strength of the alloy.

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The Nano Hydroxyapatite (HAp), HAp/PEG and HAp/PVP powders derived from both Gastropod shell (natural source) and chemical precursor by the precipitation method were characterized through various characterization techniques such as FT-IR, XRD, SEM-EDX, TEM, Antibacterial activity and SBF analysis. Based on the structural, chemical, morphological and biological characteristics, HAp/PVP from natural and chemical precursors have been compared successfully. Calculated structural parameters, crystallinity index, C/P ratio, morphology, antibacterial activity and SBF analysis of the products show that HAp/PVP-S (derived from a natural source) exhibits good mechanical property, rod like morphology, good antibacterial activity and apatite formation ability at 14 days. EDX analysis also shows the presence of carbon and sodium in HAp/PVP-S. Comparative analysis reveals that characteristics of HAp/PVP-S such as high carbonate content, low crystallite size, poor crystalline nature, presence of trace metal, non-stoichiometric elemental composition and rod like crystals which are matched with the characteristics of biological apatite. Thus, the HAp/PVP-S has the ability to form bone apatite.

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The low velocity impact (LVI) response of pure and glass fiber reinforced polymer composites (GFRP) with 0.1, 0.3 and 0.5 wt% of functionalized single-walled carbon nanotubes (SWCNTs) was experimentally investigated. LS-DYNA simulation was used to model the impact test of pure and incorporated GFRP with 0.3 wt% of SWCNT in order to compare experimental and numerical results of LVI tests. All tests were performed in two different levels of energy. In 30J energy, the specimen containing 0.5 wt% SWCNT was completely destructed. The results showed that the incorporated GFRP with 0.3 wt% SWCNT has the highest energy absorption and the back-face damage area of this sample was smaller than other specimens. TEM images from specimens were also analyzed and showed the incorporation of well-dispersed 0.1 and 0.3 wt% of SWCNT, while in specimens containing 0.5 wt% of CNT, tubes tended to be agglomerated which caused a drop in LVI response of the specimen. The contact time of impactor in numerical and experimental results was approximately equal; however, the maximum contact forces in LS DYNA simulation results were higher than the experimental results which could be due to the fact that in the numerical modeling, properties are considered ideal, unlike in experimental conditions.

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In this research, expanded graphite (EG) was successfully fabricated using a simple ball milling process followed by hydrofluoric (HF, 10 wt. %) leaching. The effects of ball milling time (0-15 h) and leaching time (1-24 h) on the exfoliation of graphite were examined by XRD and Raman spectra. Furthermore, the morphological evaluation of the obtained expanded graphite samples was carried out by scanning electron microscopy (SEM). The XRD results of the ball-milled and HF treated samples showed a slight peak shift and broadening of (002) plane for expanded graphite compared to the precursor and HF-treated samples. Moreover, the intensity of the (002) planes remarkably decreased by the ball milling process but remained constant after HF treatment. Raman spectra of the samples confirmed the ordering process only in HF-treated specimens. Moreover, the intensity ratio of 2D₁ to 2D₂ band gradually increased with enhancing the HF treatment time up to 5 hours, indicating a decrement in the number of graphite layers by leaching in the HF solution.

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In this study, CrN/ZrN multilayer nanostructured coatings with different bilayers (10, 20, and 30) were created by the cathodic arc evaporation. The electrochemical behavior of samples was evaluated by polarization and impedance spectroscopy tests in the Ringer medium and the pin on disk test was used to investigate the tribological behavior of the samples. The results of measurements showed that the electrochemical and tribological behavior of the coatings depends on the number of bilayers and by rising the number of bilayers, the coating shows higher corrosion resistance and better tribological performance. Field emission scanning electron microscopy (FE-SEM) images of the specimens after exposure to the corrosion medium showed that the number of surface cavities were formed by the coating that had the highest number of bilayers comparing with other coatings were quite fewer in number and smaller in diameter. The results of the pin on disk test showed that by increasing the number of bilayers from 10 to 30, the coefficient of friction and wear rate decreased and the 30L coating ‌showed better wear resistance.

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Hybrid composite finds wide application in various fields. In this present study, the hybrid composites are developed using stir casting technique as per Taguchi’s L9 orthogonal array. Hybrid composites were fabricated using Aluminium Al6082 as the base material and reinforced with the combinations of reinforcements Al2SiO5 and B4C at three levels (4%, 8% and 12%).The developed composites were analyzed for micro structural  investigations and mechanical tests were done as per ASTM standards. The micro structural analysis was done using optical Microscope and Scanning electron microscope while composition studies were done using X-ray diffraction and EDAX. Mechanical test like tensile, impact and flexural were conducted and their damage assessment was done using Scanning electron microscope. The fatigue characteristics like high cycle fatigue and fatigue crack propagation was studied both experimentally and numerically. The experimental data and numerical modeling analysis data obtained for the hybrid composite system, agree with each other.           

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Single crystals of double crystalline block copolymers of poly(ethylene glycol) (PEG)-b-poly(ε-caprolactone) (PCL) and PEG-b-poly(L-lactide) (PLLA) were grown from dilute solution in homo- and mixed-brush systems. Crystallization behavior of biodegradable one end-restricted crystallizable PCL and PLLA chains in homo- and mixed-brush nanostructures were investigated. Chemical and physical circumstances of crystallizable brushes were altered. Physical environment was adjusted by amorphism/crystallinity and rigidity/flexibility of neighboring brushes. Chemical environment was manipulated by interaction and miscibility of various brushes. Distinct single crystals were grown with mixed-brushes of amorphous-crystalline (polystyrene (PS), poly(methyl methacrylate) (PMMA), PCL and PLLA, double crystalline (PCL/PLLA), and rod-crystalline polyaniline (PANI)/PCL or PLLA. Surrounding was only effective on hindrance or nucleation commencement of crystallization for crystallizable brushes and had no effect on crystallization features. Novel three-layer fully single crystalline nanostructures, whose characteristics were fixed via changing the crystallization temperature, were also developed. For long crystallizable tethers, crystallization increased both brush and substrate thicknesses. 

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Abstract
In this research, Gelatine (GEL)/ Chitosan (CH) wound dressing was prepared and irradiated with gamma rays from ⁶⁰Co source for wound healing applications. GEL-CH composite characterization and functional properties were determined. The structural changes occurring after γ-irradiation at doses from 5 to 25 kGy were reported by physico-chemical techniques such as Electron Paramagnetic Resonance (EPR), Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Electrochemical Impedance Spectroscopy (EIS) studies. The antioxidant capacity was studied using DPPH (1,1-diphenyl-2-picrylhydrazyl free radical) scavenging and the antibacterial activities of Staphylococcus aureus and Escherichia coli were observed using liquid medium. Results revealed that EPR spectroscopy of un-irradiated GEL-CH showed 2 paramagnetic centers correspond to g=2.077 and g= 2.079. After irradiation, no active centre was appeared. A dose-dependent decrease in the central signal intensity was detected, then the EPR signal intensity almost disappears at 20 kGy. Gamma rays caused a slight increase in ion conductivity. FTIR suggest a slightly crosslinking phenomenon at 20 kGy. The XRD analysis does not show peak indicating crystallinity between a range of 2θ (15–30°). Moreover, γ-irradiation elevated the Scavenging DPPH radical activity (0.75 ± 0.07%). Gamma rays did not affect the antibacterial activity of GEL-CH wound dressing against pathogenic bacteria. The innovative results showed that the required γ-radiation for sterilization was ranged from 5 to 25 kGy. It permits to improve the physico-chemical and biological properties and maintain the native structural integrity of the GEL/ COL wound dressing

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Abstract
Gelatin (GEL) is most extensively used in various fields, particularly in therapeutics and pharmaceuticals. GEL was extracted from goat skin using hot temperature extraction process and compared with that of commercial GEL. The physico-chemical characterization and functional properties were investigated by using temperature denaturation (T_d), water-holding and fat-binding capacities (WHC and FBC), colour measurement and UV-light spectrum. In vitro biocompatibility was studied for the first time and was evaluated by blood coagulation index (BCI) and haemolytic tests for using as wounds dressing. The results revealed thermal stability of goat GEL at T_d 37°C. WHC and FBC capacities represented 2.5 and 1.2 g/ml, respectively. The hunter colour spaces a*, b* and L* showed a -0.27, -1.97 and 25.23 values, respectively. UV-Vis absorption spectrum of the goat GEL showed a maximum absorption peak at 280 nm. The in vitro anticoagulant activities of extracting GEL were higher than 70% after incubation for one hour. After being in contact with red blood cells for 1 h, the haemolysis ratio increased from to 0.46 to 1.4 when the concentration of goat GEL increased from 1 to 50 mg/ml suggesting the safety of the tested samples. These results suggest that thromboresistivity and hemocompatibility of this biopolymer retained the biological activity of our samples for biomaterial applications. According to this, goat GEL successfully competes with, and significantly could be useful for substitution of bovine in wound healing.

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In this study, for the first time, the Forsterite (Mg₂SiO₄) nanoparticles (NPs) with the size of about 25 nm were added to the phosphate-based electrolyte, and the characteristics and properties of the obtained plasma electrolytic oxidation (PEO) coating on AZ31 Mg alloy was investigated. The results of the potentiodynamic polarization measurements revealed that after one week of exposure to simulated body fluid (SBF) solution, the coating with Mg₂SiO₄ NPs possessed 12.30 kΩ cm² polarization resistance, which was more than two times greater than that of the coating without NPs. The thicker coating layer, lower wettability, and also presence of Mg₂SiO₄ NPs inside the pores were responsible for enhanced corrosion protection in the Mg₂SiO₄ NPs incorporated coating. After three weeks of immersion in SBF solution, the in-vitro bioactivity test results indicated the ability of the NPs-containing coating to form apatite (Ca/P ratio of 0.92) was weaker than the coating without NPs (Ca/P ratio of 1.17). This could be attributed to the lower wettability of the coating with NPs and supports that the addition of the nanoparticles is not beneficial to the bioactivity performance of the coating. 

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     Zinc Oxide (ZnO) nanorods and titanium dioxide (TiO₂) nanostructures thin films were prepared onto glass substrates by the chemical bath deposition (CBD) method. The ZnO was structured as nanorods (NRs) while TiO₂ was formed as nanoflowers plate as confirmed by Field-Emission Scanning Electron Microscope (FESEM) images. The ZnO/Fe₃O₄ and TiO₂/Fe₃O₄ nanostructures thin films were prepared via drop-casting Fe₃O₄ NPs onto the grown ZnO and TiO₂ nanostructures thin films. The diameter of Fe₃O₄ NPs was deposited onto ZnO NRs thin films and TiO₂ nanostructures thin films was ranged from 8nm to 59nm with dominated range between 10nm to 30 nm.  The crystalline structure of prepared samples was investigated through X-ray diffraction (XRD) method. However, the particles size of Fe₃O₄  was estimated  by XRD as well as FESEM images was around 22 nm. The photocatalytic activity of the as-prepared ZnO/Fe₃O₄ and TiO₂/Fe₃O₄ nanostructures thin films was investigated against methylene blue (MB) dye at room temperature with a pH value of 10 under different exposure time by visible light. The photodegradation rate of MB dye by ZnO/Fe₃O₄ and TiO₂/Fe₃O₄ nanostructures thin films was higher than that obtained by ZnO and TiO₂ nanostructures thin films. The best photodegradation rate of MB dye was 100% after exposure time of 180 min was obtained by ZnO/Fe₃O₄ nanostructures thin film whereas it was 82% for TiO₂/Fe₃O₄ nanostructures thin films after exposure time of  240 min.  
 

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This paper aims to study the tribological and electrochemical properties of the CrN/AlCrN nano-layer deposited on H13 tool steel. Arc physical technique was employed to deposit multilayer coating. X-ray diffraction technique, thermionic and field emission scanning electron microscopy and energy dispersive spectroscopy have been used to determine the characteristics of the samples. To study the samples' wear behavior, coating adhesion, and surface hardness, reciprocating wear test, Rockwell-C test, and microhardness Vickers tester were employed, respectively. The measured values of the coefficient of friction and the calculated wear rates showed that the CrN/AlCrN multilayer coating has a much higher wear resistance than the uncoated sample. The coefficient of the friction of the coated sample was 0.53 and that of the uncoated sample was 0.78. Moreover, the wear rate of the coated H13 steel was about 127 times lower than the bare H13 steel sample. The results obtained from electrochemical impedance spectroscopy and polarization tests demonstrated that the corrosion current density of the H13 steel sample was 8 μA/cm2 and that of the CrN/AlCrN multilayer-coated sample was 3 μA/cm2. In addition, the polarization resistance of the treated and the substrate specimens was estimated at 4.2 and 2.7 kΩ.cm2, respectively.

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As a major global cause of liver disease, non-alcoholic fatty liver disease (NAFLD) is characterized by excessive hepatocellular accumulation of lipids in the liver, elevated levels of hepatic enzymes, and fibrotic evidence. The primary therapies for NAFLD are changing lifestyle or managing comorbid-associated diseases. Lately, nanotechnology has revolutionized the art of nanostructure synthesis for disease imaging, diagnosis, and treatment. Loading drugs into nanocarriers has been established as a promising strategy to extend their circulating time, particularly in treating NAFLD. In addition, considering a master modulator of adipogenesis and lysosomal biogenesis and function, designing novel nanostructures for biomedical applications requires using biodegradable materials. Various nanostructures, including inorganic nanoparticles (NPs), organic-based NPs, metallic nanocarriers, biodegradable polymeric nanocarriers, polymer-hybrid nanocarriers, and lipid-based nanocarriers have been designed for NAFLD treatment, which significantly affected serum glucose/lipid levels and liver function indices. NPs modified with polymers, bimetallic NPs, and superparamagnetic NPs have been used to design sensitive nanosensors to measure NAFLD-related biomarkers. However, certain limitations are associated with their use as diagnostic agents. The purpose of this review article is to shed light on the recent advancements in the field of nanomedicine for the early diagnosis, treatment, and prognosis of this progressive liver disease.
 

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Considering the widespread use of aluminum composites in various industries and the emergence of nanomaterials such as graphene and boron nitrite (BN) with their unique properties, aluminum-based nanocomposite reinforced by the graphene-BN hybrid was fabricated at different percentages. For this purpose, the graphene-BN hybrid was prepared and subjected to wet milling along with the aluminum powder. The mechanical properties of the final nanocomposite which was consolidated using the spark plasma sintering (SPS) method were examined. Aluminum-based composite specimens containing 1 wt.% graphene–0 wt.% BN (AGB1), 0.95 wt.% graphene–0.05 wt.% BN (AGB2), 0.90 wt.% graphene–0.1 wt.% BN (AGB3), and 0.85 wt.% graphene–0.15 wt.% BN (AGB4) were fabricated and compared with non-reinforced aluminum (AGB0). The hardness values of 48.1, 51.1, 56.2, 54.1, and 43.6 Hv were obtained for AGB0, AGB1, AGB2, AGB3, and AGB4, respectively. Additionally, tensile strengths of these specimens were 67.2, 102.1, 129.5, 123.7, and 114.7 MPa, respectively. According to the results of the hardness and tensile tests, it was revealed that the AGB2 specimen had the highest tensile strength (93% higher than AGB0 and 27% higher than AGB1) and hardness (17% higher than AGB0 and 10% higher than AGB1).