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Some novel alloys, including high-entropy alloys, have gained increasing attention due to their diverse properties and applications. This study aims to investigate the relationship between the magnetic properties and phase transformations of the FeCrCoNiMn high-entropy alloy with the addition of titanium.

The high entropy alloy powder was synthesized by mechanically alloying pure constituent elements in a planetary mill. The synthesized high entropy alloy powder was phase-analyzed using the X-ray diffraction method. Furthermore, phase structure formation was predicted by thermodynamic functions via JMatPro software. The magnetic behavior was analyzed using a vibrating sample magnetometer, and particle morphology was examined using field emission scanning electron microscopy.

The FeCrCoNiMn alloy milled includes a single-phase FCC structure after 40 hours. The presence of Ti in the composition of the alloy created BCC and Laves phase structures. Concurrently, the addition of titanium increased both the coercivity force and saturation magnetization. 

The increase in saturation magnetization is due to the formation of the BCC phase in the FeCrCoNiMnTi alloy, while the BCC phase has a strong exchange interaction between ferromagnetic elements. However, the presence of both the non-magnetic Laves intermetallic phase and interphase boundaries has increased the coercivity force.

This study was conducted to evaluate the adhesion strength and oxidation behavior of SiC/Mo-Si-B coating applied on graphite substrates. For this purpose, SiC coating was created on graphite substrate using pack cementation method with NH4Cl activator. The secondary layer Mo-Si-B coating was created using atmospheric plasma spraying (APS) with argon protective shower on the samples. Surface morphology and chemical composition of the SiC and Mo-Si-B coatings were inve stigated by Scanning Electron Microscopy (SEM) equipped with an Energy Dispersive Spectroscopy (EDS) system. Surface analysis by X-ray diffraction (XRD) revealed that the structure of SiC was mainly composed of SiC phase. In the case of Mo-Si-B, different phases of Mo and Si, Mo and B, and pure Mo were identified. The adhesion of the multi-layer coating was evaluated by tensile test which indicated a sufficient adhesion and cohesion of the coating. The oxidation test was carried out in the air at 1273 K and the time and weight changes were recorded simultaneously. The results showed that the applied coating significantly improves oxidation resistance of graphite with SiO2 and B2O3 glass layers. 

According to the widespread use of aluminum alloys in the oil and gas and petrochemical industries and their low corrosion resistance in corrosive environments, it is necessary to make the surface of these alloys resistant to corrosion using a appropriate coating method. In this research, the coating method in an aqueous environment in an autoclave on the surface of 6061 aluminum alloy was used and its corrosion resistance was investigated. The cleaned samples were placed in an autoclave. Then, by controlling the temperature, time and pressure, an oxide / hydroxide coating was created on the surface. X-ray diffraction (XRD) patterns showed that the coating generally contained an AlO(OH) phase. Scanning electron microscopy (SEM ) images of the coating surface showed that the cubic nanocrystals were densely formed throughout the surface. Vickers microhardness test also showed that the coating was soft and had no effect on the surface hardness. However, the polarization curves show that the corrosion current density of the generated substrates is significantly reduced and the corrosion potential is more positive. As the parameters of autoclave temperature, time and pressure increase, the coating thickness increases and the corrosion current density decreases. It was also concluded that the coating method in the aqueous environment inside the autoclave in liquid and immersed state is a more desirable method due to the higher autoclave pressure than the water vapor state. This indicates that the corrosion resistance of 6061 aluminum alloy has been significantly increased by the use of steam coating.

In this research, ordered porous anodic templates with 30 nm diameter and 15 µm thickness were prepared by using double anodization process. Dip coating method was employed to synthesize strontium ferrite in the form of nanowires in sol dilution. Ferrite nanopowders were also synthesized using sol gel method. The characterization of the nanostructures were examined by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive Spectroscopy (EDS). Hysteresis loops of nanopowders and nanowires, parallel and perpendicular to the wires axes, were measured by Superconducting Quantom Interference Device (SQUID). The results showed that double anodization in 0.3 M oxalic acid at 4 oC with a single anodization for 12 hours could produce ordered template. Dip coating in 80 oC for two hours could form fine and uniform strontium ferrite nanowires. The produced material showed parallel anisotropy.

Organic–inorganic hybrid coatings were prepared by sol–gel method and deposited on aluminum alloy 6061. Attenuated Total Reflectance-Fourier Transform Infrared (ATR-FTIR) spectroscopy and Scanning Electron Microscopy (SEM) were used for structural study of the hybrid coatings. Adhesive strength of sol–gel coatings to the substrate was evaluated quantitatively and qualitatively. Corrosion behavior of the samples was studied by cyclic potentiodynamic and linear polarization tests. Results showed that adhesion strength of the coatings to the substrates was increased with increasing tetrapropoxide of zirconium (TPOZ) and cerium content. Corrosion tests showed that corrosion current density of coated samples were decreased three to seven orders of magnitude in comparison with uncoated aluminum alloy 6061. Decreasing in corrosion current density and increasing in polarization resistance was observed by increasing zirconia and cerium content. Unlike the uncoated aluminum alloy 6061, the crack-free coatings did not show pitting tendency.

In this study, synthesis of silicon nitride by mechanical alloying and the effects of important parameters of milling time and heat treatment temperature, time and rate are presented. Silicon micro powder and nitrogen gas were used as precursor materials. Synthesized phases, morphology and particle size were investigated by X-ray diffraction pattern (XRD) and Field emission scanning electron microscopy (FE-SEM), respectively. X-ray fluorescence analysis (XRF) was used for silicon nitride purity investigation.The optimum sample was produced at 30 h milling time, heat treatment at 1300 ℃ and 22 ℃/min heating rate conditions. X-ray fluorescence analysis showed more than 98% purity.

The aim of this research is evaluation of tribological properties of Ni(5Al)-Al2O3-MoS2 composite coating deposited by atmospheric plasma spray process on the CK45 steel substrate. For this purpose, three powder materials composed of 60wt%Ni(5Al)-40wt%Al2O3, 60wt%Ni(5Al)-35wt%Al2O3-5wt%MoS2 and 60wt%Ni(5Al)-25wt%Al2O3-15wt%MoS2 were prepared by mechanical milling and then spray drying processes. Plasma spray treatment was done by a plasma spray apparatus equipped with a gun of PS50 model. The coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), wear and coefficient of friction tests. In order to study the tribological properties of the coating, wear tests were performed by using a high temperature pin on disk machine. The tests were performed at temperatures of 25, 300 and 6000C, under 5N load and pin rotation speed of 0.1m/s. The wear test results at 25oC showed the presence of brittle phase of NiAl2O4 and lack of MoS2 lubricate in the 60wt%Ni(5Al)40wt%Al2O3 coating led to delamination wear. In this case, coefficient of friction decreased from 0.98 to 0.80. Significant weight loss was not observed during the wear test at 25oC in the coating contains 15wt% lubricant, due to the presence of Ni solid solution and absence of brittle phase of NiAl2O4. Due to the simultaneous presence of NiO and MoO3, 15wt%MoS2 coating showed the best lubricant performance at 600oC, thus, coefficient of friction was reduced from about 0.95 to 0.25.

The purpose of this article of depositing and structural characterization of Ni(5Al)-Al2O3-MoS2 composite coating on the CK45 substrate by atmospheric plasma spray process. For this purpose, Powdering materials by combining the 60%Ni(5Al)-40%Al2O3, 60%Ni(5Al)-35%Al2O3-5%MoS2 and 60%Ni(5Al)-25%Al2O3-5%MoS2(wt%) were prepared by mechanical working mill. The spray dryer process was performed to increase the uniformity of density and granulation of the powder particles. Spraying operation by a plasma spray with gun equipped model PS50 at a distance of 100 mm, a current of 350 A and a voltage of 35 kV was done. The powder and coated surface were characterized by x-ray diffraction (XRD), scanning electron microscopy (SEM), roughness and powder flow tests. Fluidity of powder was investigated by powder flow test according to Agglomerated powder exit from outlet of Hall flow meter. In order to investigate the substrate roughness and the effect of depositing composite coating on the average substrate roughness, roughness test with ultrasonic detector by contact method was performed. The results of the roughness test showed that with the increasing amount of MoS2, average coating roughness was reduced from 5.95 to 4.08 μm. According to the results of XRD, brittle NiAl2O4 phase in the coating without lubricant compared to lubricant coatings the more was formed. Composite powder structure and micrometer interfaces were led to the combination of Ni and S. According to the results can be expressed that depositing of Ni(5Al)-Al2O3-MoS2 composite coating with different amounts of MoS2 lubricant by APS method is possible.

Ni–SiC composite coatings are successfully employed as a protective coating in the inner walls of engine cylinders. In this study, Ni-SiC, Ni-SiC-MoS2 and Ni-SiC-Gr composite coatings were prepared from a sulfamate bath. Both mechanical and ultrasonic stirring were used simultaneously during the process. Taking into account the working temperature of engine cylinders, the wear behavior of coatings was evaluated at 25 to 300 ºC and the high temperature tribological properties of the coatings were investigated. Based on the results obtained from the wear tests, all three coatings showed almost good friction coefficient values at 25 and 100 ºC, which were close to each other. By increasing the temperature to 200-300 °C, the friction coefficient and weight loss values strongly increased. However, addition of solid lubricants caused the values to decrease. The Ni-SiC-Gr coating at all temperatures showed a good and stable behavior.

Silicon nitride has attracted a considerable attention because of its excellent properties such as high-temperature strength، good oxidation resistance، high corrosion resistance، good thermal shock resistance، high creep resistance and good thermal and chemical stability. There are several different fabrication methods for synthesizing Si3N4 particles. Such methods are mostly costly and kinetically slow and require lengthy heat treatment. In this study، Si3N4 compounds were synthesized by means of mechanical milling. In the mechanical milling route،Si powder (≤99. 0%) was milled under nitrogen gas for 25 h and heated at various temperatures 1100-1200-1300 and 1400 C for 1 h at the nitrogen atmosphere at a rate of 200 ml/min. Silicon powder was also annealed under a similar condition in order to evaluate the impact of milling process on the low temperature synthesizing of Si3N4. Phase identification and microstructural characteristics of products were evaluated by X-ray diffraction، scanning electron microscopy and energy dispersive spectroscopy. The Fourier transform infrared spectroscopy and thermal analysis were used for characterization of the formed bands and thermal treatment of the sample، respectively. The obtained results exhibited that Si3N4 powder was fully formed with two kinds of morphologies including globular particles and wire with a width of 100–300 nm and length of several microns at sintering temperature of 1300 C. This was confirmed by the Si–N absorption bonds in the FTIR trace. Based on XRD results، 25 h milling reduced temperature of reaction remarkably in comparison with direct nitridation of Si powders for 1 h. With an increase in the reaction temperature، the Si3N4 samples had a phase transformation α→β، and variation of the morphology followed the vapor–liquid -solid mechanism.

In this study, pure powders such as molybdenum, silicon, aluminum and titanium carbide were utilized to produce MoSi2 compound, MoSi2 /20 Vol % TiC composite, MoSi2-x Al alloyed compound and MoS 2-x Al/20 Vol % TiC alloyed composite. The initial powders were mixed in specified ratios, and then, were activated by mechanical milling. Milled powders were compacted, synthesized and sintered in the temperature range of 1100 -1400 oC. SEM was used to investigate the microstructural change and XRD for identification of phases. Effect of aluminum addition on phase formation was investigated. Addition of aluminum by over 9 atomic percent resulted in the formation of Mo(Si,Al)2 in alloyed matrix.

Mechanical alloying is one of advanced methods in producing alloy and composites materials. In this paper، AA7010 alloy was produced from elemental powders through mechanical alloying under argon atmosphere. Particle size measurements showed The results showed that fine and equiaxed particles with mean particle size of 6μm were formed after 28 h milling. The equiaxed particles observed by SEM after mechanical alloying. X-ray diffraction results for milled powders showed that Al crystallite size reduced to 53nm. Different intermetallic compounds including MgZn2، Mg2Zn11، Al2Cu and Al2CuMg were formed in 24 h mechanically alloyed AA7010 powder after annealing treatment at 550 °C in argon atmosphere. The microharness of mechanically alloyed powders was increased with respect to milling time. Differential scanning calorimetry analysis on AA7010 aluminum alloy also indicated that melting point has reduced to 647 °

In this study, 76Mo-14Si-10B and 30Mo-47Si-23B (at.%) powder compounds were milled for 20 hours using an attritor ball mill with milling speed of 365rpm under inert gas atmosphere. After degasing of As-milled powders at 450℃ temperature for 2 hours, they were pressed into cylindrical samples with 25mm diameter and were sintered at 1100℃-1400℃ temperature range by tube resistance furnace under Ar gas atmosphere. Wear behavior of Mo-Si-B alloys were investigated using a pin-on-disk wear test machine. The results of waer tests under 20N and 30N forces showed that sintered 30Mo-47Si-23B alloy at 1300℃ temperature for 3 hours has more wear resistance than 76Mo-14Si-10B alloy because of MoSi2 and MoB intermetallic particles fine and uniform distribution.

The present research deals with the synthesizing of chromium coating by pulse and direct current from standard bath chromium in the same condition. Crystal structure, morphology, hardness, and surface roughness of fabricated coatings were controlled by varying processing parameter including on time and off time.X-ray diffraction and scanning electron microscopy were employed to evaluate the phase identification and surface morphology of coating. It was found that β-chromium with hexagonal structure forms in pulse plating; however with an increase in off time, the amount of β-chromium in the structure was increased. Finally the coating morphology was affected and varied from trigonal pyramidal like in 50% duty cycle to cubic structure in 20% and caused a decrease in coating properties.

In this study, in order to produce intermetallic compound of MoSi2, pure molybdenum and silicon powders were milled using and attritor mill for 20 hrs with the molar ratio of Mo:Si being equal to 1:2. Mechanically alloyed powders were annealed in an atmosphere controlled furnace at 1100˚C for different times. The result of X-ray diffraction (XRD) and scanning electron microscopy (SEM) indicated formation of pure MoSi2 which was achieved by mechanical alloying for 20 hr followed by annealing for 7hrs at 1100˚C. Since the produced powders were extremely fine and not suitable for thermal spraying, they were agglomerated by carboxymethyl cellulose (CMC) binder and were meshed. This allowed a better flow of the powders and indicated a suitable flow for thermal spraing.

In this study, Mo-14Si-10B and Mo-57Si-10B (at%) elemental powders were separately milled using an attritor mill.Mechanically alloyed powders were agglomerated and annealed. Then, powders of Mo-Si-B as alloyed (with composites) and agglomerated (without composites) were plasma sprayed onto plain carbon steels. The samples, both coated and noncoated,were subjected to isothermal oxidation tests. Metallurgical characteristics of powders and coatings were evaluated by SEM and XRD. Plasma-sprayed Mo-Si-B coatings (with phases of MoSi2, Mo5Si3, MoB and Mo5SiB2) greatly improved the oxidation resistance of the plain steel substrates, but plasma-sprayed Mo-Si-B coatings (without any phases) did notsignificantly improve the oxidation rate of substrates. Also, the kinetics and composition of the oxide-scale have been found to depend on the alloy composition.