In this study, we aimed to modify polymeric membranes by incorporating magnetic nanoparticles (NPs) to enhance their properties. The structural and chemical properties of magnetic NPs of iron oxide were prepared via a wet chemical method. Iron oxide nanoparticles (IONPs) were used as the core and were coated with polymers polyvinyle alcohol (PVA) and polyvinylpyrrolidone (PVP). The prepared samples were cast on a glass substrate using a casting knife. The aim of this study is the use of a specific type of magnetic NPs, coated with a polymer, and their application in membrane modification. We employed a facile synthesis method to coat the IONPs with the polymer and characterized the resulting material using various techniques, including X-ray Diffraction (XRD), scanning electron microscope (SEM), Fourier Transform Infrared (FTIR) Spectroscopy, and UV/Visible (UV–Vis) Spectroscopy for structural, morphological, chemical bonding, and optical properties studies. Our results show that the modified polymeric membranes exhibited improved properties, such as increased permeability and selectivity. We also observed that the magnetic NPs helped in the easy recovery of the modified membranes using an external magnetic field. Some agglomeration of IONPs was also observed, and the polymer membrane caused a decrease in crystallinity of IONPs. Overall, this study presents a promising approach for enhancing the properties of polymeric membranes using magnetic NPs and can potentially have practical applications in various fields, such as water treatment, food processing, and biotechnology.

This paper explores the bioconvective Maxwell fluid flow over a horizontal stretching sheet. The Maxwell fluid flow is considered in the presence of gyrotactic microorganisms. The velocity slips and convection conditions are used in this investigation. Additionally, the Cattaneo–Christov heat and mass flux model, Brownian motion, thermophoresis, and activation energy are employed in the flow problem. The model formulation has been transferred to a dimension-free format using similarity variables and solved by the homotopy analysis approach. Figures have been sketched to depict the HAM convergence. The consequences of this study are that the velocity of Maxwell fluid flow reduces for higher Hartmann number, buoyancy ratio factor, and bioconvective Rayleigh number, whereas the increasing behavior in velocity profile is seen against Deborah number. The thermal characteristics of the Maxwell fluid flow diminish with developing values of the thermal relaxation factor and Prandtl number, while augmenting with the increasing Brownian motion, thermal and concentration Biot numbers and thermophoresis factor. The rate of thermal transmission of the Maxwell fluid flow enhances with the increasing Prandtl number, and mixed convective factor, while diminishing with the increasing buoyancy ratio factor, thermophoresis factor and Brownian motion factor.

In this paper, A356/B₄C composites were fabricated using the friction stir processing (FSP) method. The process’s input parameters, including rotational and transverse speed, were optimized using the response surface methodology (RSM). Three factors and three levels with nine experimental runs made up the design of the experiments. An analysis of variance (ANOVA) was employed to determine whether the constructed model was adequate at a 95% confidence level. This study found that transverse speed was the most critical variable affecting the composites’ silicon (Si) particle size, UTS, and force. The findings demonstrate that the Si particle size of the parent material and the dispersion quality of B₄C particles in the aluminum matrix are considerably influenced by the FSP factors, such as rotating speed and transverse speed. Second, tests for tensile strength were conducted to examine the composites’ mechanical properties. Then, using a specially designed fixture to measure force during the process, the forces on the tool, which play a decisive role in determining the tool’s life, were measured in different input parameters. The findings demonstrate that FSP transforms the mechanism of the fracture from brittle to extremely ductile in composites from the as-received metal.

Hydroxyapatite (HA)-coated metallic substrates are commonly used for load-bearing orthopedic implants. In this work, Titanium grade 2 and Titanium grade 5 substrates were coated with hydroxyapatite and hydroxyapatite reinforced with 5% (by wt.) multiwalled carbon nanotubes (MCNT) separately using plasma spray coating. The wear behavior of these coated substrates was studied with the simulated body fluid (SBF) having a pH between 7.20 and 7.40. Fracture toughness and wear resistance of HA reinforced with 5% (by wt.) MCNT composite coating was found to be higher as compared to pure HA coating. This improvement is by virtue of inherent mechanical properties and the crack bridging effect offered by MCNT. The addition of MCNT also helped in restricting crack propagation in the coatings. As evident from SEM images, abrasive and adhesive wear mechanisms were observed which reduce greatly with the reinforcement of MCNT.

The ternary PtNiCo catalyst grafted by sulfonic group on reduced graphene oxide (RGO–SO₃H) was prepared by a simple solvothermal method. The sheets of nanostructure were stacked in the shape of near-sphere by field-emission scanning electron microscope (FESEM). X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy were carried out to explore the phase structure, element analysis and carbon hybridization, respectively. The ternary PtNiCo alloys were evenly distributed on the supports of RGO–SO₃H with size ranging from tens of nanometer in thickness and hundreds of nanometer in length. The electrocatalysis of PtNiCo/RGO–SO₃H was superior to that of PtNiCo/RGO and PtNiCo/GO catalyst for ORR. The stability of PtNiCo/RGO–SO₃H catalysts was characterized by the electrochemical surface area (ECSA) with 35% loss of the hydrogen adsorption/desorption after repeating 5000 cycles. The –SO₃H groups grafted on RGO were in favor of ORR and anchoring site for PtNiCo nanoparticles. The high lattice contraction will support the retention of Ni and Co to enhance the catalyst activity in the ternary PtNiCo alloy. The synergistic effect of –SO₃H groups and alloying elements can improve the catalytic efficiency and stability of PtNiCo/RGO–SO₃H in the potential application of proton exchange membrane fuel cells.

Pure copper, copper-based alloys, brass, graphite and steel are the most common tool materials for the electrical discharge machining (EDM) process. The electrode material, which exhibits good conductivity to heat and electricity and possesses better mechanical and thermal properties, is preferred for EDM applications. The major problem with conventional electrodes like copper and graphite is their low wear resistance capacity. This study is on the fabrication of Cu–SiC composites as an electrode of EDM with improved wear characteristics for machining of hardened D2 steel which is widely used in die formation. Powder metallurgy route was used to fabricate the samples which was further followed by three-step sintering process. Copper metal was used as a matrix element which was reinforced with SiC in volume fractions of 10%, 15% and 20%. Based on the desirable properties for the EDM tool, the best composition of Cu–SiC composite tool tip was suggested and was further used for machining of D2 steel. The performance of newly developed Cu–SiC composite electrode in terms of surface roughness (SR), material removal rate (MRR) and tool wear rate (TWR) was explored, and it was compared with the pure copper electrode. Pulse on-time, pulse off-time and the input current were selected as the input process parameters. Result reveals that the TWR and SR were decreased by 12–18% and 10–12%, whereas the MRR was increased by 9–28% for Cu–SiC composite tool as compared to the pure Cu electrode. Adequacy of the results was checked by statistical analysis. The surface texture of tool and machined surface was analyzed using scanning electron microscopy (SEM). SEM micrograph revealed that surface cracks on composite tool tip were lesser than pure Cu tool tip, whereas the work surface was rough while machining with the copper tool surface. Therefore, the result indicates that the newly developed Cu–SiC composite tool can be used for machining of hard materials with EDM.

To improve the wear resistance of the titanium alloy, the tungsten inert gas cladding was used in this study. The Stellite6-CeO₂-MnSi-B₄C composite coatings were fabricated on the Ti–6Al–4V (TC4) alloy by the preset-powder cladding process. The scanning electron microscope analysis of the composite coatings showed the effect of the different compositions on the microstructure. The crack propagations could be retarded to some extent due to an action of B₄C. The high-resolution transmission electron microscope revealed the formation of the amorphous phases and the nanocrystals. The formation of amorphous phases could be induced by the lattice distortions. The results of sliding wear tests on the samples showed that the wear resistance of TC4 could be improved due to the synergy effects of the fine grain/dispersion/solid solution strengthening.

Regarding biocompatibility, toxicity, degradation, and interaction with body cells, the materials as well as fabrication process used for biomedical implants are crucial aspects. Implant materials are chosen in accordance with these criteria. The most recent medical implants are made of materials, i.e. stainless steel, Co–Cr and titanium alloys. Although these conventional implant materials generate hazardous ions and have a stress shield effect in many medical implant situations, the implants must be removed from the body within a certain period of time. In order to avoid the need for implant removal, researchers advise using magnesium metal matrix composite (Mg-MMC) as an implant material. Magnesium composites are subjected to a variety of engineering processes to enhance their mechanical and biocompatibility properties, including the addition of reinforcement, treating the surface, and changing the synthesis processes. The solid-state “friction stir process” is discussed for the fabrication of magnesium metal matrix composites. The influence of various reinforcing materials’, process parameters and reinforcing strategies are summarized in this review study with respect to the microstructure, mechanical characteristics, and corrosion behavior of biodegradable magnesium matrix composites. This study provides an importance of magnesium-based composites for biomedical implants and the degradation behavior reduces the secondary activities to remove implants.

Laser cladding (LC) is mostly employed to enhance the wear resistance of magnesium alloy substrates. Adding nanoparticles will further strengthen the tribo surface properties, making them suitable for applications requiring lightweight components. This work investigated a dry sliding wear analysis for the laser-cladded AZ61 magnesium alloy with TiO₂ nanoparticles at different volume ratios through the LC method. The spatial dispersion of the TiO₂ nanoparticles in the AZ61 magnesium alloy microstructure was analyzed using scanning electron microscopy (SEM). The reinforcement ratio, sliding speed, and normal load were selected to study the tribo performance of the cladded surface. Coefficient of friction (COF) and wear loss analyses were performed using a pin on the disc dry sliding wear test. The effect of dry sliding variables on reinforcement ratio was analyzed with an orthogonal array experimental design. Grey relational analysis (GRA) studied multiple wear test responses to reveal optimal conditions to decrease the wear and friction coefficient of the AZ61 laser cladded surface. The reinforcement percentage of nanoceramic TiO₂ particles in the AZ61 alloy surface was the most significant factor, contributing 97.76%, followed by a contribution of 0.26% by sliding speed and a normal load of 1.82%, confirmed with the grey relational grade. Both SEM and GRA confirmed that the reinforcement ratio of 10% exhibited lower wear loss and friction coefficient. The revealed wear mechanism operating on the worn surface of laser-cladded AZ61 magnesium alloy was micro-grooving exerted by a counter surface at all sliding conditions. This study shows that the LC of magnesium alloys will be preferred in sliding seal and lightweight gear applications.