Journal of Molecular and Engineering Materials

In the last decade, there has been immense growth in research activities related to tribology. Tribology can have a big impact on the needs of industries to reduce losses and waste by developing new tribological components and materials. Hence, there is a strong connection between tribology and the fourth industrial revolution, i.e., industry 4.0. Tribology is a multidisciplinary field, and the results of research in the field of tribology are widely spread among various disciplines. This review paper briefs the recent advances in various research areas in tribology covering surface engineering, wear and lubrication. The main objective of this review is to summarize the new aspects in the field of tribology, like the numerical techniques of lubrication to model new lubrication schemes, solid superlubricity, superlubricity at the microscopic scale, superlubricity with coating and new 2D materials. The direction for future research in the field has been highlighted. The paper will be beneficial for researchers working in the field of tribology.

Mangifera indica (MIn, commonly known as “mango”), is a most widely cultivated flowering plant species in the family Anacardiaceae capable of growing to a height of 30 meters (100 feet). Being rich in nutritional value and phytochemical constituents, it is known for its tremendous chemical and biological actions. As a contribution to the current interest in green corrosion inhibitors, this review aims at broadening the application of MIn extracts for metallic corrosion inhibition by investigating the inhibiting properties of MIn on various metals of day-to-day importance. The adsorption isotherm studies, chemical composition of MIn, effect of temperature on inhibition efficiency and computational analysis related to MIL adsorption on metals have also been discussed in detail. This work will further help in the understanding of the adsorption mechanism involved. The overarching objective is to provide researchers with a concise but comprehensive knowledge base of MIn as a green corrosion inhibitor.

In this study, we suggest an eccentricity-based linear regression model to predict the effectiveness of anti-Alzheimer’s drugs such as Tacrine, Donepezil, Rivastigmine, Butein, Licochalcone-A and Flavokawain-A. The relationship between structural characteristics and therapeutic effectiveness by integrating eccentricity values is derived from these drugs. Our findings provide promising insights into the potential use of eccentricity-driven linear regression as a drug discovery tool in the field of Alzheimer’s disease treatment. This method provides an improved comprehension of the structural factors influencing drug efficacy, establishing the way for more targeted and efficient anti-Alzheimer’s drug development. Moreover, a quantitative structure–property relationship model is developed by using linear regression model to predict properties such as boiling point, flash point, molar volume, molecular weight, complexity and polarizability.

To determine the optimal dispersion conditions of graphene flakes for ink, its heat dissipation properties were investigated by changing the particle size, dispersant, and binder types. In the case of particle size, the smaller the size of the graphene flakes, the better the dispersion, and regardless of the amount of dispersant and the type of binder, the greatest dispersion effect was exhibited by the mixed dispersant. Under these conditions, internal cohesion did not occur as in Newtonian flow over time, and for this reason, heat was released quickly, with a rapid cooling rate. It is clear that this process of determining the optimal dispersion conditions considering multiple factors will provide a good reference for determining dispersion conditions for various variables in the future.

Reduced graphene oxide (rGO)/TiO₂ nanocomposites were prepared by low-temperature and low-pressure heat treatment. The structure and photocatalysis performance of the composites were characterized by transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), and UV-visible diffuse reflectance spectrum (UV-Vis DRS). The photocatalytic degradation performance of methyl orange (MO) by composites with different raw material ratios was studied under simulated solar-irradiation conditions. Results indicated that graphene oxide (GO) was reduced to graphene during heat treatment and bonded well with TiO₂. Compared with TiO₂, GO addition greatly improved its photocatalytic efficiency. Under simulated sunlight irradiation, the samples exhibited good photocatalysis performance. Within 50min, MO can be rapidly degraded by TiO₂/40% rGO composite.

This study investigates the installation and operation of an automated electrophoretic deposition (EPD) unit for applying Ca coatings on aluminum alloy parts, with a focus on optimizing electrode distance and deposition parameters. The dynamic adjustment of the anode–cathode distance during the process was crucial in influencing the uniformity and adhesion of the Ca coating. The electrolyte solution consisted of 50% acetone, 50% distilled water and 5g/500ml of pure Ca. The average thickness of the Ca coating was approximately 180 microns. Immersion corrosion tests revealed that after a 48h period, the coated sample lost 0.5g of weight, while the uncoated sample lost 1.1g. These findings demonstrate that the thickness and uniformity of the Ca coating significantly influence its protective properties. In conclusion, this study provides valuable insights into the optimization of EPD parameters and the role of Ca coatings in enhancing corrosion resistance in industrial applications.

Utilizing the sol–gel technique, we deposited 5% Mo-doped MAPbI₂Br films onto fluorine-doped tin oxide (FTO)-glass substrates. X-ray diffraction (XRD) analysis confirmed the cubic structure of all films, with the 5% Mo-doped film exhibiting a notably large grain size of 32.34nm. UV–visible spectroscopy further validated these findings, indicating a reduced band-gap energy of 1.94eV and a heightened refractive index of 2.64 and an extinction coefficient of 2.21 in the 5% Mo-doped film. The manipulation of the conduction and valence band edges facilitated enhanced charge transport between the layers. In order to increase the current density, a layer of SnO₂ has been added near the electron transport layer (ETL). XRD and Raman spectra show the formation of crystalline SnO₂. The absorption spectra show the high transmittance in the visible region, which is good for ETL. Solar cells based on these films were constructed with the configuration glass FTO/TiO₂/SnO₂/Mo-MAPbI₂Br/spiro-OMeTAD/Au. The bilayer composed of 5% Mo-MAPbI₂Br and a SnO₂ layer demonstrated excellent performance, characterized by a current density of 11.88mA/cm², an open circuit voltage of 1.07V, a fill-factor of 0.83, and an efficiency of 10.03%. The improvement in performance may be credited to the increased speed of electron transport and decreased likelihood of recombination at the interface between TiO₂, SnO₂, and perovskite layers in the bilayer structure.

This experimental work presents a study of parametric effects during pattern generation under the reverse EDM process. A user-defined pattern is created on aluminum (Al) 6061 surface. The particles are deposited to the work surface using a green compact powder metallurgy (PM) tool. The deposition process is carried out by transferring tungsten (W) and copper (Cu) particles at the chosen region on the Al-6061 surface. The influence of pulse on-time (T${}_{\mathrm{\text{on}}})$ is observed on the output responses i.e., TWR, MDR, Ra and ED of the generated pattern. The experimental results show the significant effects of T_on on the output parameters. A multi-objective optimization is carried out using nondominated sorting based on the Pareto front followed by evaluating the fitness to identify the optimal output combination corresponding to the input parameters. All output parameters are assigned equal weightage. Several output combinations are evaluated, yielding an optimal T_on of 1000 $\mu$s for combinations such as ‘MDR and Ra’, ‘MDR and ED’, ‘TWR and Ra’, ‘TWR, MDR and ED’, ‘TWR, MDR and Ra’ and ‘TWR, MDR, Ra and ED’. Conversely, an optimal T_on of 21 $\mu$s is identified for the combination ‘TWR, Ra and ED,’ while a T_on of 100 $\mu$s is determined as optimal for the combination ‘TWR and ED’. At T_on of 1000 $\mu$s, TWR of 538.1mg/min, MDR of 159mg/min, Ra of 5.2 $\mu$m and ED of 76.89 $\mu$m is obtained. Similarly, at T_on of 21 $\mu$s, TWR of 130.2mg/min, MDR of 19.4mg/min, Ra of 4.30 $\mu$m and ED of 29.35 $\mu$m is obtained. At T_on of 100 $\mu$s, TWR of 328.2mg/min, MDR of 42.9mg/min, Ra of 5.20 $\mu$m and ED of 37.83 $\mu$m is obtained. The surface topography is displayed by FESEM and EDS investigations, which also validate the material transfer to the work surface.

The hydrothermal method has been successfully employed to grow flower garland-like morphologies of sheet and rod-assembled Fe₂O₃ on a carbon thread (CT), utilizing Fe${}^{3+}$ solution as a precursor. The produced materials underwent characterization through scanning electron microscopy (SEM), X-ray diffraction (XRD) and energy-dispersive X-ray spectroscopy (EDS). Subsequently, these Fe₂O₃ garlands were utilized in the construction of gas sensors, which were then tested with various common gases. Operating at room temperature, the sensors exhibited an optimal response value of 50–100ppm acetone. Notably, the Fe₂O₃ garland sensors demonstrated remarkably rapid response and recovery times, measured at 9s and 12s, respectively. The three-dimensional (3D) porous structure and high surface area were identified as crucial components of the underlying sensing mechanism.

AISI 603 steel is a low-carbon, nickel–chromium–molybdenum alloy commonly used in various industrial applications, including the automotive, aerospace, heavy machinery, oil and gas, defense and power generation industries, due to its high strength, toughness, wear resistance and heat treatability. These mechanical properties can be further enhanced by the addition of microalloying elements such as niobium (Nb) and vanadium (V). Although AISI 603 steel is typically produced by casting, the powder metallurgy (PM) method offers several advantages over traditional production techniques. In this study, AISI 603 steel was produced using PM and reinforced with Nb, V and an Nb–V combination. The microstructure, phase composition, corrosion behavior, density and hardness of the samples were analyzed. Additionally, tensile and wear tests were conducted at room temperature and $350^{\circ }$C. The results indicated that the addition of Nb positively impacted hardness and wear resistance compared to V, although it led to a more pronounced deterioration in corrosion resistance. The Nb–V-reinforced sample exhibited the highest tensile strength.