Journal of Environmental Friendly Materials
Volume:8 Issue: 2, Summer-Autumn 2024

The purpose of this research is to investigate the corrosion resistance of Inconel 625 alloy produced by selective laser melting after heat treatment and surface treatment. For this purpose, the samples produced with the help of a Selective Laser Melting Machine (SLM) were prepared in four modes of the prototype (without further treatment), heat treated, surface treated, and finally heat treatment and consecutive surface treatment. To perform heat treatment, the combined cycle of annealing and aging was used. In the surface treatment, the shot pinning method was used for 30 minutes using steel balls. X-ray diffraction analysis was performed to determine the phase of the samples. Peaks of the primary γphase, nickel carbide, and molybdenum were revealed in the heat-treated samples. In the following, the samples were electrochemically evaluated in 3.5 wt.% NaCl medium with potentiodynamic polarization tests and Electrochemical Impedance Spectroscopy (EIS). The results showed that the SLM-HT sample has the most positive corrosion potential and the lowest corrosion current density, while the SLM 625 sample shows the most negative corrosion potential and the highest corrosion current density. Heat treatment improved both thermodynamic behavior and kinetic behavior, but the surface treatment had little effect on improving corrosion. Also, the results of the EIS test showed that the HT-625 sample had the highest polarization resistance and the lowest charge accumulation (capacitance),while the 625 sample showed the lowest charge transfer/polarization resistance and the highest capacitance.

This study investigated the structural and morphological properties of Cu-doped SnO2 films grown on glass and FTO (fluorine tin oxide) substrates by RF magnetron sputtering and annealed at a temperature of 600 ºC. The techniques of X-ray diffraction (XRD), atomic force microscopy (AFM), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDX) were employed to characterize the structural and morphological properties of the films. The XRD results verified the formation of a polycrystalline SnO2 in a tetragonal structure for all samples. The sample deposited on the FTO exhibited a larger crystallite size compared to the sample deposited on a glass substrate. AFM and FESEM images exhibit that the type of the substrates influences the morphology, roughness, and grain sizes of the films. The EDX analysis confirmed the presence of Sn, O, and Cu elements in the films. The results show that the choice of substrate can significantly impact the structural and morphological characteristics of deposited films, influencing their potential applications in various fields such as solar cells and gas sensors.

The cast nickel-base MAR-M247 superalloy has been widely used for high-temperature components. In this work, the creep and room temperature tensile behavior of MAR-M247 superalloy after dual-stage standard heat treatment is evaluated. The microstructure of heat-treated superalloy consists of a matrix with a -eutectic, strengthening cubic precipitates, and particulate, script-like carbides at the grain boundaries (GBs). Under the creep testing conditions in this study, the volume fraction and primary gamma prime size increased; the script-like MC carbide along the GB elongated, and the TCP phase formed in the vicinity of grain boundary carbides. On the other hand, during the creep test, the thin film formed around the gamma prime phase became thicker, causing an increase in the toughness of the superalloy and an expansion of the steady-state stage in the creep curve.

Simulation is one of the methods of interest in various industries, including automobile manufacturing, to reduce the costs, material wastage, and increase the productivity. Simulation has an effective role in reducing process costs and as a result can lead to an increase in productivity in part manufacturing processes. Also, the simulation reduces the environmental pollution caused by the prototypes. In the meantime, it is important to pay attention to the simulation of casting processes, and in the current research, a car engine tappet part is made using analysis simulation and a real sample. The results show that the simulation has played an effective role in identifying possible defects and making a healthy part, and also in the real sample, the presence of carbide and ledeburite structures has been a factor in increasing the hardness of the part. Finally, the increase in hardness may increase the wear resistance of this part, which plays an effective role in the performance of the car engine.

A nanocomposite coating including titanium oxide nanotube and CuO is synthesized on the commercially pure titanium using electrochemical anodizing at 30V for 2 hours in an electrolyte containing Ethylene glycol, water and ammonium fluoride in combination with a magnetron spattering process to produce a thin layer of copper. A thin layer of copper deposited on the titanium prior to anodizing as well as after the anodizing process and then the samples were thermally oxidized under pure oxygen atmosphere at 300°C for 1 hour. Microstructural evaluations revealed that titanium nanotubes were formed over the metallic surface. In the case of the pre-coated sample, CuO particles were detected over and in the nanotubes and for the post-coated sample, a contiguous layer of copper oxide was formed over the nanotubes. Wettability of the produced samples improved in comparison with the sample without copper. Also, the antibacterial activity of the copper-containing samples was better than the raw materials and the sample without copper.

In this Article, laser-based additive manufacturing (AM) of Ni-based superalloys has been evaluated. By reviewing past research and recognizing the challenges and benefits of additive manufacturing, the future of this path can be well described. For this purpose, it is very important and useful to know the target industries, the resulting microstructure, the relationship between the microstructure and the mechanical properties of the final part. In addition, the ways to prevent possible defects of this process are summarized in the report. This report tries to introduce this process in the direction of less damage to the environment and available resources. To be introduced as an environmentally friendly method for manufacturing parts needed for energy supply and transmission. In the future, more reports of this process will be provided by the authors of this review article.

Nowadays, quantum science plays an important role in the development of various applications and systems one of the main ones being quantum lasers. InAs and Ge/GeAs material systems are among those that are of interest in the development of Quantum Cascade Lasers. Also, laser pointers based on quantum lasers are of interest and the development of quantum dot laser diodes is also discussed and developed. Due to the importance of this issue, in this research, in the form of a mini-review, the general aspects of quantum lasers and the latest advancements have been examined and analyzed. It is worth mentioning that lasers play an effective role in the development of various quantum dots, including carbon quantum dots. The purpose of this research is to summarize the latest research in the field of quantum lasers and also to review some of their applications in the development of various types of quantum dots, especially carbon quantum dots.

One of the concerns of today's industrial societies is to achieve sustainable development through the reduction of waste materials or the decrease in the emission of greenhouse gases such as CO2 which today is stated in many international agreements and requirements for it has been concluded by the agreements between the countries of the world, and due to the increasing trend of global warming it is possible to create more encouraging or binding agreements, therefore many researchers are trying to achieve these goals. There are various ways to reduce the production of greenhouse gases during the construction of parts and building materials, and a significant part of them have been directed towards the production of a new type of environmentally friendly material called geopolymers. This category of materials, which have the ability to use waste materials as raw materials for their construction due to their very good mechanical and chemical properties, has been able to find various applications that, due to their similarity to concrete structures, are suitable alternatives for them as structures and building materials. In the following research, an attempt has been made to study geopolymers from the point of view of their formation, applications and properties.