Papers by Keyword: Iron

Abstract: Amorphous metal alloys have unique properties and are widely used. The unique properties of such materials are accompanied by problems of mechanical strength. The existing methods of their processing are not unambiguous and require a certain approach. In practice, laser technologies allow us to optimize the complex properties of such materials. The selection of optimal processing modes, including the influence of the gas phase, allows you to locally affect the material, increase the microhardness in certain areas. The absence of the influence of the processing medium on the mechanical properties is confirmed. Local impact on the surface sample also leads to an increase in crack resistance. In general, nanosecond laser exposure can be an effective tool for controlling the mechanical characteristics of an amorphous nanocrystalline material.

Abstract: Our investigations show that electrochemical corrosion of copper is faster than electrochemical corrosion of aluminium at temperatures below 100°C. Literature data analysis shows that the Al atoms diffuse faster than the Cu atoms at temperatures higher than 475°C, Al rich intermetallic compounds (IMCs) are formed faster in the Cu-Al system, and the Kirkendall plane shifts toward the Al side. Electrochemical corrosion occurs due to electric current and due to diffusion. An electronic devise working time, for example, depends on initial copper cover thickness on aluminium wire, connected to the electronic devise, temperature, and volume and dislocation pipe diffusion coefficients, so copper, iron, and aluminium electrochemical corrosion rates are investigated experimentally at room temperature and at temperature 100°C. Intrinsic diffusivities ratios of copper and aluminium at different temperatures and diffusion activation energies in the Cu-Al system are calculated by proposed here methods using literature experimental data. Dislocation pipe and volume diffusion activation energies of pure iron are calculated separately by earlier proposed method using literature experimental data. Aluminium dissolved into NaCl solution as the Al³⁺ ions at room temperature and at temperature 100°C, iron dissolved into NaCl solution as the Fe²⁺ (not Fe³⁺) ions at room temperature and at temperature 100°C, copper dissolved into NaCl solution as the Cu⁺ ions at room temperature and as the Cu⁺ and the Cu²⁺ ions at temperature 100°C. It is found experimentally that copper corrosion is higher than aluminium corrosion, and ratio of electrochemical corrosion rates, k_Cu/k_Al>1, decreases with temperature increasing, although iron electrochemical corrosion rate does not depend on temperature below 100°C. It is obvious, because the melting point of iron is more higher than the melting point of copper or aluminium. It is calculated that the copper electrochemical corrosion rate is approximately equal to aluminium electrochemical corrosion at temperature about 300°C, so copper can dissolve into NaCl solution mostly as the Cu²⁺ ions at temperature about 300°C. The ratio of intrinsic diffusivities, D_Cu/D_Al<1, increases with temperature increasing, and the intrinsic diffusivity of aluminium could be approximately equal to the intrinsic diffusivity of copper at temperature about 460oC. Intrinsic diffusivities ratios in the Cu-Zn system at temperature 400°C and in the Cu-Sn system at temperatures from 190°C to 250°C are analyzed theoretically using literature experimental data. Diffusion activation energies and pre-exponential coefficients for the Cu-Sn system are calculated combining literature experimental results.

Abstract: The article deals with the problems of withstanding harsh temperatures by steel and iron. The authors of the work discuss iron denser high-temperature of γ modification and maximums and minimums of impact. In addition, the article analyses the transformations of iron and anomalies of properties: peak of heat capacity, acceleration of diffusion, etc. The authors take into account the consensus on the causes of polymorphism and the theoretical model of ferromagnetism. Besides, there is a consideration of "transformation" in interaction between Fe atoms that produce anomalies of steel properties. It is necessary to note the transformation detected by anomalies of any properties including mechanical. In the presented work the authors have made an attempt to prove transformations in iron at ~650 °C on the basis of extreme values of hardness and microhardness, metallographic structure, parameters of fine structure, precipitation resistance force depending on temperature. Therefore, the analysis of literature sources on physical and mechanical properties of iron and its derivatives has been made.

Abstract: This work represents the characterization of materials surface before and after laser processing with macrophotography, optical metallography, and scanning electron microscopy before and after thermal exposure. The factors influencing the reliability of the laser-induced code readability have been determined as color and contrast. The range of stability of the code readability under thermal influence on the structural materials under study was determined, which allows improving the reliability of the laser-induced marking codes readability. The research objects in this paper were samples of the following materials: alloys based on copper, aluminum, and iron with laser-induced codes of various types applied on the surface. This work aimed to research the stability of laser-induced codes readability after thermal exposure using macrophotography, optical metallography and scanning electron microscopy on structural materials of various purposes before and after laser processing (when forming a binary matrix code). The research results obtained and presented in this article on the stability of laser-induced codes reading under thermal action on structural materials can be used in different fields of industry, when marking products of heavy, general, medium, and precision engineering, as well as for marking metal products and blank parts. The results of this research are also planned to be used for further analysis of the occurring damage, leading to reading errors due to mechanical and chemical influences. It is planned to evaluate the limit values of the parameters that determine the degree of degradation at which the encoding will be considered to have lost the recognizing ability. Requirements for the quality and permissible code damage will also be developed to ensure their reliable identification.

Abstract: Crude petroleum filters were prepared from low-cost materials based on kaolin powder and combustible materials as palm fronds powder which acts as pore creating agent. The samples with different content (10, 20, 30,40) wt% of palm fronds powder (P.F) were fabricated using a dry pressing method and fired at 1100 °C. Crude petroleum filters were characterized by X-ray diffraction (XRD), energy dispersive analysis (EDS) and Scanning electron microscopy (SEM). Physical properties (linear shrinkage, apparent porosity, water absorption, apparent density), mechanical properties (compressive strength and diametrical strength ) and Metallic Content.

Abstract: The shortage of water has become a serious problem in the development of the steel industry in China. Therefore,it is important for research to be done in environment management, estimating the potential improvement of steel industry. This study propose an improved water footprint model of steel production based on the water footprint network methodology and the life cycle assessment framework. The result shows that the water footprint of steel production is 41.09m³/t, which requires larger amounts of direct blue water. The case of China highlights the relevance of clean production, energy efficiency measures, and grading utilization on reducing the water footprint of steel production.

Abstract: Magnetic nanoparticles (MNPs) have many uses for biomedical applications including drug delivery, magnetic resonance imaging (MRI) contrast agents, theranostics and hyperthermia. MNPs photo-thermally heated by laser light could be used to treat the typically difficult to access tumors such as glioblastomas. Due to their high magnetic saturation, monometallic iron nanoparticles would have an edge over iron oxide nanoparticles currently being investigated for hyperthermia. The goal of this study was to synthesize spherical iron nanoparticles less than 10 nm in diameter by thermal decomposition. The ability of various biocompatible coatings to protect the metallic iron nanoparticles from oxidation was investigated. Coatings studied included Brij, polyethylene glycol and iron oxide. Transmission electron microscopy and Mössbauer spectroscopy were utilized to characterize the coated and uncoated iron nanoparticles’ size and oxidation state to evaluate the effectiveness of the coatings and the procedures in which the coatings were applied. A ferrite shell was found to provide the best stabilization; however, its longer synthesis time increased particle size distribution. Polymer coatings provided biocompatibility but did not prevent oxidation.

Abstract: The journey toward foundry and the increasing implementation of Powder Metallurgy are evoking replacing traditional Sand Casting, thus, creating new challenges and opportunities. To take advantage of these opportunities and deal with the challenges, we must gain a holistic understanding of the emerging technical interactions and apply new approaches and methods when introducing new technologies and designing Powder Metallurgy. In this paper, we present the findings of a systematic literature review, consisting of quantitative and qualitative data, focusing on investigating Powder Metallurgy, as an alternative to traditional Sand Casting, by comparing certain characteristics of either process to synthesize the existing information of each method and to present an overview of manufactured materials. Although results indicate an increasing current trend in research publications, showing Powder Metallurgy with many advantages over traditional casting, the latter continues to be implemented as the preferred option in industries with low-level casting production. Given that the studies indicate greater advances in Powder Metallurgy methods over traditional casting, we identified the need for more research on the former under different contexts and therefore recommend it as an approach for future studies of metal casting. This review both reorganizes the available knowledge on Powder Metallurgy, as well as it makes an important methodological contribution by applying a review in Materials science, where there is little to no systematic research, which often means failure to provide sufficient help to implement Powder Metallurgy. Based on these findings, we point to future research needs, highlighting the need for further empirical evidence and improved collaboration between the topics of Mechanical Engineering, Manufacturing Processes, and Materials science, as well as with practitioners.

Abstract: In this work, we have investigated the localized surface plasmon resonance profile of promising non-noble metals such as nickel (Ni), iron (Fe), and permalloy (Ni₈₀Fe₂₀) as an alternative plasmonic material. The nanoparticle formed a sphere with varying the diameter from 10 nm to 200 nm with increment 10 nm, and the medium of nanoparticles is air (1+0i). The calculation was carried out by metallic nanoparticle boundary element method package. Furthermore, our result shows that increasing diameter of particles (iron, nickel, and permalloy) would increase the efficiency of ratio scattering to absorption, and the LSPRs peak led to shift to lower energy (red-shift). The ratio of scattering to absorption indicates a strengthening of radiative damping in large particle-size which largely used in biological cell imaging. However, iron’s efficiency much lower than nickel and permalloy. For example, at the highest diameter, such 200 nm, the efficiency of iron is just over around 1.25 while nickel and permalloy well under nearly 2.0. In addition, nickel and permalloy’s LSPR happened in visible range. Our results serve a systematic understanding of the shifting spectrum pattern for prospective ferromagnetic materials

Abstract: The one of major impurities in quartz is iron, which has a great impact on the properties of the material and should be be strictly removed in many applications. In this study, a low-energy consumption, simple, fast processing is introduced by combination microwave treatment with different acid leaching. Selective heating of microwaves is used to process quartz, causing local phase changes to improve the purification effect. Acid leaching was used to remove the iron in the quartz matrix. Under optimized conditions, the iron content can be reduced to below 0.167 ppmw with one single purification pass.