Effects Of Rare Earth Elements Research Articles

Exploring synergistic and individual causal effects of rare earth elements and renewable energy on multidimensional economic complexity for sustainable economic development

The ongoing global energy transition has highlighted the instrumental role of rare earth elements (REEs) in achieving green growth through the deployment of renewable energy technologies, establishing a hypothetical progressive synergistic association between them. Therefore, testing this hypothetical synergy and its potential causal effects on economic and technological proxies based on empirical foundations becomes imperative in addressing rampant climatic change. First, we employed Deep Learning algorithms to explore the combined effects of this synergy on Multidimensional Economic Complexity (MEC) as an index using panel data of the largest producers of REEs from 1990 to 2023. Second, Temporal Causal Modelling (TCM) was employed to unveil the directional causality between REEs and renewable energy, as well as their causal roles in driving economic complexities. The deep learning models accurately predicted the positive role of this synergistic relationship in promoting overall MEC. Then, the results of TCM reveal that REE production increases renewable energy use and reduces CO2 emissions. Renewable energy promotes Research and Technology complexities while REE production affects them indirectly through renewables. It implies that harnessing this synergy to enhance economic complexities can, in turn, bolster green economic and technological development while mitigating CO2 emissions and addressing pervasive climate change.

The Role of Rare Earths on Steel and Rare Earth Steel Corrosion Mechanism of Research Progress

Corrosion has always been an important factor affecting the life of steel, which causes huge economic losses every year. How to improve the corrosion resistance of steel has always been a research focus. Adding rare earth elements into steel is an important method to improve the corrosion resistance of steel. In this paper, the effects of rare earth elements on steel are summarized, including the purification of molten steel, modification and modification of inclusions, improvement of grain boundaries by solid solution strengthening, the influence of phase transformation and the refinement of microstructure, and reduction in C and N desolubilization. On this basis, the progress of research on the corrosion resistance mechanisms of rare earth steel is summarized, focusing on rare earth-modified inclusions. This includes the changes in composition and sizes of inclusions by rare earth addition, promoting the transformation of MnS and Al2O3 in rare earth inclusions with regular shapes, smaller sizes and better performance, or composite rare earth inclusions. The corrosion pits that form in the early stages of corrosion are shallow in depth, fewer in number and light in corrosion degree. The effects of rare earth materials on the rust layer include: rare earth promotes the formation of a more stable corrosion product α-FeOOH, and rare earth promotes the formation of a dense rust layer, which covers the surface of the matrix and hinders the transmission of corrosion ions. The protective effect of the rare earth atomic layer on the substrate and the corrosion inhibition effect of rare earth ions are formed by the segregation of rare earth at the interface. In the end, the existing problems in the research into rare earth steel and future research directions are briefly put forward, including improving the addition process of rare earth steel, theoretical guidance on enhancing the corrosion resistance mechanism of rare earth steel, and extending the research from La, Ce, and Y steel to more rare earth steels.

Effect of Rare Earth Elements on Microstructure and Tensile Behavior of Nb-Containing Microalloyed Steels.

The present investigation endeavors to explore the influence of rare earth elements on the strength and plasticity characteristics of low-carbon microalloyed steel under tensile loading conditions. The findings from the conducted tensile tests indicate that the incorporation of rare earths leads to a notable enhancement in the yield strength, ultimate tensile strength, and ductility properties of the steel. A comparative analysis of the microstructures reveals that the presence of rare earths significantly refines and optimizes the microstructure of the microalloyed steel. This optimization is manifested through a reduction in grain size, diminution of inclusion sizes, and a concomitant rise in their number density. Moreover, the addition of rare earths is observed to foster an increase in the volumetric fraction of carbides within the steel matrix. These multifaceted microstructural alterations collectively contribute to a substantial strengthening of the microalloyed steel. Furthermore, it is elucidated that the synergistic interaction between rare earth elements and both carbon (C) and niobium (Nb) in the steel matrix augments the extent of the Lüders strain region during the tensile deformation of specimens. This phenomenon is accompanied by the effective modification of inclusions by the rare earths, which serves to mitigate stress concentrations at the interfaces between the inclusions and the surrounding matrix. This article systematically evaluates the modification mechanism of rare earth microalloying, which provides a basis for broadening the application of rare earth microalloying in microalloyed steel.

Effect of Doping Trace Rare Earth Elements on Corrosion Behavior of EH36 Offshore Platform Steel

EH36 offshore platform steel, La (0.0031%) steel, Ce (0.0027%) steel, and Pr (0.0001%) steel were selected as the research objects. The corrosion of four groups of steel was simulated by immersion experiments. In the presence of Cl− the effect of rare earth elements (La, Ce, Pr) on corrosion was investigated by the weight loss method. The morphology of the corrosion products and the apparent morphology after the removal of the corrosion products were observed by scanning electron microscopy (SEM); the main components of four steel corrosion products were analyzed by X-ray diffraction (XRD). The electrochemical behavior and the influence of temperature and Cl− concentration on the corrosion of the four kinds of steel were analyzed by an electrochemical polarization curve and Nyquist diagram. The results showed that the addition of trace rare earth elements, La, Ce, and Pr, to EH36 offshore platform steel can reduce the corrosion rate and the corrosion current density (Icorr), and increase the charge transfer resistance during the corrosion process. The Icorr of La steel, Ce steel, and Pr steel is 6.59 × 10−5 A·cm−2, 7.57 × 10−5 A·cm−2, and 9.53 × 10−5 A·cm−2, respectively, which is lower than that of EH36 steel (Icorr = 1.82 × 10−4 A·cm−2). The influence of Cl− concentration and temperature on the four steels showed the same trend; that is, with the increase in Cl− concentration, the corrosion rate first rises and then slows down, and with the increase in temperature, the corrosion rate gradually accelerates. Rare earth elements promote the production of more α-FeOOH in the rust layer, and the compactness of this product plays a certain role in protecting the steel matrix. The addition of trace rare earth elements, La, Ce, and Pr (less than 0.004%), improves the corrosion resistance of EH36 steel.

Effects of Ce on the precipitation behaviors and creep properties in 316LN austenitic stainless steel

The effects of Ce on the precipitation behaviors and creep properties in 316LN austenitic stainless steel (316LN) were studied by experiments and first-principles calculations. It was found that Ce in 316LN induces intragranular Laves phase precipitates with an average diameter of 166 nm. Aside from Ce rich in TiN nanoparticles facilitating Laves phase precipitation by heterogeneous nucleation, the solute Ce atom attracting its surrounding Mo atoms favors Laves phase precipitation by homogeneous nucleation. These intragranular Laves phases strongly impede the dislocation climbing and thus enhance the creep resistance. Here, 0.032 wt% Ce addition in 316LN considerably extends the creep life from 313 h to 556 h at 700 °C/150 MPa. These results provide a new insight into profoundly understanding the microalloying mechanism and effects of rare earth elements in heat-resistant steels.

Anti-fading study of Al–Ti–B by adding Ce on 6111 aluminum alloy

It is a practically significant issue to overcome the low efficiency and the short action time of Al–Ti–B master alloy for the grain refinement of aluminum alloys. In this paper, the phase relationship of the Al–Ti–B–Ce system, the effect of rare earth elements on the evolution of the morphology of the refining phases TiB2 and Al3Ti, and the effect of the refiners on the microstructure and properties of the 6111 alloy are investigated. The experimental results show that the addition of rare earths introduces the rare earth phase Ti2Al20Ce into Al–Ti–B. The rare earth phase acts as an effective protective shell, reduces the free energy of Al3Ti, prevents further movement at the Solid/Liquid interface, and inhibits the aggregation and growth of the Al3Ti phase. By adsorbing on the surface of the TiB2 phase, the rare earth reduces the surface energy and size of the TiB2 phase, thus reducing the possibility of agglomeration. The fine and dispersed refining phase results in more effective nucleation sites in the melt, which can maintain grain refining for a long time and has better anti-fading effect. Therefore, the grain refiner Al–5Ti–B + Ce can effectively refine the grain of 6111 alloy, reduce the grain refinement fading shortcoming, and improve the strength and ductility of 6111 aluminum alloy.

Case study of fluorite mineralization using traditional and laser spectroscopic techniques, homret akarem area south eastern desert, Egypt

Green fluorite samples from Homret Akarem, eastern desert Egypt, were investigated by laser-based Raman spectroscopy to study the effect of rare earth elements (REEs) and natural radiation from the surrounding environment on their physico-chemical properties, taking into consideration the geological setting. Geochemical data of trace elements display fluorite enrichment with Y, Pb, Sr, Sn, and other REEs. XRD showed lattice parameters with values higher than those for synthetic fluorite due to the substitution of Ca by Sr and less likely by radiation from U. A considerable shift in the binding energy (BE) for Ca and F obtained from the XPS spectrum indicates that U carried by the hydrothermal solutions formed a discontinuous thin film on the surface of fluorite. Laser-Raman spectroscopy showed strong peaks below 500 cm−1 and both shallow and weak peaks above 500 cm−1. The strong peaks indicate that the substitution of Ca by Sr, point defects, and natural radiation caused by U have a stronger effect on the crystal structure than REEs. Raman spectroscopy supported the initial reports of uranium minerals like Rutherfordine, Kasolite, Soddyite, and Uranophane-alpha.

Evaluation of Holmium(III), Erbium(III), and Gadolinium(III) Accumulation by Cyanobacteria Arthrospira platensis Using Neutron Activation Analysis and Elements' Effects on Biomass Quantity and Biochemical Composition.

Rare-earth elements are released into the aquatic environment as a result of their extensive use in industry and agriculture, and they can be harmful for living organisms. The effects of holmium(III), erbium(III), and gadolinium(III) when added to a growth medium in concentrations ranging from 10 to 30 mg/L on the accumulation ability and biochemical composition of Arthrospira platensis were studied. According to the results of a neutron activation analysis, the uptake of elements by cyanobacteria occurred in a dose-dependent manner. The addition of gadolinium(III) to the growth medium did not significantly affect the amount of biomass, whereas erbium(III) and holmium(III) reduced it up to 22% compared to the control. The effects of rare-earth elements on the content of proteins, carbohydrates, phycobiliproteins, lipids, β carotene, and chlorophyll a were evaluated. The studied elements had different effects on the primary biomolecule content, suggesting that holmium(III) and erbium(III) were more toxic than Gd(III) for Arthrospira platensis.

Tribological, oxidation and corrosion properties of ceramic coating on AISI H13 steel by rare earth-Cr composite boronizing

In this paper, a rare earth-Cr composite boronizing method to prepare boride ceramic coatings for AISI H13 steel was proposed. The effect of rare earth elements and Cr on the microstructure, hardness, wear resistance, high temperature oxidation resistance, and corrosion of boride ceramic layers was researched. The characteristics of the boride layers were investigated by means of X-ray diffraction (XRD), scanning electron microscope (SEM), electron probe microanalysis (EPMA), wear tests, high-temperature oxidation tests, and corrosion immersion tests, etc. The results showed that the boride layer comprised of Fe2B, FeB, CrB and Cr2B phases. The addition of rare earth CeO2 and Cr nanopowder promoted the growth of the boride layer, and its surface hardness increased by 3.5 times compared with that of tempered AISI H13 steel. In addition, the addition of CeO2 and Cr significantly reduced the wear rate of the boride layer, with the surface wear mechanism being abrasive oxidative wear. Furthermore, the oxidation rate of the boride layer was 71 % lower than that of AISI H13 steel, demonstrating excellent high-temperature oxidation resistance; and the boride layer showed good acid corrosion resistance in corrosion immersion tests.

Effects of Rare Earth Elements on Inclusions and Impact Toughness in a Weathering Steel

Effects of Rare Earth Elements on Inclusions and Impact Toughness in a Weathering Steel

Segregation behavior of alloying elements at the fcc-Fe/TiC interface by first principles exploration

In this paper, the effects of rare earth elements on the bonding strength and stability of TiC/fcc-Fe interface are explored by using the first-principles method based on density functional theory. The results show that the Ti terminal is more stable than the C terminal in the process of forming the interface. The alloying elements tend to segregate at position 2 on the side of fcc-Fe. The segregation of Mo, Nb, Cr and Ce alloying elements increases the interatomic electron cloud enrichment and consumption between the interfaces and enhances the Fe–Ti interactions. The d orbitals of Mo, Nb, Cr and Ce and f orbitals of Ce have strong hybridization with Fe-d orbitals and Ti-d orbitals electrons near the Fermi energy level, indicating an increase in bonding strength and stability of the interfaces. When Fe atoms are replaced by W, Ni and Al atoms, the covalent bond strength between interfacial atoms is reduced, thus weakening the interfacial bonding strength. This provides solid theoretical foundation with regard to further application in austenitic heat-resistant steel fields.

Tension-compression asymmetry of temperature dependencies in Mg rare-earth alloys

To reveal the tension-compression asymmetry of temperature-dependency in Mg-RE alloys, uniaxial tensile and compression tests followed by microstructural characterizations were performed on a cast Mg-10Gd-3Y-0.5Zr (wt.%) alloy under various temperatures. The results show that this alloy exhibits anomalous temperature effects on mechanical properties (such as tensile strength and plasticity) during tension, while they are not observed during compression tests, demonstrating that the anomalous temperature effects exhibit loading path dependence. The tension-compression asymmetry of the anomalous temperature-dependency associated with variations in twinning. It is believed that these variations in twinning result from the interplay between the inhibitory effect of rare earth elements on twinning and the promoting effects of elevated temperature or a change in the loading path from tension to compression, with the loading path having a stronger promoting influence than the deformation temperature.

Effect of rare-earth element Y addition on microstructure and mechanical properties of CrFeNi2 medium entropy alloy

In present work, a novel Co-free (CrFeNi2)100-xYx (x = 0, 3, 6, 9) medium entropy alloys (MEAs) were successfully prepared by vacuum arc-melting method. The results revealed that the addition of rare-earth element Y had a great effect on the phase composition of CrFeNi2 MEA, which was transformed from the single FCC phase structure to the duplex structure of the FCC and HCP (YNi5 type) phases. Meanwhile, the phase evolution of the current alloy system was evaluated using the previous criteria (ΔHmix-δ, Ω-δ, Δχ, VEC and Λ). In addition, the volume fraction of the HCP phase increased significantly with the increasing Y content, which caused the obvious grain refinement. On the other hand, the nanoindentation test results revealed that the nanohardness of the HCP phase (∼10.7 GPa) was more than three times of the FCC phase (∼3.4 GPa). The dislocation nucleation types of the FCC phase (3.68 GPa) and the HCP phase (6.46 GPa) were discussed by calculating their maximum initial plastic shear stress. With the increasing Y content, both the hardness and strength of the alloy were significantly improved, but the plasticity deteriorated. The second phase strengthening played a dominant role in the strength improvement of (CrFeNi2)100-xYx MEAs, while both the solid solution strengthening and grain boundary strengthening contributed slightly to the strength increment.

Fate, subcellular distribution and biological effects of rare earth elements in a freshwater bivalve under complex exposure

Rare earth elements (REE) are emerging contaminants due to their increased use in diverse applications including cutting-edge and green-technologies. Their environmental concerns and contradicting results concerning their biological effects require an extensive understanding of REE ecotoxicology. Thus, we have studied the fate, bioaccumulation and biological effects of three representative REE, neodymium (Nd), gadolinium (Gd) and ytterbium (Yb), individually and in mixture, using the freshwater bivalve Corbicula fluminea. The organisms were exposed for 96 h at 1 mg L−1 REE in the absence and presence of dissolved organic matter (DOM) reproducing an environmental contamination. Combined analysis of the fate, distribution and effects of REE at tissue and subcellular levels allowed a comprehensive understanding of their behaviour, which would help improving their environmental risk assessment. The bivalves accumulated significant concentrations of Nd, Gd and Yb, which were decreased in the presence of DOM likely due to the formation of REE-DOM complexes that reduced REE bioavailability. The accumulation of Nd, Gd and Yb differed between tissues, with gills > digestive gland ≥ rest of soft tissues > hemolymph. In the gills and in the digestive gland, Nd, Gd and Yb were mostly (>90 %) distributed among metal sensitive organelles, cellular debris and detoxified metal-rich granules. Gadolinium, Yb and especially Nd decreased lysosome size in the digestive gland and disturbed osmo- and iono-regulation of C. fluminea by decreasing Na concentrations in the hemolymph and Ca2+ ATPase activity in the gills. Individual and mixed Nd, Gd and Yb exhibited numerous similarities and some differences in terms of fate, accumulation and biological effects, possibly because they have common abiotic and biotic ligands but different affinities for the latter. In most cases, individual and mixed effects of Nd, Gd, Yb were similar suggesting that additivity approach is suitable for the environmental risk assessment of REE mixtures.

The Effect of Rare-Earth Elements on the Morphological Aspect of Borate and Electrocatalytic Sensing of Biological Compounds.

Adjusting the morphological characteristics of a material can result in improved electrocatalytic capabilities of the material itself. An example of this is the introduction of rare-earth elements into the borate structure, which gives a new perspective on the possibilities of this type of material in the field of (bio)sensing. In this paper, we present the preparation of borates including La, Nd and Dy and their application for the modification of a glassy carbon electrode, which is used for the non-enzymatic detection of a biologically relevant molecule, vitamin B6 (pyridoxine). Compared with the others, dysprosium borate has the best electrocatalytic performance, showing the highest current and the lowest impedance, respectively, as determined using cyclic voltammetry and impedance tests. Quantitative testing of B6 was performed in DPV mode in a Britton-Robinson buffer solution with a pH of 6 and an oxidation potential of about +0.8 V. The calibration graph for the evaluation of B6 has a linear range from 1 to 100 μM, with a correlation coefficient of 0.9985 and a detection limit of 0.051 μM. The DyBO3-modified electrode can be used repeatedly, retaining more than 90% of the initial signal level after six cycles. The satisfactory selectivity offered a potential practical application of the chosen method for the monitoring of pyridoxine in artificially prepared biological fluids with acceptable recovery. In light of all the obtained results, this paper shows an important approach for the successful design of electrocatalysts with tuned architecture and opens new strategies for the development of materials for the needs of electrochemical (bio)sensing.

Tailoring microstructure evolution and austenite stability of TRIP steels by Rare-Earth micro-alloying

The microstructure evolution and austenite stability of Rare Earth (RE)-alloyed Transformation Induced Plasticity (TRIP) steels subjected to intercritical annealing and isothermal bainitic transformation have been investigated for superior strength-ductility performance. Structure morphology, austenitizing temperature and phase proportion during thermomechanical process were carefully compared, confirming that minor RE additions indeed refined the microstructure, and affected the thermodynamics of austenite and bainite transformation. Austenitizing ranges of TRIP steels were lifted with increasing RE content then stabilized when exceeding 360 ppm; the intercritical austenite reduced but dissolved more CMn atoms, hence the bainite transformation in RE-alloyed TRIP steels was significantly inhibited, which elevated the retained austenite quantity and thermal stability simultaneously. Therein, more austenite nucleated from the structure fragments with RE-refined lamellar morphologies and strictly grew into acicular counterparts or aggregated into clusters. The aggregated austenite, composed of several subgrains with [011¯] coaxial relations or Σ3 60°〈111〉 misorientation but coherent interfaces, were engulfed or being swallowed up by coalescing ferrites in sluggish growth, guaranteeing the higher mechanical stability than intergranular austenite. In this study, the product of strength and elongation of TRIP steels after optimized RE-alloying was increased by 38% as compared to that without RE additions. The micro-alloying effect of RE elements in TRIP steels highlights the innovations of new-generation automotive steels.

Effects of rare earth elements on inclusions, microstructure and impact toughness of spring steel

Effects of rare earth elements on inclusions, microstructure and impact toughness of spring steel

Effect of Rare Earth Elements (Y, La) on Microstructural Characterization and Corrosion Behavior of Ternary Mg-Y-La Alloys.

In this study, the microstructural properties and corrosion behavior of RE elements (Y, La) added to magnesium in varying minors after casting and homogenization heat treatment were investigated. Three-phase structures, such as α-Mg, lamellae-like phases, and network-shaped eutectic compounds, were seen in the microstructure results. The dendrite-like phases were evenly distributed from the eutectic compounds to the interior of the α-Mg grains, while the eutectic compounds (α-Mg + Mg) RE (La/Y)) were distributed at the grain boundaries. According to the corrosion results, the typical hydroxide formation for lanthanum content caused the formation of crater structures in the material, and with the increase in lanthanum content, these crater structures increased both in depth and in density. In addition, the corrosion products formed by Y2O3 and Y(OH)3 in the Mg-3.21Y-3.15 La alloy increased the thickness of the corrosion film and formed a barrier that protects the material against corrosion. The thinness of the protective barrier against corrosion in the Mg-4.71 Y-3.98 La alloy is due to the increased lanthanum and yttrium ratios. In addition, the corrosion resistance of both Mg-3.21Y-3.15 La and Mg-4.71 Y-3.98 La alloys decreases after homogenization. This negative effect on corrosion is due to the coaxial distribution of oxide/hydroxide layers formed by yttrium and lanthanum after homogenization.

Biochemical indicators of the lipid metabolism in workers involved in the processing of raw materials and production of rare metal products

Introduction. In recent years, the use of rare earth elements has been expanding in various innovative research and high-tech industries, which leads to an increase in the volume of their extraction and processing and makes it possible to develop a negative impact on the health of workers under conditions of long-term industrial exposure to rare earth elements with the air of the working area.
 The purpose of the work is to study and evaluate the deviations of the biochemical parameters of the lipid spectrum in workers, due to the chemical factors of the technological process of processing raw materials and production of rare metal products.
 Materials and methods. The study and evaluation of the content of rare earth elements in the blood of workers, the study of biochemical parameters, statistical analysis, modelling of cause-and-effect relationships were carried out.
 Results. Workers exposed to rare-earth elements with the air of the working area (100% of workplaces) showed increased concentrations of holmium, dysprosium, yttrium, neodymium, niobium and terbium in the blood from 1.5 to 2.5 times compared to similar indicators in workers who were not associated with technological process. Elevated levels of total cholesterol, VLDL and triglycerides in blood serum, a decrease in the total antioxidant activity of blood plasma in workers relative to the physiological norm and similar indicators in the comparison group were established. A significant relationship of the identified deviations with an increased blood concentration of niobium, dysprosium and holmium has been proven.
 Limitations. The study took into account the aerogenic inhalation effect of rare earth elements on the health of workers involved in the processing of raw materials and production of rare metal products. 
 Conclusion. Long-term inhalation exposure to rare earth elements contained in the air of the working area caused changes in biochemical parameters, reflecting the depletion of antioxidant defense resources, inducing disorders of lipid metabolism. The identified negative effects in workers can lead to pro-atherogenic vascular inflammation under conditions of continuing industrial exposure. The obtained results should be taken into account for the development of recommendations aimed at minimizing the negative consequences of the impact of the studied chemical factors of the labour process on the health of workers.

The influence of rare earth elements (Y, Sc) on the interfacial binding properties between the precipitation phases Fe2B, FeB and the matrix Fe in boron steel

Boron steel is a commonly used wear-resistant material in the metallurgical and mining industries. The performance of its hard precipitated phases and their coordination with the matrix are currently the main focus of attention. In this paper, the mechanical properties of the precipitated phases in boron steel were studied using first-principles calculations. Fe2B and FeB have high hardness, and the low-index surfaces with the lowest surface energy are (111). The low-index surface of the matrix Fe is (110). The interfacial properties between the matrix and the precipitated phases (Fe2B and FeB) were calculated. The interfacial energy of Fe(110)/FeB(111) is 0.3113 eV/Å2, and the interfacial energy of Fe(110)/Fe2B(111) is 0.3987 eV/Å2. The effects of rare earth elements Y and Sc on the interface bonding strength between (Fe2B, FeB) and matrix Fe were also examined. It was found that Y-doped Fe(110)/FeB(111) interface is more stable than that doped with Sc; however, the Sc-doped Fe(110)/Fe2B(111) interface is more stable than that doped with Y. The above calculation results indicate that rare earth elements play a promoting role in the micro-interface of boron steel, and the coordination between the precipitated phases and the matrix significantly improves the wear resistance of boron steel.