Addition Of Rare Earth Metals Research Articles

MICROSTRUCTURE AND MECHANICAL PROPERTIES OF LEAD BABBIT B(PbSb15Sn10) WITH SOME RARE EARTH METALS (La, Ce, Nd)

The article presents a detailed study on the effects of rare earth elements, such as lanthanum (La), cerium (Ce), and neodymium (Nd), on the microstructure and mechanical properties of lead-based babbitt alloy grade B (PbSb15Sn10). The study involves a thorough analysis of the changes in the alloy's structure and its mechanical characteristics under the influence of these rare earth additives, which helped to reveal their role in shaping the material's properties. It is shown that the addition of rare earth metals to the lead babbitt significantly improves its strength characteristics, leading to a longer service life and high operational reliability. The research established that adding rare earth metals increases the hardness of the original babbitt alloy to 187 MPa. Cerium is identified as the most effective alloying component in terms of enhancing hardness and strength. The results of the microstructure analysis of the babbitts indicate that the introduction of small amounts of rare earth metals has a substantial modifying effect on the alloy's structure, resulting in significant refinement of the eutectic structure, represented by Pb+SbSn+γ phases, in the babbitts. Additionally, during the eutectic crystallization process, the formation and precipitation of intermetallic phase inclusions, involving antimony and rare earth metals, were observed in the babbitt structure. Rare earth metals alter the alloy structure by reducing the grain size.

Effect of Addition of Rare Earth Metal (Ce) on the Microstructure, Mechanical Properties and Corrosion Behavior of NiTi Alloys

Effect of Addition of Rare Earth Metal (Ce) on the Microstructure, Mechanical Properties and Corrosion Behavior of NiTi Alloys

Summary of the Research Progress on Advanced Engineering, Processes, and Process Parameters of Rare Earth Green Metallurgy.

The addition of rare earth metals to aluminum alloys can effectively improve their corrosion resistance and has been widely used in the aerospace and military industries. However, the current methods for the preparation of rare earth metals involve long processing steps, high energy consumption, and high carbon emissions, which severely constrains the development of aluminum alloys. Its output is further developed. To this end, this paper reviews mainstream rare earth production processes (precipitation methods, microemulsion methods, roasting-sulfuric acid leaching methods, electrochemical methods, solvent extraction methods, and ion exchange methods) to provide basic information for the green smelting of rare earth metals and help promote the development of green rare earth smelting. Based on the advantages and disadvantages of each process as well as recent research results, the optimal process parameters and production efficiency were summarized. Studies have concluded that the precipitation method is mostly used for the recovery of rare earth elements and related valuable metals from solid waste; the microemulsion method is mostly used for the preparation of nanosized rare earth alloys by doping; the roasting-sulfuric acid leaching method is mostly used for the treatment of raw rare earth ores; and the molten salt electrolysis method is a more specific method. This is a green and environmentally friendly production process. The results of this study can provide direction for the realization of green rare earth smelting and provide a reference for improving the existing rare earth smelting process.

Effect of Gd, V, and Y Alloying on the Corrosion Properties of Fe-Mn-Ni-Al Fe-based Shape Memory Alloy

Shape Memory Alloys (SMA) are widely utilized in numerous industrial applications nowadays. Significant attention has been given to Fe-based SMA in civil engineering applications due to their high strength and reasonable cost. Researchers are striving to improve the corrosion resistance of these alloys so they can be utilized in marine environments. This article focuses on the effect of Gd, V, and Y alloying on FeMnNiAl based SMA. The phases and morphological effects were characterized using X-Ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Energy Dispersive Spectroscopy (EDS). To examine the corrosive nature of the Fe-based SMA system, a potentiodynamic analysis and electrochemical impedance spectroscopy (EIS) tests were performed in 3.5% NaCl solution. Results show that the addition of Gd rare earth metal has improved the overall corrosion efficiency of Fe-based SMAs by 48%.

Influence of rare earth metals on inclusion modification of dual phase steel

ABSTRACT Inclusions are very critical in advanced high-strength steels as they are used in automobile and aerospace industries in which modification of inclusions is required. In this investigation, Rare Earth Metals (REM) have been used to control and modify the inclusions in the steel. With the addition of REMs, the total sulphur content present in the steel has been reduced by 22%. An inclusion study has been performed using the inclusion classifier and ISO-4967 method. Total inclusions and the number of inclusions at higher indexes (severity) are reduced by adding REM. The chemistry of the modified inclusions, such as oxides, sulphides and oxysulphides of REM, is compatible with the steel matrix and does not have harmful effects. With the addition of REM, the global cleanliness index value at 1.5, 2, 2.5 and 3 indexes are decreased. This may be attributed to the REM breaking down the stringers. Whereas value has been increased at 0.5 and 1 indexes after the addition of RE metals, inclusions sizes are reduced, which is not harmful to the properties of the steel.

The Promotional Effect of Rare Earth on Pt for Ethanol Electro-Oxidation and Its Application on DEFC

Bimetallic Pt3Eu/C, Pt3La/C, and Pt3Ce/C electrocatalysts have been prepared, characterized, and tested for ethanol electro-oxidation (EEO). The materials were synthesized by chemical reduction with NaBH4, rendering nanosized particles with actual compositions close to the nominals and no alloy formation. X-ray photoelectron spectroscopy (XPS) confirmed that the auxiliary rare-earth metals were present on the surface in oxide form. The electrochemical analyses in acid and alkaline EEO evidenced that, compared to Pt/C, the addition of rare earth metals in the form of oxides reduced the onset potential, increased the current density, and enhanced the stability. The results were fully confirmed in the DEFC single-cell measurements. Finally, the presence of rare earth metals in the oxidized form increased the percentage of acetic acid as the final product, making the electrocatalysts more selective and efficient than Pt/C, where acetaldehyde was the main product.

PHASE FORMATION DURING ALUMINOTHERMAL REDUCTION OF Ti, Nb, Gd (Y) FROM OXIDES

Alloys based on titanium and aluminum with additions of niobium and rare-earth metals have unique mechanical and heat-resistant properties, and also it likely that such alloys would have increased corrosion resistance. The method of thermodynamic modeling using the HSC program was used to study a system with aluminum consumption varying in the range from 0 to 100% of the mass of the initial charge. The features of phase formation in Al–[50TiO2–5Nb2O5–1Y2O3 (Gd2O3)] systems have been studied. The calculation of the heat balance of the process at 1600°C and 44% of Al was – 0.196 MJ per 1 kg of charge, which indicates the possibility of its occurrence with only the aluminothermic reactions. The reduction of titanium and niobium can proceed by reactions through the formation of their oxides of lower valency – TiO, NbO2, NbO. The aluminothermic reduction of gadolinium is thermodynamically possible only at temperatures below 1200°C. The reduction of yttrium through the interaction of Y2O3 with aluminum with the formation of AlY, Al2Y3 AlY2 compounds for the range of 1000–1800°C is thermodynamically impossible. The results of thermodynamic modeling of interactions correlated well with the data of differential thermal and X-ray phase analysis using STA 449 F3 Jupiter (NETZSCH) synchronous thermal analysis and XRD-7000 diffractometer (Shimadzu) with automatic program control, respectively. It was found that the process enters the active phase after the appearance of liquid aluminum and, apparently, is accompanied by exothermic effects with the formation of double and triple intermetallic compounds of aluminum with rare (Nb, Ti) and rare earth (Gd, Y) metals. Transformation of titanium dioxide and niobium pentoxide in the process of transformations is likely carried out through successive and parallel stages of formation of simple and complex oxides with low oxidation states. At the initial stages of the interaction of aluminum with oxides, niobium and titanium aluminides are mainly formed. At subsequent stages, the formation of more complex compounds is observed. At temperatures above 1300°C, ternary intermetallic compounds Al43Nb4Gd6, Ti4Al20Gd and Ti4Al3Y6, Al3Ti, Al0.23Nb0.07Ti0.7 are formed. Gadolinium and yttrium tend to form complex intermetallic compounds in such systems.

Abnormal electrical resistivity of Co-Fe-Si-B-Nb-R alloys in amorphous and crystalline states

Electrical resistivity of Co48Fe25Si4B19Nb4 amorphous alloy and with small additions of rare-earth metals ( = Nd, Sm, Tb, Yb) was studied using the AC four-probe method. It was found that these alloys have a specific behavior of electrical resistivity after crystallization-temperature dependences of resistivity at cooling are non-linear and can be fitted as ln R~ T-1/4. Keywords: amorphous alloys, metallic glasses, electrical resistivity, rare-earth metals.

Особенности электрического сопротивления сплавов Co-Fe-Si-B-Nb-РЗМ в аморфном и кристаллическом состояниях

Electrical resistivity of Co48Fe25Si4B19Nb4 amorphous alloy and with small additions of rare-earth metals (R = Nd, Sm, Tb, Yb) was studied using the AC four-probe method. It was found that these alloys have a specific behavior of electrical resistivity after crystallization - temperature dependences of resistivity at cooling are non-linear and can be fitted as lnR ~ T-1/4.

Effects of rare earth metals on microstructure, mechanical properties, and pitting corrosion of 27% Cr hyper duplex stainless steel

Abstract This research focuses on the addition of low-cost rare earth metals (REMs) to improve the comprehensive properties of hyper duplex stainless steels (DSSs). The effects of REM on the microstructure, mechanical properties, and pitting corrosion of hyper DSSs were analyzed by optical/scanning electron microscope metallographic examination, X-ray diffraction analysis, tensile test, impact test, and potentiodynamic polarization test. With the addition of REM, micro/nanoscale REM inclusions were formed, and the microstructure of the alloy was refined. With the increasing content of REM, the average diameter and area of inclusions in the alloy decreased at first and then increased. While the mechanical properties showed a trend of first increasing and then decreasing. An appropriate amount of stable REM inclusions could reduce the susceptibility of pitting corrosion and improve the pitting corrosion resistance of the alloy. The hyper DSSs with REM content in the range of 0.018–0.031 wt% have excellent mechanical properties and pitting resistance.

Effect of the Rare Earth Metals (Tb, Nd, Dy) addition for the modification of nickel catalysts supported on alumina in CO2 Methanation

In the current research, a group of rare-earth metals functionalized mesoporous Ni-M/Al2O3 (M = Tb, Dy, Nd) composite oxides were prepared by the one-pot sonochemical pathway and applied in the CO2 methanation procedure. Promoters can partially influence the textural and catalytic characteristics of Ni–Al2O3 catalysts. Physicochemical characteristics of the as-fabricated catalysts were identified utilizing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Energy-dispersive X-ray spectroscopy (EDS), Temperature Programmed Reduction (H2-TPR), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), and Brunauer-Emmett-Teller (BET) analyses. Among the specimens, the catalyst modified by Terbium (Tb) manifested better catalytic performance and CH4 selectivity, particularly at low temperatures (350–400 °C). The influence of reaction temperature (200–500 °C) was scrutinized below space velocity (GHSV) of 25,000 ml/gcath, atmospheric pressure, and stoichiometric ratio of CO2 to H2 (1: 4). The impact of the desired content of nickel and terbium was examined. The 25Ni–5Tb–Al2O3 operates the best function for CO2 methanation, which can attain the highest CO2 conversion of 66.93% at 400 °C at atmospheric pressure. The superior catalytic performance of 25Ni–5Tb–Al2O3 could be assigned to the appropriate fabrication method and the promotion effect of Terbium. The synthesis effect could be assigned to its large surface area, obtaining by the hot spot mechanism. The addition of Terbium promotes the Ni distribution on the supports as well as accelerates the positive reaction due to the oxygen vacancies of Terbium. Besides, these outcomes could be defined with the maximum distribution of active nickel sites on the catalyst and improvement in the catalyst reduction ability at low temperatures.

Synthesis of Pt-based TS-1 catalysts for selective hydrogenation to produce C15–C18 alkanes from the FAME: Effect of rare-earth metal additives

Green biodiesel is a clean, renewable, and environmental-friendly biofuel, which is commonly produced through catalytic conversion of lipids. The properties of Pt-based catalyst carriers and additives are important factors determining the production of green biodiesel. Herein, titanium silicalite-1 (TS-1) with a large specific surface area was synthesized by a hydrothermal crystallization process, and the rare-earth metal additives including LaOx, CeOx, PrOx, and YOx were used to modify Pt/TS-1 on the fatty acid methyl ester (FAME) hydrotreatment to enhance the selectivity of C15–C18 alkanes. It is shown that the addition of rare-earth metals decreases the particle size of Pt, increases the content of Pt0 species, and changes the major reaction pathway from hydrodecarbonylation (DCO)/hydrodecarboxylation (DCO2) to hydrodeoxygenation (HDO). The Pt–Ce/TS-1 showed the best catalytic performance on the FAME hydrotreatment due to its smaller active metal particle size, more amounts of weak acid, abundant oxygen vacancies, and more content of low chemical states of Pt. The liquid yield, efficiency of deoxygenation, and selectivity of C15–C18 alkanes were 75.7%, 100%, and 97.3% over Pt–Ce/TS-1. The heating value of upgraded liquid products from Pt–Ce/TS-1 reached 49.1 MJ/kg. This work provides a new idea for Pt-based TS-1 catalysts in the preparation of green hydrocarbon biodiesel.

Technology for obtaining a deposited catalyst based on an aluminosilicate matrix modified with europium oxide

The number of cars used worldwide is constantly growing. In this regard, the problem of combating atmospheric pollutants - exhaust gases of internal combustion engines is of particular relevance. Over the years, automakers have made many improvements to car engine design and fuel systems to meet pollution limits. One of the best solutions to this problem is the use of a so-called catalytic converter (converter) or simply a catalyst with a high content of noble metals, the main function of which is the simultaneous oxidation of unburned hydrocarbons and CO, as well as the reduction of nitrogen oxides. It was found that the addition of rare earth metals to Pd, Pt catalysts improves their properties and reduces the proportion of noble metals in the composition of catalysts. The paper presents the results of a study of complexation in the Eu3+-ligand system, where the ligand is an organic acid, by photocolorimetric and potentiometric methods. In the Eu3+-gallic acid system, a stable complex of the composition MeLnx – 1:2 is formed. In the Eu3+- oxalic acid system, a stable complex of the composition MeLnx – 1:1 is formed. In the Eu3+-valine system, a stable complex of the composition MeLnx – 1:2 is formed. A new technique for obtaining complex compounds is shown, consisting in adding hydrogen peroxide H2O2 to a solution containing solutions of Eu3+ salt and organic acid in an aqueous-alcoholic medium to block the reduction of Eu3+→Eu2+. A technology for obtaining a automotive catalyst has been developed, consisting of successive stages: obtaining complex compounds, applying the obtained complex compounds to ceramic block matrices, drying, applying platinum (palladium) acid, calcination. The presence of the Eu3+ ion in the ceramic matrix is proved by the method of elemental analysis. The technology can be applied to solve the problem of environmental pollution, such pollutants as exhaust gases of cars containing a lot of harmful substances in their composition.

Mechanical properties and corrosion resistance of Mg-RE cast alloys and their plasma electrolytic oxidation

The effect of heat treatment on the mechanical properties (hardness, plasticity, yield and tensile strength) and corrosion resistance of several cast magnesium alloys with additions of rare earth metals (Y, Nd and Gd), and their surface modification by plasma electrolytic oxidation (PEO) were investigated. It was found that the heat treatment of the alloys results information of Mg12YZn, Mg3Zn3Y2 and Mg24Y5 based LPSO-phases and causes an increase in hardness and tensile strength by 5-7 and 20-25%, respectively, but at the same time, corrosion resistance of the alloysdrops by 10-20 times. PEO of the alloys after heat treatment reduced the corrosion currents by 1-3 orders of magnitude without changing the corrosion potential.

Gadolinium doped CeO2 for efficient oxygen and hydrogen evolution reaction

Hydrogen evolution reaction (HER) is a significant half reaction in water splitting and it is spirit of energy storage and conversion applications. Recently, high durability and catalytic activity of effective electrodes are necessary to enlarge clean and sustainable energy sources. However, overcoming the overpotential and to improve HER and OER performance is still one of the complicated tasks. Hence, in this present work, gadolinium (Gd) doped cerium oxide (CeO2) was successfully synthesized through a facile co-precipitation method. High intense peak at 28.5° clearly indicated CeO2 cubic structure formation identified by using X-Ray diffraction. The optical phonon mode of F2g and oxygen vacancies mode was detected by using Raman spectra. The optical properties of CeO2 were detected with help of photoluminescence spectroscopy (PL). Fourier-transform infrared (FTIR) spectroscopy confirmed Ce-O vibration of CeO2 crystal existence. Surface morphology of CeO2 was thoroughly studied by using SEM images. HER and OER activity of pristine and Gd doped CeO2 was thoroughly investigated with the help of linear sweep voltammetry. Compared to pristine CeO2, high content of Gd doped CeO2 exhibited excellent HER and OER activity with low overpotential (99 mV for HER and 369 mV for OER) and small Tafel slope (211 mV/dec for HER and 183 mV/dec for OER). Addition of rare earth metal influenced the structural and catalytic properties of optimized metal oxide. Hence, the incorporation of Gadolinium in CeO2 plays a crucial role to enhance both HER and OER performance and it is one of the good candidates for energy conversion applications.

Effect of Rare Earth Metals (Ce and La) Addition on the Performance of Al-Si-Cu-Mg Cast Alloys

Effect of Rare Earth Metals (Ce and La) Addition on the Performance of Al-Si-Cu-Mg Cast Alloys

Effects of rare earth modifying inclusions on the pitting corrosion of 13Cr4Ni martensitic stainless steel

• ASPEX PSEM, SKP, SEM, TEM and electrochemical methods are employed to study corrosion behavior of 13Cr4Ni steel modified with rare earth metals. • Rare earth metals change the composition, size and quantity of inclusions in steel. • The addition of rare earth metals has a significant effect on both metastable and stable pitting processes, the optimum content of rare earth elements (La, Ce) added is 0.021%. • The mechanism of pitting corrosion induced by rare earth inclusions is revealed. In this study, the pitting corrosion behavior of 13Cr4Ni martensitic stainless steel (BASE) and that modified with rare earth (REM) in 0.1 mol/L NaCl solution were characterized. Techniques such as automatic secondary electron microscope (ASPEX PSEM detector), scanning electron microscope (SEM), transmission electron microscope (TEM), scanning Kelvin probe force microscope (SKP), potentiodynamic and potentiostatic polarizations were employed. The results obtained indicate that BASE steel contains Al 2 O 3 /MnS, Al 2 O 3 and MnS inclusions, while REM steels contain (La, Ce, Cr, Fe)-O and (La, Ce, Cr, Fe)-O-S inclusions. Compared with BASE steel, REM steel is more susceptible to induce the metastable pitting nucleation and repassivation, whereas it restrains the transition from metastable pitting to stable pitting. Adding 0.021% rare earth element to BASE steel can reduce the number and area of inclusions, while that of 0.058% can increase the number and enlarged the size of inclusions, which is also the reason that pitting corrosion resistance of 58REM steel is slightly lower than that of 21REM steel. In the process of pitting corrosion induced by Al 2 O 3 /MnS inclusions, MnS is preferentially anodic dissolved, and also the matrix contacted with Al 2 O 3 is subsequently anodic dissolved. For REM steels, anodic dissolution preferentially occurs at the boundary between inclusions and matrix, while (La, Ce, Cr, Fe)-O inclusions chemically dissolve in local acidic environment or are separated from steel matrix. The chemically dissolved substance (La 3+ and Ce 3+ ) of (La, Ce, Cr, Fe)-O inclusions are concentrated in pitting pits, which inhibits its continuous growth.

Influence of rheocasting and rare earth metals on the 3D-microstructure of ZK60 Mg-alloy measured by multiscale X-ray computed tomography

Light weighting has been a key issue to meet stringent requirements on greenhouse gas emissions. One possible way of weight reduction is the substitution of heavier components with lighter metals like Magnesium. In this work, the internal architecture of cast and hot rolled ZK60 alloys with and without addition of 1.5 wt% rare earth metals (RE) has been investigated. The alloys were produced by permanent mould indirect chill cast (PMICC), while the material with 1.5 wt% RE was manufactured by additional rheocasting (RC). A multi-resolution procedure using X-ray computed tomography (XCT) was performed to investigate the alloys in size ranges from meso- (cast blocks) to micro-scale (microstructure). The voxel resolutions used were between (115 μm)3 down to (0.8 μm)3. Morphometric parameters such as volume, volume fraction, connectivity, structure separation, structure thickness etc. were calculated to characterize the 3D-microstructure of the various alloys. The alloys showed no detectable cracks in the as-cast condition, while macroscopic defects such as clusters of high-density Zr-rich particles as well as casting pores were identified. The Zr-rich particles as well as other primary intermetallic phases tended to agglomerate at the bottom of the ingots for all investigated alloys. The addition of RE increased the homogeneity of the microstructure in terms of spatial distribution as well as the global and local interconnectivities of intermetallic phases in the PMICC alloy. RC achieved a more homogeneous distribution of Zr-rich particles. Furthermore, RC led to changes of the solidification topology and increased the distance between the higher-density phases. Hot rolling reduced the fraction of pores formed during the casting process. However, pores were not detected in the ZK60 PMICC alloys after forming, while ZK60 + 1.5 wt% RE PMICC and RC showed the presence of voids that were not completely removed by hot rolling until the thickness was reduced about 60%.

Phase transformations in iron-carbon alloys doped with rare earth and transition metals

Iron-based alloys began to be used so long ago that today they are classified as classical materials, since these alloys have been studied in depth. The production of various products from steel and cast iron naturally takes the first place in terms of volume, since they have a valuable set of properties: a wide range of plasticity and strength, unique technological properties, which makes it possible to apply all technological operations to them - from simple casting into earth to complex pressure treatment processes. This combination of properties provides, first of all, the composition of iron-based alloys with the main alloying element – carbon. The serious disadvantage of ferrous alloys is their low level of corrosion properties. To eliminate this drawback, both steel and cast iron are alloyed with such metals as chromium, nickel, cobalt, etc. Naturally, this leads to an increase in the mass of finished products and structures. Therefore, the search for alloying elements to improve and optimize the composition of ferrous alloys is relevant today. On the other hand, the industry of Uzbekistan produces a sufficient amount of transition, rare earth metals. Thus, the task is to get added value from the production and processing of these non-ferrous metallurgy products. The analysis of the known literature data on this topic shows that research has been carried out on the use of various transition and rare earth metals for alloying ferrous alloys. However, the available scientific results do not allow to speak about systemic knowledge about the use of rare earth and/or transition metals as effective additives for steels and cast irons. The authors studied phase equilibria, determined the compositions of the phases and the reactions occurring in the systems, constructed phase diagrams, their isothermal sections, determined the structure of iron-based alloys with additions of rare-earth and transition metals with all structural components. The prospect of using the products of nonferrous metallurgy of Uzbekistan for the production of high-quality steels and cast irons is shown.

The Effect of Alloying on the Fractional Composition, Shape and Grain Size Distribution of the Structure Alloy GAP the Fe-Nd-B System

The magnetic and mechanical properties of the magnets Fe-Nd-B system are more dependent on the size and shape of the grain structure. The authors explored the effect of the neodymium content and the addition of transition metals (Mo, Co, Al) and rare-earth metals (Dy, Tb) on the formation of the structure alloy gas atomization powder the Fe-Nd-B system. It has been shown that doping enhances the formation of grain blocks with a radial gradient in the direction of grain growth. The alloying of a gas atomization powder alloy of the Fe-Nd-B system with rare-earth metals increases the anisotropy of the grain shape.