As a critical functional material in rapidly advancing scientific and technological fields,neodymium-iron-boron(NdFeB)magnets have witnessed continuous expansion of application domains and sustained year-on-year growth in global de-mand.NdFeB magnets are predominantly employed in permanent magnet motors across diverse industrial and consumer appli-cations.As these motors reach end-of-life,the resulting decommissioned units yield significant quantities of spent magnets-Posing dual challenges of environmental contamination and inefficient utilization of critical rare earth elements.Recycling these urban minerals can mitigate the rare earth resource imbalance,reduce associated environmental burdens,and support the es-tablishment of a circular magnet economy.This review systematically analyzes the technical characteristics of key remanufac-turing processes for high-performance NdFeB magnets derived from end-of-life sources,and critically evaluates current techno-logical limitations and emerging research priorities.
Cerium-based passivation films were deposited on Zn-5％Al coating,followed by stearic acid modification of the films deposited for varying durations to form a superhydrophobic coating.The microstructure of the cerium-based coating was examined using scanning electron microscopy(SEM),and surface roughness was assessed via laser confocal microscopy(LCM).The chemical composition of the coating was analyzed by energy dispersive spectroscopy(EDS)and X-ray photoelec-tron spectroscopy(XPS).Static contact angles were measured using a contact angle goniometer,and corrosion resistance was evaluated through electrochemical impedance spectroscopy(EIS)measurements performed on an electrochemical workstation.The results reveal that with the increasing of deposition time,the Ce content and film thickness on the Zn-5％Al coating in-creases continuously,accompanied by an increase in film thickness and a progressive enhancement of hydrophilicity.The ste-aric acid-modified film surface developed a micro-nanoscale rough structure,and the hydrophobicity increased progressively with prolonged passivation time.The modified film formed after 30 minutes of deposition achieved a water contact angle of 164°.The superhydrophobic surface is mainly composed of stearic acid,CeO2/Ce(OH)4,Ce2O3/Ce(OH)3,forming an air barrier that impedes liquid penetration into corrosive media.As the deposition time increases from 5 to 30 minutes,the corro-sion resistance shows a progressive enhancement.
The production of carbon monoxide(CO)through the electrocatalytic carbon dioxide reduction reaction(CO2RR)is of great significance for realizing the resource utilization of CO2,demonstrating favorable industrial potential.However,the development of electrocatalysts with high activity and selectivity remains a challenge.Rare earth metals have garnered extensive attention in the field of electrocatalysis due to their unique electronic structures and multivalent properties.In this study,a composite material(Pr6O11/g-C3N4)was synthesized through a multi-step process,featuring Pr6O11 nanopar-ticles supported on two-dimensional graphitic carbon nitride.The construction of the supported structure led to a decrease in the crystallinity of the Pr6O11 nanoparticles,resulting in a distorted lattice structure and altered electronic states of Pr.This re-sults in the Pr6O11/g-C3N4 catalyst exhibiting excellent CO selectivity during the electrocatalytic CO2RR.At a potential of-1.55 V(versus the reversible hydrogen electrode,RHE),the catalyst achieves a current density of 3.3 mA·cm-2 and a Faraday efficiency for CO of 80％,significantly outperforming the comparison samples.Additionally,the Pr6O11/g-C3N4 cata-lyst demonstrated a larger electrochemical active surface area and lower charge transfer resistance.This work provides new in-sights into the design and synthesis of efficient rare-earth-based electrocatalysts for the electroreduction of CO2.
To elucidate the influence of yttrium(Y)on the grain boundary diffusion behavior of dysprosium(Dy)in Nd-Fe-B and Nd-Ce-Fe-B sintered magnets,single-source(DyHx)and co-diffusion(DyHx+YHx)treatments were implemented via grain boundary diffusion processing.The study systematically evaluated how Y incorporation modulates the penetration depth,distribution uniformity,and magnetic isolation efficiency of Dy at grain boundaries across the two magnet systems.For the Nd-Ce-Fe-B magnet with 50％Ce(Mass fraction)substitution,the coercivity attains 13.58 kOe following synchronous grain boundary diffusion of YHx and DyHx,representing an enhancement of 1.55 kOe relative to magnets treated solely with DyHx.Microstructural and compositional analyses demonstrate that synchronous grain boundary diffusion markedly enhances the diffusivity of dysprosium(Dy)—A heavy rare earth element in Nd-Ce-Fe-B sintered magnets.This treatment promotes the formation of a continuous,chemically well-defined Dy-rich shell at intragranular depths beyond the primary grain boundaries,thereby substantially improving coercivity.However,the coercivity of Nd-Fe-B sintered magnets subjected to YHx/DyHx co-diffusion is lower than that achieved with DyHx-only diffusion treatment.
A solid-phase extraction(SPE)method utilizing an iminodiacetic acid-based chelating resin as the stationary phase was developed for the determination of 14 rare earth elements in seawater by inductively coupled plasma mass spectrome-try(ICP-MS).Adjust the pH value of water sample to the range of 8.5～9.0,followed by adsorption and enrichment of the target elements through solid-phase extraction.The detection limit of rare earth elements was 0.017 μg/L～0.024 μg/L,the relative standard deviation(RSD)of the method was 2.7％～4.8％,the recovery rates of spiking was 81.4％～105.0％.The proposed methodology is characterized by operational simplicity,high sensitivity,and efficiency,yielding highly satisfactory experimental results.
Doping of non-luminescent rare earth ions into luminescent rare earth complexes is an effective method to en-hance their photoluminescent properties.A series of Gd(Ⅲ)doped Eu(Ⅲ)complexes were synthesized by hydrothermal method with the ligand of 2,4,6-pyridyl tricarboxylic acid.The ratios of Gd(Ⅲ)to Eu(Ⅲ)are 0∶1.0,0.1∶0.9,0.2∶0.8,0.3∶0.7,0.4∶0.6,0.5∶0.5,0.6∶0.4,0.7∶0.3,0.8∶0.2,0.9∶0.1,respectively.The total contents of rare earth ions in the complexes were determined with EDTA standard solution by complexometric titration.And all the com-plexes were characterized by infrared spectroscopy.The fluorescence excitation spectra,emission spectra,fluorescence life-time and luminescent quantum yields of the complexes were tested.The effects of gadolinium doping on the luminescence per-formance of the europium complex were studied.The results show that the optimal excitation wavelength for this series of com-plexes is 295 nm.When the ratio of Gd(Ⅲ)to Eu(Ⅲ)is 0.6∶0.4,the fluorescence of the complex is strongest.Moreo-ver,even when the ratio of Gd(Ⅲ)to Eu(Ⅲ)changes from 0.1∶0.9 to 0.8∶0.2,the fluorescence intensity of Gd(Ⅲ)doped complexes is still stronger than that of pure Eu(Ⅲ)complexes.When the ratio of Gd(Ⅲ)to Eu(Ⅲ)is 0.6∶0.4,the doped complex has the longest fluorescence lifetime and the highest absolute quantum yield of luminescence.
Yttrium oxide powder has unique properties in magnetism electricity and light,and has broad application pros-pects in metallurgy,chemical industry and materials.This study systematically examine the effects of surfactant type and dos-age,reaction temperature,and yttrium nitrate solution concentration on the particle size of yttrium oxide.The results showed that under the condition of an ice bath at 0,lactic acid and polyethylene glycol were added at a mass ratio of mA∶m(yttrium nitrate)=1∶500 to 0.5 mol/L yttrium nitrate solution,respectively,the pH was adjusted to neutral by using diluted 10-fold ammonia,and dried and calcined after aging at room temperature for 1 h.Yttrium oxide powders with D50=12.63 μm could be obtained,and the morphology and size distribution were relatively homogeneous,with yttrium oxide averaging once the av-erage particle size of yttrium oxide was 20 nm～30 nm.
In response to the limitations of traditional near-infrared(NIR)reflective materials,which exhibit monotonous coloration and induce object heating due to NIR radiation,rare earth elements have emerged as a research focus for developing high-reflectivity,multicolored,and environmentally friendly reflective materials due to their unique optical properties.This study highlights mainly expounds the synthesis methods,crystal structure control strategies,performance characteristics,and application status of rare earth composite reflective materials.The principal preparation techniques include the solid-phase methods,sol-gel methods,and self-propagating combustion.Among these,the sol-gel method is widely utilized due to its mo-lecular-level homogeneity and structural controllability.Through doping with rare earth ions,the energy band structure and lat-tice distortion of materials can be effectively modulated to achieve high reflectivity(up to 98％)within the NIR band wave-length range(700 nm～2500 nm)as well as color diversity.Furthermore,this study outlines future research prospects for rare earth composite reflective materials.
Light weight hydrogen storage alloys represented by Mg-RE-based metal hydrides have shown broad application prospects in hydrogen energy storage and new energy applications due to their light weight abundant resources and potential high thermal conductivity.The Mg90Ni5(La,Ce)5 alloy ingots were prepared via induction suspension melting.After mechani-cal crushing and sieving,powders with particle sizes ranging from approximately 50 μm to 600 μm were obtained.Subsequent-ly,the powders were compacted into pelletized samples to investigate the effect of particle size on the thermal conductivity of the samples was evaluated using the TC3100 hot wire method calorimeter and the LFA467 laser flash method apparatus.The microstructures of the powders and alloy specimens were characterized by scanning electron microscopy.Results indicated that in the powder state,the thermal conductivity of the alloy powder with a peak particle size of 173 μm was significantly higher than that of the 56 μm powder.Under the tablet-pressing condition,the thermal conductivity of the 173 μm alloy pellet is 18.88 W/(m·K),whereas that of the 56 μm alloy pellet is 9.11 W/(m·K).At 298 K,the thermal conductivity of the 173 μm alloy powder is 0.18 W/(m·K),whereas that of the 56 μm alloy powder is 0.14 W/(m·K).Regardless of whether the samples were in powder or compact form,the thermal conductivity increased with rising temperature at a given particle size.Upon consolidation into pellets,the thermal conductivity of the Mg90Ni5(La,Ce)5 alloy powder is significantly enhanced.When the temperature reaches 373 K,the thermal conductivity of the 173 μm alloy powder is only 0.20 W/(m·K).How-ever,after consolidation into pellets,its thermal conductivity increases to 20.26 W/(m·K).
The molten salt electrolysis method is an important process for producing rare earth metals,and the electrolytic cell is its core equipment.The research on multiphysics simulation of rare earth electrolysis cell involves many disciplines such as metallurgy,physics and mathematics.In recent years,the combination of multiphysics simulation and numerical simulation of rare earth electrolytic cell has become an important means of optimizing the design of electrolysis cell and auxiliary produc-tion process control.This article summarizes four physical fields of rare earth electrolysis cells:electric field,magnetic field,flow field,and temperature field.Discuss and analyze the current research status of different physical fields and their impact on the rare earth electrolysis process.Multiple physical fields within the rare earth electrolytic cell exert individual effects while simultaneously interacting through coupling mechanisms.These interactions directly influence energy consumption during electrolysis,current efficiency,and the operational lifespan of the electrolytic cell.However,to date,no study has achieved a fully coupled numerical solution that comprehensively integrates these multiphysics phenomena.Multiphysics coupled simula-tion analysis of rare earth electrolytic cells plays a pivotal role in optimizing the design of physical fields within these systems and advancing the development of novel cell configurations,representing a critical pathway toward future technological pro-gress.
The 15Cr5MoVRE alloy,a commonly used material for oil well pipe,incorporates alloying elements including Cr,Mo,V,and rare earth elements(RE)to enhance its corrosion resistance in harsh environments and extend service life.In this paper,the evolution law of corrosion products on 15Cr5MoVRE well pipe was studied by indoor solution immersion method.The surface macroscopic morphology of the corrosion product film was observed by digital camera,the microscopic morphology of the corrosion product film was observed by field emission scanning electron microscope(SEM),and the struc-ture and composition of the corrosion product were analyzed by X-ray diffractometer(XRD)and EDS.The average corrosion rate was calculated by the weight loss method.The results show that the average thickness of the corrosion product film increa-ses progressively with prolonged exposure to the corrosive environment.The corrosion products primarily consist of CaCO3 and Fe3O4,Cr2O3 appeared after 120 h of corrosion.Over extended corrosion periods,CaCO3 content was gradually decreased,Fe3O4 and Cr2O3 content gradually increased;After 240 h of corrosion,continuous dense Fe3O4 and Cr2O3 corrosion products cover the whole surface of the matrix,playing a mechanical role between the solution and the matrix;The corrosion rates of test steel of 120 h,240 h,240 h and 360 h and 720 h were 0.0574 mm/a,0.0646 mm/a,0.0632 mm/a and 0.0527 mm/a,re-spectively.The corrosion rate increases first and then decreases,when corroded for 240 h.Its average corrosion rate reaches the maximum value.
Rare earth elements exhibit unique physical and chemical properties due to their special electronic structure and are widely employed in applications such as sensors.This paper investigated the impact of nickel doping on the phase,chemical state,and morphological properties of ceria.A comparison of the sensor responses based on cerium oxide-based sen-sitive materials before and after doping to various organic compounds and hydrogen.This study found that NiO doping promotes the formation of oxygen vacancies in CeO2 and enhances the concentration of cerium ions in lower valence states.The sensitivi-ty of CeO2 doped with 1.0％NiO to organic compounds is significantly enhanced,and its response to acetone is markedly higher than that to other organic compounds.Compared with undoped CeO2-based sensors,the response intensity to acetone is approximately four times higher,and the sensor also exhibits excellent response characteristics toward trace amounts of hydro-gen.Research results indicate that nickel doping can effectively increase the concentration of oxygen vacancies in CeO2,thereby enhancing the material's response characteristics to specific gases.
The most distinctive feature of rare-earth β-diketone fluorescent probes lies in the relatively high absorption co-efficient and efficient energy transfer of the ligands to ions like Eu3+and Tb3+.However,there are few reports on using bis-β-diketone ligands themselves as fluorescent probes.A new fluorescent probe,bis-β-diketone ligand fluorescent probe-1,1-thio-phen-2,5-bis(9-anthracenyl)-1,3-propanedione(E),was designed and synthesized by using anthracene as fluorophore and dimethyl 2,5-thienediarboxylate as raw material through Claisen ester condensation reaction.The structure of the probe was confirmed by IR,1HNMR,and XPS.The recognition properties of bis-β-diketone E for rare earth and metal ions were system-atically studied.The results revealed that bis-β-diketone E has significant fluorescence quenching effects on Y3+and Al3+,with detection limits of 2.29×10-6 mol/L and 5.5×10-7 mol/L,respectively.The ability of bis-β-diketone E to identify Al3+in water samples and expanding agents as a fluorescent probe was also investigated,providing a new approach for food detection.
This article systematically summarizes the research progress on chemical mechanical polishing of shallow trench isolation(STI),inter level dielectric(ILD)and metal layers in the process of integrated circuit fabrication.In the shallow trench isolation(STI)CMP processes,the materials removal rate is relative to the Ce3+concentrations on the surface of cerium oxide,the higher Ce3+concentration leads to the higher polishing efficiencies.In the chemical mechanical polishing of dielectric materials,Cook's elastic contact theory offers a well-substantiated explanation for the material removal mecha-nism.During the chemical mechanical polishing process of metal thin films,the material removal mechanism involves the oxi-dation of the metal surface to form the corresponding oxide,followed by mechanical abrasion to remove the material.
In recent years,China has made substantial progress in the exploration of ion-adsorption rare earth ores.Key advances include the identification of such deposits within weathered crusts developed on metamorphic bedrock,as well as the documented co-occurrence of light and heavy rare earth ores in granite-derived regolith.District A in southern China displays extensive geochemical anomalies in the rare earth elements lanthanum(La)and yttrium(Y),which have led to the identifi-cation of several light rare earth element ores.To assess whether light and heavy rare earth element(REE)fractionation oc-curs in ion-adsorption REE ores of District A in southern China,systematic sampling was carried out across weathering profiles developed on granite and gneiss bedrock in both district A and district B.Subsequent geochemical analysis characterized the vertical distribution patterns of REEs within these profiles.Research findings indicate the co-occurrence of ion-adsorption light rare earth element(LREE)and heavy rare earth element(HREE)mineralization within granite-derived weathering profiles at both study sites.A systematic vertical shift from LREE-enriched to HREE-enriched zones along individual regolith profiles demonstrates pronounced geochemical stratification between light and heavy rare earth elements.Within the study region,the identified heavy rare earth element(HREE)ores are predominantly enriched in yttrium,lanthanum,neodymium,gadolini-um,and dysprosium oxides-Characterizing a high-yttrium,low-europium HREE mineralization signature.This finding refines the regional rare earth exploration paradigm,with particular implications for the targeting of ion-adsorption heavy rare earth ores.
In order to expand the process window of press hardening steel 1500HS,an experimental study was conducted on the addition of rare earth elements to this alloy,based on prior statistical analysis of literature regarding rare earth applica-tions in steel.In this study,a vacuum induction furnace was used to melt hot-formed steels with and without a specific Ce con-tent.Subsequently,phase transformations of the specimens were comparatively analyzed using a Gleeble-3800 thermomechani-cal simulator and metallographic analysis techniques.The results show that Ce can effectively improve the stability of austen-ite,inhibitive the ferrite transformation,and reduce the ferrite transformation temperature by 28 ℃～34 ℃.The influence of Ce on the bainite and martensite transformation temperatures in press hardening steel is not significant.However,it reduces the martensite critical cooling rate from 30 ℃/s to 20 ℃/s.The addition of Ce can effectively increase the process window press hardening stamping process.Under the experimental conditions,the processing window for stamping and mold closure of press hardening steel can be reduced by 45 ℃,which is beneficial for production in lower ambient temperatures or for thin-gauge products.
The reaction rate of oxygen reduction reaction(ORR)in solid oxide fuel cells(SOFCs)critically influence their overall performance;Pr2NiO4+δ,a rare-earth nickelate,with high promise as a cathode material,exhibits an incompletely resolved surface ORR mechanism-primarily owing to challenges including intrinsic material decomposition under operating conditions and inherent limitations in probing reaction pathways within conventional porous electrode architectures.Thin-film model systems thus provide a well-controlled platform for mechanistic investigation of the fundamental ORR processes.This study investigated the oxygen reduction reaction(ORR)kinetics of Pr2NiO4+δ(PNO)thin films,synthesized via pulsed laser deposition(PLD)on Y2O3-stabilized ZrO2(YSZ)single-crystal substrates.Electrochemical impedance spectroscopy(EIS)analysis showed that the PNO thin films exhibited excellent electrochemical performance within the temperature range of 550 ℃～670 ℃,with the area-specific resistance(ASR)significantly decreasing as the temperature increased,following the typical Arrhenius behavior.The relationship between ASR and oxygen partial pressure was also measured,and the relationship between chemical capacitance(Cchem)and oxygen vacancies was derived.
Carbon monoxide(CO)is one of the primary air pollutants generated during industrial production.As envi-ronmental regulations in China continue to tighten and emission standards become increasingly stringent,the effective removal of CO has gained significant importance.Catalytic oxidation based on perovskite oxides(ABO3)represents a highly promising CO removal technology,with the development of high-performance perovskite catalysts being a critical factor in enhancing its efficiency.Rare-earth elements,owing to their unique 4f electronic configuration,moderate valence states,and ionic radii,play a critical role in modulating the CO catalytic oxidation performance of perovskite materials and modulating the redox prop-erties of B-site transition metals,thereby significantly influencing the CO catalytic oxidation performance.This review summa-rizes the common preparation methods of rare earth-based perovskite oxide materials and the mechanisms for regulating catalyt-ic performance of rare-earth-based perovskites through strategies including A/B-site doping,surface engineering,and morphol-ogy control,while analyzing the intrinsic correlations between rare-earth elements and the material's electronic structure,oxy-gen mobility,and stability.Furthermore,to address the critical challenge of sulfur-induced catalyst deactivation in practical applications,this work discusses the interaction mechanisms between active components and sulfur species.Thereby offering theoretical insights and technical guidance for the development of advanced rare earth-based perovskite catalytic materials that exhibit both high catalytic activity and strong resistance to sulfur poisoning.
Polyurethane rigid foam was prepared by prepolymerization method,and composited with CeO2 of different par-ticle sizes to prepare cerium oxide/polyurethane rigid foam composites,and the influence of CeO2 particle size on the proper-ties of CeO2-based polyurethane rigid foam composites was investigated.When the mass fraction of cerium oxide in polyure-thane rigid foam was 16％,the thermal stability and hardness of the composites showed an increasing trend with the decrease of cerium oxide particle size.The cerium oxide nanomodified polyurethane showed enhanced wear resistance and a porosity of 48.7％.To evaluate the application performance of the composite materials,they were applied in the polishing process of liquid crystal glass a machine test was conducted using a 1 μm cerium oxide polishing slurry.The results showed that the polyure-thane rigid foam composite containing 5 μm cerium oxide achieved the highest polishing efficiency,but was prone to causing surface scratches.In contrast,the composite with 1 μm cerium oxide exhibited moderate polishing efficiency and yielded an approximate pass rate of 80％.
