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Due to the strong reducibility and chemical activity of rare earths, the diffusion behavior and secondary oxidation of rare earths in the steel liquid will also have a significant impact on the modified products when rare earths are added to bearing steel, resulting in poor control of distribution behavior. Therefore, this paper studies the influence of time factors on the evolution of rare earth inclusions. The inclusion evolution behavior at different times when the bearing steel was treated with rare earths and subjected to secondary oxidation was simulated at 1873 K (1600 °C). At a cerium content of 0.012% in steel and a secondary oxidation of 0.0025%, the cerium content in steel and the total oxygen (T.O.) content in steel were determined at the 30 s, 3 min, 5 min, and 7 min after the addition and the inclusions were characterized by automatic scanning electron microscopy. The results demonstrated the formation of a cerium-enriched zone after the addition of the cerium alloy to the steel. As time progressed, a considerable number of inclusions were generated in the cerium-enriched zone, which subsequently disappeared. The trend in the composition of the inclusions can be described as Al2O3 → Ce2O2S + CeS → Ce2O2S. The final composition of the inclusions matches the thermodynamic phase diagram. Following the addition of the transient oxidant Fe2O3 to the molten steel, an oxygen-enriched zone was formed. As time progressed, a considerable number of inclusions were generated in the oxygen-enriched zone and subsequently disappeared. The trend of inclusions composition was as follows: Ce2O3 + CeAlO3 + Al2O3 → Ce2O3 + CeAlO3 → Ce2O2S + CeAlO3. The final inclusion composition coincides with the thermodynamic phase diagram. [ABSTRACT FROM AUTHOR]

Consumption of rare-earth metal (REM) oxides, such as cerium and lanthanum, is significantly lower than their production. This discrepancy is attributed to the complex extraction of all REMs, where the share of cerium is approximately 40%. This article proposes a method for processing REM oxides for their use as master alloys in ferrous metallurgy products. REMs, in the form of modifiers for steels and alloys, are widely used. However, despite their wide usage, owing to the complexity of the REM production technology, they tend to have a high market value. This study explores the preparation of a cerium carbide (CeC2) master alloy for the modification of steels and cast irons. The proposed method aims to reduce the cost of the alloying process and simultaneously increase the demand for REM oxides. Using a high-temperature synthesis process, CeC2 was obtained for the modification of steel and cast iron. For this purpose, cerium dioxide (CeO2), graphite (C), and ARMCO-iron (Fe) were mixed in a specific percentage ratio by weight: 5.4% C, 19.5% CeO2, and 75.1% Fe. Following this, the reaction mixture was heated in a furnace to a temperature of 1650°C and held for 30 min, with a residual pressure in the furnace of 10–1 mbar. The synthesis was performed in the temperature range of 1300–1650°C, with the highest reaction rate of at a temperature of 1520°C. Both elemental and X-ray diffraction analyses indicated that CeO2 was the end product of the synthesis process. The master alloy does not undergo hydrolysis because CeC2 is synthesized in the liquid phase of iron. It has been established that the technology for producing a cerium carbide alloy involving high-temperature heating in a resistive furnace, enables the production of a material with reproducible properties. [ABSTRACT FROM AUTHOR]

In the present work, magnesium cerium binary alloy with varying cerium content (0.5 %, 1 %, 1.5 % and 2 %) has been produced by stir casting and microstructure, mechanical properties and wear characteristics have been investigated. From the microstructural observations, development of intermetallic at the grain boundaries was observed with higher cerium content. X‐ray diffraction analysis of the produced samples indicated peaks corresponding to solid solution grains of magnesium and cerium and Mg12C intermetallic. Hardness measurements showed improved values for the alloy with 1.5 % and 2 % cerium. Tensile test results demonstrated higher strength at the cost of losing ductility with the increased cerium content. Enhanced mechanical performance in the alloys with higher cerium can be attributed to the presence of intermetallics at the grain boundaries. Increased wear resistance as reflected from the lower frictional force and wear has been observed for the alloy with 2 % cerium. [ABSTRACT FROM AUTHOR]

Magnesium-based alloys hold potential for medical applications, but face challenges like rapid bioresorption and limited mechanical strength during early bone healing. In our study, we present a novel Mg–Zn–Zr–Ce alloy with low cerium content (up to 0.1 wt.% Ce) processed using two severe plastic deformation (SPD) techniques. Through an innovative combination of multiaxial forging and multipass rolling, we have achieved a fine-grained structure with an average grain size of the primary α-Mg phase of 1.0 μm. This refined microstructure exhibits improved mechanical properties, including a substantial increase in yield strength (σYS) from 130 to 240 MPa, while preserving ductility. The alloy's composition includes α-Mg grains, cerium and zinc hydrides, and intermetallic phases with cerium and zinc elements. Tensile testing of the fine-grained alloy demonstrates an enhancement in yield strength (σYS) to 250 MPa, marking a 2.8-fold improvement over the conventional state (σYS = 90 MPa), with a modest 2-fold reduction in ductility. Crucially, electrochemical tests conducted in physiological solutions highlight substantial advancements in corrosion resistance. The corrosion current was reduced from 14 to 2 μA/cm2, while polarization resistance decreased from 3.1 to 8.1 kΩ∙cm2, underlining the alloy's enhanced resistance to biodegradation. Our results show that the novel Mg–Zn–Zr–Ce alloy, after combined SPD, demonstrates mitigated bioresorption and enhanced mechanical properties. Our findings highlight the fact that the introduction of this innovative alloy and the application of SPD represent significant steps towards addressing the limitations of magnesium-based alloys for medical implants, offering potential improvements in safety and effectiveness. [ABSTRACT FROM AUTHOR]

The electrochemical reduction of pelleted heterophase powder Pd-Nd2O3-CeO2 mixtures was studied in molten LiCl-Li2O (1–1.5 wt%) at 650 °C. The influence of the composition of the mixture, as well as electrochemical factors—i.e., the amount of electricity passed and the cathode potential during electrolysis—were considered. It was found that in the presence of metallic palladium, neodymium and cerium oxides are reduced by lithium released at the cathode and form intermetallic compounds of different compositions. At potentials more positive than the formation of a phase based on liquid lithium at 0.5–0.8 V, CePd3 and NdPd3 intermetallic compounds are present in the reduced product. At potentials close to the formation of liquid lithium, a whole spectrum of intermetallic compounds is synthesized: CePd, NdPd, Ce3Pd4, and Nd3Pd4. The mechanisms of formation of palladium alloys with neodymium and cerium are proposed and considered. The degree of the reduction of lanthanide oxides was calculated from the data on the concentration of residual oxygen in the reduced product. [ABSTRACT FROM AUTHOR]

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A modified cerium seal PEO pretreatment was developed on 2A14 alloy and combined with an epoxy coating (EP) to form a duplex coating system. The PEO coating was effectively sealed by cerium hydroxides and oxides, and also acted as a controlled release vessel for the cerium salt corrosion inhibitor, and significantly improved the adhesive strength of the EP. The results of electrochemical tests and immersion experiments show that the coating system pretreated with the modified cerium seal PEO exhibits excellent long-term corrosion resistance and active protection. This is attributed to the physical barrier of insoluble cerium-based compounds and sensitive pH-responsive deposition. • A modified Ce-sealed PEO pretreatment was developed for use as an intermediate layer in coating systems. • The PEO coating is effectively sealed and used as a container to store Ce salt inhibitors. • Modified Ce-sealed PEO pretreatment significantly improves the physical barrier effect of the overall coating system. • Ce-sealed PEO coating systems provide effective active corrosion protection for substrates in the event of damage. [ABSTRACT FROM AUTHOR]

Cerium–lanthanum alloys are the main component of nickel–metal hydride batteries, and they are thus an important material in the green-energy industry. However, these alloys have very strong chemical activity, and their surfaces are easily oxidized, leading to great difficulties in their application. To improve the corrosion resistance of cerium–lanthanum alloys, it is necessary to obtain a nanoscale surface with low roughness. However, these alloys can easily succumb to spontaneous combustion during machining. Currently, to inhibit the occurrence of fire, machining of this alloy in ambient air needs to be conducted at very low cutting speeds while spraying the workpiece with a large amount of cutting fluid. However, this is inefficient, and only a very limited range of parameters can be optimized at low cutting speeds; this restricts the optimization of other cutting parameters. To achieve ultraprecision machining of cerium–lanthanum alloys, in this work, an auxiliary machining device was developed, and its effectiveness was verified. The results show that the developed device can improve the cutting speed and obtain a machined surface with low roughness. The device can also improve the machining efficiency and completely prevent the occurrence of spontaneous combustion. It was found that the formation of a build-up of swarf on the cutting tool is eliminated with high-speed cutting, and the surface roughness (Sa) can reach 5.64 nm within the selected parameters. Finally, the oxidation processes of the cerium–lanthanum alloy and its swarf were studied, and the process of the generation of oxidative products in the swarf was elucidated. The results revealed that most of the intermediate oxidative products in the swarf were Ce3+, there were major oxygen vacancies in the swarf, and the final oxidative product was Ce4+. HIGHLIGHTS: • An assisted machining device was developed for the inhibition of the oxidation and fire during the machining process. • The auxiliary machining device can increase the spindle speed and eliminate the oxidation of swarf. • The nanoscale machined surface can be stably obtained by increasing the spindle speed for the cerium–lanthanum alloy. [ABSTRACT FROM AUTHOR]

In this study, using the ultra-fine molybdenum-27.5 wt% copper-(0–5) wt% tungsten-1.75 wt% nickel-0.75 wt% iron-0.5 wt% cerium dioxide composite powders as experimental materials, molybdenum‑copper‑tungsten‑nickel‑iron‑cerium dioxide blocks were obtained through low-temperature powder sintering. All alloy samples owned high relative densities (98.1 ± 0.05–98.9 ± 0.05%). Besides, the formations of molybdenum‑tungsten and γ-(copper, nickel, iron) solid solutions guaranteed the sample owned good comprehensive strength. Sintered block with the highest tension strength, compression strength, bending strength and hardness was prepared through introducing 2.5 wt% tungsten, which were 586 ± 4 MPa, 2928 ± 11 MPa, 1554 ± 5 MPa and 305 ± 3 HV respectively. However, the presences of iron, nickel and cerium dioxide affected the conductivities, and therefore, electric conductivities of the samples were 33.08 ± 0.02–33.47 ± 0.02 %IACS. • Ultra-fine molybdenum-copper‑tungsten‑nickel‑iron‑cerium dioxide composite powder was obtained by a two-stage reduction method. • High performance molybdenum-copper‑tungsten‑nickel‑iron‑cerium dioxide alloys with additions of tungsten were prepared. • Molybdenum-27.5 wt% copper-2.5 wt% tungsten-1.75 wt% nickel-0.75 wt% iron-0.5 wt% cerium dioxide alloy had good overall performances. [ABSTRACT FROM AUTHOR]

In this research work, the analysis of mechanical and metallurgical properties of AZ91D + XCe + XLi cast magnesium (Mg) alloys in adding cerium (Ce) and lithium (Li), where X can be varied. The destructive tests viz. mechanical test, tensile strength test, and microhardness test are used to investigate mechanical properties of AZ91D alloy in adding various weight percentages viz. 0.5, 1, 2, of Ce and Li. This result of this present investigation reveals that there will be refinement of grain size on AZ91D alloy in adding Ce and Li. The formation of second phase Al2Ce that has superior melting point, changes the distribution of the phase Mg17Al12 from a continuous network morphological transition to a tiny and dispersive distribution along the grain boundary. Furthermore, adding Li to the AZ91D magnesium alloy lowers the corrosion current density in a 3.5 percent NaCl solution, improving the alloy's corrosion resistance. The results show that the AZ91D magnesium alloy, which contains 0.5 percent Ce + 1.0wt.%, outperforms other magnesium alloys. [ABSTRACT FROM AUTHOR]

The casting alloy & process selector, I Casting Alloy Data Search (CADS) i , is located on the AFS website, www.afsinc.org under the " I Designers & Buyers" i tab, or can be accessed directly at www.metalcastingvirtuallibrary.net/cads/cads.aspx. AFS directly funds research projects from the allocation of a portion of annual dues paid by AFS Corporate Membership. Casting Alloy Data Search (CADS) AFS through AMC/DLA has developed a very effective web-based tool called Casting Alloy Data Search (CADS) for design engineers and ICME professionals, which has been used for over five years by the foundry industry and is accessible through the AFS website. AFS Information Services Casting Process and Alloy Assistance The American Foundry Society website provides tools to assist casting design engineers in selecting the best casting process for a potential component and also provides casting alloy property data on many commonly used alloys. [Extracted from the article]

Purpose: This paper aims to analyze the effect of cerium addition on the microstructure and the mechanical properties of Tin-Silver-Copper (SAC) alloy. The mechanical properties and refined microstructure of a solder joint are vital for the reliability and performance of electronics. SAC305 alloys are potential choices to use as lead-free solders because of their good properties as compared to the conventional Tin-Lead solder alloys. However, the presence of bulk intermetallic compounds (IMCs) in the microstructure of SAC305 alloys affects their overall performance. Therefore, addition of cerium restrains the growth of IMCs and refines the microstructure, hence improving the mechanical performance. Design/methodology/approach: SAC305 alloy is doped with various composition of xCerium (x = 0.15, 0.35, 0.55, 0.75, 0.95) % by weight. Pure elements in powdered form were melted in the presence of argon with periodic stirring to ensure a uniform melted alloy. The molten alloy is then poured into a pre-heated die to obtain a tensile specimen. The yield strength and universal tensile strength were determined using a fixed strain rate of 10 mm per minute or 0.1667 mm s^(−1). The IMCs are identified using X-ray diffraction, whereas the elemental phase composition and microstructure evolution are, respectively, examined by using electron dispersive spectroscopy and scanning electron microscopy. Findings: Improvement in the microstructure and mechanical properties is observed with 0.15% of cerium additions. The tensile test also showed that SAC305-0.15% cerium exhibits more stress-bearing capacity than other compositions. The 0.75% cerium doped alloy indicated some improvement because of a decrease in fracture dislocation regions, but microstructure refinement and the arrangement of IMCs are not those of 0.15% Ce. Different phases of Cu_6 Sn_5, Ag_3 Sn and CeSn_3 and ß-Sn are identified. Therefore, the addition of cerium in lower concentrations and presence of Ce-Sn IMCs improved the grain boundary structure and resulted refinement in the microstructure of the alloy, as well as an enhancement in the mechanical properties. Originality/value: Characterization of microstructure and evaluation of mechanical properties are carried out to investigate the different composition of SAC305-xCerium alloys. Finally, an optimized cerium composition is selected for solder joint in electronics. [ABSTRACT FROM AUTHOR]

We report memristor behavior in a macroscopic bulk Kondo insulator Ce 3Bi 4Pt 3 below 10 K. The ac current and voltage relation characteristic of memristors, pinched hysteresis loops which merge into a single line at high frequency, are systematically observed. A standard lock-in technique is used to probe the origin of this exotic behavior which cannot be explained solely by a static resistance drop arising from joule heating. Rather the response appears to be associated with the formation of dynamic thermal impedance in the dissipative regime. © 2012 American Institute of Physics.

The effects of the addition of rare earth cerium on the cast microstructure and mechanical properties of 2024-T6 aluminum alloy were investigated in this work. The specimens for room-temperature tensile tests were prepared with a T6 heat treatment. Experimental results indicated that the cerium modified alloys showed refined grains, higher hardness, and strength values at room temperature. The hardness and the strength of the cerium modified alloys initially increased and then decreased as the cerium content increased. The maximum tensile strength was obtained at the 0.6 wt.% cerium modified 2024 aluminum alloy. This was improved from 464 MPa to 612 MPa. Simultaneous increases in the tensile strength and hardness were proposed to result from the refined α-aluminum dendrites, the formation of aluminum-rare earth intermetallic compounds at the grain boundaries and the grains, the more homogeneously distributed nano-scale S precipitates, and the smaller T diffusion phase. [ABSTRACT FROM AUTHOR]

Cerium conversion coatings were explored as an alternative to chromate conversion coatings for corrosion protection of aluminium alloy 7075-T6. Conversion coatings were formed in a conversion bath of 0.05 M cerium salt and 0.25 M hydrogen peroxide at room temperature. Various cerium salts were used: Ce(III) acetate, Ce(III) nitrate and Ce(III) chloride. The conversion process from Ce3+ to Ce4+ was followed by UV-VIS spectroscopy. The conversion of cerium coatings on alloy surface was monitored by measuring open circuit potential. To investigate the corrosion properties of uncoated and coated samples, the linear polarization and electrochemical potentiodynamic curves were recorded in 0.1 M NaCl. Additionally, salt spray chamber testing was carried out. Samples were characterized by scanning electron microscopy. Results revealed that the cerium conversion and corrosion resistance were dependent on the type of cerium salt and conversion time in the conversion bath. The most compact and uniform cerium conversion coatings were produced from solution of cerium(III) acetate, but better protection was obtained in nitrate and, especially, chloride solutions due to thicker coatings. [ABSTRACT FROM AUTHOR]

The poor corrosion/wear resistance of Mg alloy seriously limits its industrial application. Graphene-based anti-corrosion coatings show the excellent imperviousness, but they can provide the additional cathodic sites for Mg alloys, which accelerates the galvanic corrosion behaviors near the interfaces. A novel design of cerium-based intermediate layer (Ce(Ⅳ)) is reported in this study, which exhibits a synergistic effect of hydrogen/ionic bond on the graphene oxide (GO)/polyvinyl alcohol (PVA) biomimetic coating. It overcomes the problems of galvanic corrosion and low interfacial adhesion between Mg substrate and hybrid coating through a prominent barrier effect. Furthermore, the GO/PVA coating with "bricks and mortar" structure effectively blocks the permeation of electrolyte due to the reduced porosity and enhanced densification. The corrosion rate of Ce(Ⅳ)/GO/PVA coating is 11 and 19 times lower than bare Mg alloy and single GO/PVA film, respectively. The wear rate of GO/PVA and Ce(Ⅳ)/GO/PVA samples is decreased by 98.8% and 97.6%, which is ascribed to the high hardness and lubrication of GO sheets. Moreover, the relatively interlayer slipping between GO sheets can lubricate the sliding process. Compared with GO/PVA, the slightly decreased wear resistance of Ce(Ⅳ)/GO/PVA coating is resulted from the enhanced shear force. Image 1 [ABSTRACT FROM AUTHOR]

The effect of cerium on inclusions in an ultra-low-carbon Al-killed steel was studied at 1873 K (1600 °C) using laboratory experiments. The content of cerium in the steel varied from 0 to 0.028 wt pct. The contents of the total oxygen (T.O), total nitrogen (T.N), total sulfur (T.S), total cerium (T.Ce) and dissolved aluminum ([Al]) in the steel samples 1, 5, 10 and 30 minutes after adding cerium were measured, and inclusions were characterized using an automatic scanning electron microscope. It was found that a cerium-concentrated zone formed after the cerium alloy was added to the molten steel. Many inclusions were generated in the cerium-concentrated zone and then disappeared with the decrease of the cerium content. The variation of the inclusion composition was Al2O3 → CeAlO3 → Ce2O2S → Ce2O2S + CeS with the increasing cerium content in the steel, which agreed well with the thermodynamic analysis. The value of T.Ce/T.O was able to evaluate and predict the type of inclusions. A prediction model of the composition of inclusions was established based on thermodynamic calculation and mass balance and was validated by experimental data. When the value of T.Ce/(T.S + T.O) was ≥ 4.4, the average composition of inclusions changed little since most inclusions were fully modified. [ABSTRACT FROM AUTHOR]

Rare-earth metals create unique opportunities in improving properties of aluminum alloys. For over a century, there have been attempts to explore cerium for aluminum alloying, emphasizing advantages it exhibits among rare earths. This review covers laboratory and industrial efforts of applying cerium for a purpose of developing aluminum alloys with superior properties. The binary Al–Ce, ternary Al–Ce–X and higher-order phase systems are reviewed with a focus on the aluminum-rich sections. The role of cerium in forming stable, high-melting-point compounds, improving strength and thermal stability is analyzed along with its function as a grain refiner in the aluminum melt, the eutectic modifier, as de-gasifying and de-slagging agent through its reaction with gas and liquid impurities. In addition to conventional alloys with cerium as a minor and major ingredient also amorphous alloys along with aluminum matrix nanocomposites, exploring cerium oxide as reinforcement, are assessed. The role of cerium in bulk alloying is expanded to surface engineering solutions enhancing aluminum wear and corrosion resistance. Efforts of cerium recovery from parts after end of service life and alloy design for a recycling friendly world are discussed to minimize losses and prevent contamination of material supply chain in modern manufacturing. [ABSTRACT FROM AUTHOR]

Electron-spin-resonance (ESR) measurements performed on the filled skutterudite system Ce1-x Ybx Fe4 P12 (x≲0.003) unequivocally reveal the coexistence of two Yb3+ resonances associated with sites of considerably different occupations and temperature behaviors. Detailed analysis of the ESR data suggests a scenario where the fraction of oversized (Fe2 P3) 4 cages that host Yb ions are filled with a low occupation of on-center Yb3+ sites and a highly occupied T -dependent distribution of off-center Yb3+ sites. Analysis of the Y 171 b3+ (I=1/2) isotope hyperfine splittings reveal that these two sites are associated with a low (∼1 GHz) and a high (≲ 15 GHz) rattling frequency, respectively. Our findings introduce Yb3+ in Th symmetry systems and use the Yb3+ ESR as a sensitive microscopic probe to investigate the Yb3+ ions dynamics. © 2009 The American Physical Society.

Electron-spin-resonance (ESR) measurements performed on the filled skutterudite system Ce1-x Ybx Fe4 P12 (x≲0.003) unequivocally reveal the coexistence of two Yb3+ resonances associated with sites of considerably different occupations and temperature behaviors. Detailed analysis of the ESR data suggests a scenario where the fraction of oversized (Fe2 P3) 4 cages that host Yb ions are filled with a low occupation of on-center Yb3+ sites and a highly occupied T -dependent distribution of off-center Yb3+ sites. Analysis of the Y 171 b3+ (I=1/2) isotope hyperfine splittings reveal that these two sites are associated with a low (∼1 GHz) and a high (≲ 15 GHz) rattling frequency, respectively. Our findings introduce Yb3+ in Th symmetry systems and use the Yb3+ ESR as a sensitive microscopic probe to investigate the Yb3+ ions dynamics. © 2009 The American Physical Society.

We show using neutron diffraction that the magnetic structure of CeRhIn4.85 Hg0.15 is characterized by a commensurate propagation vector (1/2,1/2,1/2). This is different from the magnetic structure in the parent compound CeRhIn5, which orders with an incommensurate propagation vector (1/2,1/2,0.297). The special relation between the commensurate magnetic mode and unconventional superconductivity has been shown previously for this class of heavy fermion superconductors. This work provides further evidence for the ubiquity of this antiferromagnetic mode. © 2009 The American Physical Society.

We report measurements of the de Haas-van Alphen effect on a series of compounds, LaMIn5 (M=Co,Rh,Ir). The results show that each of the Co and Ir Fermi surfaces (FSs) exhibits some portions that are two dimensional and some portions that are three dimensional. The most two-dimensional character is exhibited in LaCoIn5, less two-dimensional behavior is seen in LaIrIn5, and no part of Fermi surface of LaRhIn5 is found to have a two-dimensional character. Thus the two dimensionality of portions of the FSs is largely determined by the d character of the energy bands while all of the effective masses remain ≤1.2. This fact has implications for the causes of the heavy fermion nature of superconductivity and magnetism in the Ce-based compounds having similar composition and structure. © 2009 The American Physical Society.

We report measurements of the de Haas-van Alphen effect on a series of compounds, LaMIn5 (M=Co,Rh,Ir). The results show that each of the Co and Ir Fermi surfaces (FSs) exhibits some portions that are two dimensional and some portions that are three dimensional. The most two-dimensional character is exhibited in LaCoIn5, less two-dimensional behavior is seen in LaIrIn5, and no part of Fermi surface of LaRhIn5 is found to have a two-dimensional character. Thus the two dimensionality of portions of the FSs is largely determined by the d character of the energy bands while all of the effective masses remain ≤1.2. This fact has implications for the causes of the heavy fermion nature of superconductivity and magnetism in the Ce-based compounds having similar composition and structure. © 2009 The American Physical Society.

The interaction of gallium and palladium with 2 nm CeO2(111) layers grown on Cu(111) was studied by core level photoelectron spectroscopy and resonant valence band spectroscopy. Palladium alone interacted weakly with ceria layers. Gallium deposited on cerium dioxide formed a mixed Ga2O3-Ce2O3 oxide of 1:1 stoichiometry (cerium gallate CeGaO3), with both metals in the M3+ oxidation state. Increasing Ga coverages led to the formation of lower oxidation states, i.e., Ga1+ in Ga2O oxide and metallic Ga0. Palladium deposited onto this complex system interacted with gallium leading to a breakage of Ga-ceria bonds, a decrease of the oxidation state of gallium, and formation of a Ga-Pd intermetallic alloy in which all components (CeO2, CeGaO3, Ga2O, Ga-Pd, and Pd) are in equilibrium. [ABSTRACT FROM AUTHOR]

• A Modified Embedded Atom Method (MEAM) potential for classical molecular dynamics simulation of gamma cerium was generated. • A two-step optimization procedure was used. • The first step was an automated fit to energies and forces from Density Functional Theory calculations. • The second step was human guided optimization to experimentally determined material properties. • The simulations successfully reproduce a wide range of properties of gamma cerium. As interest in Cerium containing alloys and Al-Ce alloys in particular grows, the need to generate predictions of mechanical, thermodynamic and transport properties across a compositional space becomes more pronounced. The absence of a reliable interaction potential to be used in classical molecular dynamics (MD) simulation of γ-Ce is a fundamental bottleneck to subsequent alloy simulation. In this work, a Modified Embedded Atom Method (MEAM) potential to be used in MD simulation for γ-Ce has been generated. The parameterization process involved two steps. First, the iterative Latin hypercube sampling (LHS) method was used to generate MEAM parameter sets based on an automated optimization of energies and forces relative to a training set of small configurations evaluated through Density Functional Theory (DFT). Second, a human-guided optimization in that local parameter space was performed to refine the parameters to satisfy an array of mechanical, thermodynamic and transport properties available from the experimental literature. When used in an MD simulation, the resulting potential provides excellent estimates of all tested material properties across a broad temperature range. This γ-Ce potential, when combined with existing MEAM potential for Al, will form the necessary foundation for the subsequent development of a mixture potential, enabling the simulation of Al-Ce and Al-Ce-X alloys. [ABSTRACT FROM AUTHOR]

In this study, we report the effect of cerium (Ce) addition on the tension-compression yield and cyclic asymmetry in commercially pure magnesium (Cp-Mg) and Mg–Al alloy at room temperature (RT). The investigated materials Cp-Mg, Mg-0.5Ce, and Mg–3Al-0.5Ce were extruded at 400 °C, followed by annealing at the same temperature for 1 h. Incorporating 0.5 wt% Ce in pure Mg results in the weakening of its basal texture, uniform distribution of Mg 12 Ce precipitates, and grain size refinement. Consequently, the tensile yield strength and ductility of pure Mg increased, and tension-compression yield asymmetry was eliminated. However, the presence of 3 wt% Al in Mg suppresses the beneficial effects of Ce addition. The formation of non-uniformly distributed complex precipitates, such as Mg–Al–Ce and Al 11 Ce 3, limits the weakening of the basal texture, reduction in grain size, improvement in ductility, and elimination of tension-compression yield asymmetry observed in Mg-0.5Ce. Nevertheless, Al contributes to the solid solution strengthening in Mg and possibly lowers the critical stress required for twinning in Mg, resulting in the highest tensile strength of Mg–3Al-0.5Ce. Finally, the addition of 0.5 wt% Ce enhances the cyclic strength, stabilizes cyclic stress response, reduces inelastic strain, and minimizes cyclic asymmetry in both pure Mg and Mg–Al alloy while maintaining a comparable fatigue life. Overall, Ce addition positively impacts the microstructure and mechanical behavior of pure Mg and its investigated alloy. The reasons for these improvements are discussed in detail. [ABSTRACT FROM AUTHOR]

A self-consistent model of thorium dioxide and its dilute alloys with cerium is developed. Thermal and elastic properties of ThO2 and several variations of Ce 0. 0 5 Th 0. 9 5 O2 synthesized by various techniques (powder processing and pelletization (POP) and coated agglomerate pelletization process (CAP) and using two different atmospheres, i.e., air or Ar + H2 mixture) are simulated. The influence of porosity on degree of phonon anharmonicity and on the lattice properties (in particular, thermal conductivity) of the considered systems is analyzed. [ABSTRACT FROM AUTHOR]

The inhibition effect of 3‐pyridyl‐4‐amino‐1,2,4‐triazole‐5‐thiol (C7H7N5S) and its cerium nitrate (Ce(NO3)3) compound on the corrosion of LY12CZ aluminum in 3.5% NaCl was investigated by means of potentiodynamic polarization (PP), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), and energy dispersive spectrometer (EDS). Results showed that the inhibition efficiency reached 77.61% at 0.8 g L−1 concentration and was found to increase with increasing concentration of C7H7N5S. C7H7N5S is a mixed type inhibitor. The desorption onset potential was obtained from differential polarization curve. EDS data indicated that C7H7N5S can adsorb on the S phase and inhibit the cathode action of the S phase. Both kinetic and thermodynamic parameters were calculated and discussed. The adsorption of C7H7N5S on aluminum surface was found to obey the Langmuir adsorption isotherm, and being both physisorption and chemisorption. C7H7N5S and Ce(NO3)3 have an additive inhibition effect. The additive action improved the surface coverage of the aluminum and the stability of the adsorbed layer. [ABSTRACT FROM AUTHOR]

To balance the utilization of rare earth (RE) resource and develop Ce-based permanent magnets with high performance/cost ratio, the role of La substitution in the melt-spun (Ce1−xLax)yFe14B (x = 0-0.4, and 0.5; y = 2-4) alloys has been investigated. It has been confirmed that the hard magnetic properties of Ce-based magnets can be effectively enhanced by partial substitution of La. The maximum (BH)max of (Ce,La)-Fe-B alloys can be obtained at a Ce:La atomic ratio of 7:3. The lattice parameters and Curie temperature of the hard magnetic (Ce/La)2Fe14B phase increase linearly with increasing La content. Three different alloy systems with y = 2, 2.5 and 3 show similar behavior of magnetic properties dependences on La. In the RE-rich compositions, La substitution for Ce can effectively inhibit the precipitation of the CeFe2 phase. A solid solution, Ce(La) phase with a space group of Fm-3m, appears in the (Ce0.7La0.3)yFe14B alloys with y ≥ 3.5. A good combination of magnetic properties with Hcj = 345 kA/m, J5T = 1.03 T, Jr = 0.60 T, and (BH)max= 6.3 MGOe is obtained in (Ce0.7La0.3)2.5Fe14B alloy. In addition, 30 at.% La substitution for Ce can significantly refine the grains, resulting in the enhancement of exchange coupling interaction. The present finding is beneficial for designing new and low-cost magnetic materials. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Three separate adoption scenarios by the U.S. automotive market are considered for aluminum-cerium alloys. • Segregation is likely for most adoption scenarios and impurity thresholds. • Cerium demand is lowest at 1,000 mt/yr if the target market is diesel light trucks. • Given current primary Ce production capacity, 30% of the light duty vehicle market can adopt Al-Ce blocks and heads in 2045. Abstract Increasing demand of abundant co-product rare earths such as cerium and lanthanum has become a focus for improving mine economics. The recent development of an aluminum-cerium (Al-Ce) alloy targeted toward broad market adoption in the automotive industry is one recent example. This alloy has shown exceptional mechanical properties and cost-saving potential. However, since market adoption is unknown, impacts of this alloy on Ce demand remains uncertain. We estimate Al-Ce impacts by simulating adoption in different automotive sectors using a dynamic material flow analysis model. We then project future Ce content in the recycled Al stream given current recycling practices. We also compute the required segregation given different Ce impurity tolerances of existing automotive Al alloys. Finally, once secondary supply is derived from segregation, we calculate primary Ce demand. Results showed that segregation of Al-Ce components from non-AlCe automotive Al components is needed for most adoption scenarios and impurity thresholds. Ce metal demand was found to be lowest at 1000 mt/yr if the target market is light duty trucks. If Al-Ce could penetrate the High Efficiency Spark Ignition market (i.e., turbocharger market), Ce demand could reach 23,200 mt Ce/year in 2045, without accounting for Chinese and Australian Ce primary production capacity. When accounting for primary Ce production capacity, demand could reach up to 16,200 mt/yr. [ABSTRACT FROM AUTHOR]

Abstract In order to understand the effects of rare element substitution on activation performance of Laves phase-related BCC solid solution alloys, cerium (Ce) is used to partial substitute for Mn in Ti 33 V 37 Mn 30 alloy. Results show that Ce substitution leads to the formation of Ce/CeO 2 while decreases C14 Laves phase. Ce substituting alloys can absorb hydrogen without being activated at a high temperature, which means the activation performance of Ti 33 V 37 Mn 30 alloys is improved greatly by the Ce/CeO 2 rather than C14 Laves phase. The maximum hydrogen absorption capacity also increases when Ce content increases. The hydrogen absorption capacity and effective hydrogen storage capacity reach the maximum when the composition is Ti 33 V 37 Mn 29.4 Ce 0.6 , with the values of 3.35 wt% at 293 K and 2.25 wt% at 423 K. The dehydriding enthalpy (ΔH) of 0.6 at.%-Ce-substituting alloy is higher than that of Ce-free alloy, which indicates that Ce substitution can increase the stability of hydrides. Highlights • Ce substitution decreases the formation of C14 Laves phase. • The Ce substitution improves the activation performance rather than C14 Laves phase due to the formation of CeH 2.51. • Ce substitution improves the hydrogen storage properties of Ti 33 V 37 Mn 30 alloy. • Ce substitution increases thermal stability of the hydride. [ABSTRACT FROM AUTHOR]

Abstract A Ca-containing Mg-4Zn-1MM(mischmetal)-0.1Ca (wt.%, ZEX4101) alloy sheet shows Index Erichsen value of 6.7 mm, which is better than commercial Mg alloy sheets. The good formability is attributed to its weakened basal texture, in which the intensity of the (0001) poles of the recrystallized grains spreads towards the transverse direction. By monitoring the microstructural evolution during the hot rolling and the solution treatment, we found that Ca addition hinders the formation of strong basal texture during the rolling. During the subsequent solution treatment, static recrystallization mainly proceeds by the growth of dynamically recrystallized grains, and then the weak texture feature of the dynamically recrystallized grains is maintained in the ZEX4101 alloy sheet. It is hypothesized that co-segregation of Zn and Ca atoms to the grain boundaries prevents the rotation of the (0001) poles of the dynamically recrystallized grains toward the sheet normal direction, resulting in the development of weak basal texture in the ZEX4101 alloy sheet. Highlights • Trace Ca addition weakens basal texture and increases room-temperature stretch formability in Mg-4Zn-1MM alloy sheet. • Ca-containing Mg-4Zn-1MM-0.1Ca alloy sheet causes co-segregation of Zn and Ca atoms to grain boundaries. • Co-segregation of Zn and Ca prevents formation of strong basal texture during hot-rolling. [ABSTRACT FROM AUTHOR]

Abstract Phase transformations in the Ce-Fe-Ni ternary system have been studied using DTA, X-ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). Liquidus and solidus projections and a Scheil diagram for solidification were constructed. A continuous solid solution between the Laves phase compounds, CeFe 2 and CeNi 2 , with cubic MgCu 2 -type structures forms in this system at the solidus temperatures. A new binary compound Ce 5 Ni 19 was found in the Ce-Ni system. The binary system-based phases, CeNi 5 , Ce 5 Ni 19 , Ce 2 Ni 7 and CeNi 3 , have the widest homogeneity regions and dissolve at the solidus temperature up to 29.4, 23.4, 25.6 and 35.4 at.% Fe, respectively. The homogeneity regions of the remaining phases are smaller. No ternary compounds have been identified in this system. Seven three-phase fields in the solidus surface result from three transition type, two peritectic and two eutectic invariant four-phase equilibria. Highlights • A new binary compound Ce 5 Ni 19 has been identified for the first time. • Liquidus and solidus projections and a Scheil diagram were constructed for the Ce-Fe-Ni system. • Appreciable solubilities of Fe were observed in the binary compounds. • No ternary compounds have been identified in this system. [ABSTRACT FROM AUTHOR]

Abstract Low anisotropy field and low Curie temperature of Ce 2 Fe 14 B phase seriously restrict the application of Ce-Fe-B alloys. Most of the previous work suggest that REFe 2 phase inevitably forms in the compositions with high Ce content. In this work, Si substitution for Fe is found to not only suppress the formation of CeFe 2 phase, but also significantly improve the coercivity H c and thermal stability of Ce 17 Fe 78-x Si x B 6 (x = 0–3.0) alloys. All Si-doped alloys exhibit higher H c and better thermal stability than Ce 17 Fe 78 B 6 alloy. With increasing Si doping, a relatively high H c = 525 kA/m is obtained in the Ce 17 Fe 77.75 Si 0.25 B 6 alloy. An abnormal increase of H c as well as almost unchanged J r and (BH) max is observed in Ce 17 Fe 78-x Si x B 6 (x > 1.5) alloys. The refined XRD results indicate that the volume fraction of CeFe 2 phase can be dramatically reduced via a moderate content of Si doping. Hard magnetic grains are isolated by forming a structure with thin and continuous intermediate layer, consequently preventing the domain wall propagation. The Curie temperature of the main phase monotonically increases from 424 K for x = 0–445 K for x = 3.0, resulting in improved thermal stability. The highest H c of 530 kA/m, the lowest temperature coefficients (| β | = 0.551%/°C and | α | = 0.368%/°C), and an acceptable J r = 0.44 T are obtained in Ce 17 Fe 78-x Si x B 6 (x = 3.0) alloy. The nucleation and pinning are both responsible for the coercivity mechanism of Ce 17 Fe 75 Si 3 B 6 alloy, which should be the reason for its high coercivity. Highlights • The formation of undesired CeFe 2 phase is suppressed by Si doping. • Si doping increases Curie temperature and improves thermal stability. • A structure with thin and continuous grain boundary phase is formed by Si doping. • Increased H c and almost unchanged J r and (BH) max can be obtained in Si doped alloys. • A domain wall pinning effect is observed in Ce 17 Fe 75 Si 3 B 6 alloy. [ABSTRACT FROM AUTHOR]

Highlights • Three hard magnetic phases coexist in Ce-Fe-B magnets prepared by dual alloy method. • Rare earth elements diffuse during sintering process result in the formation of Pr-Nd-Ce-Fe-B hard magnetic phase. • The intergranular exchange coupling strength is enhanced with increasing Pr-Nd-Fe-B content. Abstract Ce-Fe-B spark plasma sintered (SPSed) magnets prepared with different ratio of alloys of Ce-Fe-B and Pr-Nd-Fe-B by dual alloy method are investigated in this paper. As expected, the remanent magnetization J r , coercivity H ci and maximum energy product (BH) max of SPSed magnets increase obviously with increasing weight percentage of Pr-Nd-Fe-B alloy. The magnetic properties of J r = 0.71 T, H ci = 915 kA/m, (BH) max = 72 kJ/m3 are obtained for the SPSed magnets with 80 wt% Pr-Nd-Fe-B alloy. There are three Curie temperatures in this type magnet, which implies the coexistence of three hard magnetic phases. The second Curie temperature depends on the Pr-Nd-Fe-B content. With increasing Pr-Nd-Fe-B alloy content, the volume fraction and width of coarse grain zone decrease. It is shown by the microstructure analysis that the rare earth elements diffuse during sintering process resulting in the formation of Pr-Nd-Ce-Fe-B hard magnetic phase. The intergranular exchange coupling strength is enhanced with increasing Pr-Nd-Fe-B content. The present research may be a potential reference for further research and development of this type Ce-containing nanocrystalline permanent magnetic materials. [ABSTRACT FROM AUTHOR]

Flaky microwave absorbing materials based on Ce2Co17 with different addition of Ni content were fabricated successfully using the method of vacuum arc melting and high energy ball milling. The phase structure, grain morphology, electromagnetic parameters and reflection loss (RL) were probed by the corresponding equipment and computational simulation software. The RL values of Ce2Co17−xNix alloys that exceeded − 10 dB were observed in the frequency range of 6.16-10.24 GHz with a thickness of only 1.8 mm. Besides, via adjusting the thickness to only 1.6 mm, the minimum RL of Ce2Co16.6Ni0.4 powder was as high as − 44.29 dB at 9.6 GHz with a broad bandwidth of 3.04 GHz. Furthermore, the different weight ratio for Ce2Co16.6Ni0.4/carbonyl iron powder composite was also studied. The microwave absorption peak of composite shifts to a higher frequency region with the increasing weight ratio of carbonyl iron powder. More importantly, the effective bandwidth of the composite with the Ce2Co16.6Ni0.4/carbonyl iron powder weight ratio of 50:50 can be obtained at about 4.64 GHz, manifesting that composite can be provided with excellent microwave absorption bandwidth by adjusting the weight ratio of carbonyl iron powder. [ABSTRACT FROM AUTHOR]

Abstract Ce-Fe-B-based rare earth permanent magnets are prepared by spark plasma sintering (SPS) technique, and low melting NdCu alloy is added to improve its magnetic properties and thermal stabilities. The X-ray diffraction (XRD) result indicates that the lattice constants of the unit cell of 2:14:1 phase increase with NdCu addition. The remanent magnetization, coercivity and maximum energy product are enhanced remarkably from 0.37 T, 227 kA/m, 16 kJ/m3 for the sintered magnets without NdCu addition to 0.47 T, 476 kA/m, 30 kJ/m3 for those with 20 wt% NdCu addition. The temperature coefficients of remanence (α) and coercivity (β) of the spark plasma sintered magnets (denoted as SPSed magnets thereafter) are improved from −0.46%/K, −0.60%/K to −0.34%/K, −0.55%/K in the range of 300–400 K. There are two Curie temperatures in the Ce-based magnets with NdCu addition, which implies the coexistence of two hard magnetic phases. The second Curie temperature depends on the NdCu content. It is shown by the microstructure analysis that a typical core-shell structure is formed with Ce-rich core and Ce-lean shell by NdCu addition. Furthermore, it is displayed that Nd atoms prefer to diffuse into the Ce-lean flakes. The Nd-Ce exchange mechanism and immigration behavior of elements are finally investigated. The intergranular exchange coupling strength is enhanced in NdCu-added magnet. It is found out that the core-shell structure plays an important role in the special microstructure evolution and the enhancement of the magnetic properties for the typical Ce-Fe-B-based SPSed magnets by NdCu addition. Highlights • There are two Curie temperatures in the Ce-based magnets with NdCu addition. • A typical core-shell structure is formed by NdCu addition. • The intergranular exchange coupling strength is enhanced in NdCu-added magnet. • The Nd-Ce exchange mechanism is investigated. [ABSTRACT FROM AUTHOR]

Abstract The RE-rich (Ce 1−x Nd x) 16 Fe 78 B 6 (x = 0–1) nanocrystalline alloys were prepared by melt-spinning method. The transmission electron microscopy equipped with EDS was employed to investigate the microstructure and rare-earth element segregation. The average Nd/RE ratios in 2:14:1 grains are 22, 52, 67, 74, 78, and 81% for the x = 0.1, 0.4, 0.5, 0.6, 0.7, and 0.8 alloys, respectively, which are larger than the nominal ratios, indicating a Nd segregation in 2:14:1 phase. The Nd/RE ratio changing with x shows a two-stage of increment: the average increment in x = 0.1–0.5 alloys is much higher than that of x = 0.5–0.8 alloys. The corresponding change is also observed in the plotted intrinsic parameters of cell volume V , hyperfine field B hf , and spin reorientation temperature T SR of the 2:14:1 phase changing with x curves. The high Ce-contained RE-rich Nd-Ce-Fe-B with strong element segregation shows high coercivities and high performance/price ratio. The present results thus contribute to understanding the fundamental mechanism of Ce-contained Nd-Ce-Fe-B permanent magnets and taking advantage of the element segregation. Highlights • Strong RE segregation is observed in the nanocrystalline (Ce 1−x Nd x) 16 Fe 78 B 6 (x = 0–1) alloys. • Both the magnetic properties and Nd/RE ratios in 2:14:1 phase show a two-stage change with the increasing Nd content. • The Ce segregation in 1:2 phase promotes the element segregation and further increases the Nd/RE ratios in 2:14:1 phase. [ABSTRACT FROM AUTHOR]

Abstract The Ce-Co-Fe phase diagram was investigated for the whole concentration range at 900 °C, using X-Ray diffraction (XRD), scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). An isothermal section at this temperature was constructed. Two continuous solid solutions Ce 2 (Co,Fe) 17 (Th 2 Zn 17 -type structure, hR57-R-3m ) and Ce(Co,Fe) 2 (MgCu 2 -type structure, cF24-Fd-3m ), found by us both at the solidus temperatures and at 900 °C, contain 11 and 33.3 at.% Ce, respectively, due to mutual substitution of Fe and Co atoms. The liquid phase is present in the system at 900 °C. The isothermal section at this temperature is characterized by the five three-phase regions (αFe) + (αCo) + Ce 2 (Co,Fe) 17 , Ce 5 Co 19 + CeCo 5 + Ce 2 Co 7 , CeCo 5 + Ce 2 (Co,Fe) 17 + Ce 2 Co 7 , Ce 2 Co 7 + Ce 2 (Co,Fe) 17 + CeCo 3 and CeCo 3 + Ce 2 (Co,Fe) 17 + Ce(Co,Fe) 2 and associated two-phase fields. CeCo 3 and Ce 2 Co 7 show the widest homogeneity regions and dissolve up to 49 at.% and 21 at.% Fe respectively. The solubility of Fe in the other crystalline phases is smaller. Highlights • Phase equilibria in the Ce-Co-Fe system at 900°С were studied. • An isothermal section at this temperature was constructed. • Two continuous solid solutions Ce 2 (Co,Fe) 17 and Ce(Co,Fe) 2 form in this system. • CeCo 3 and Ce 2 Co 7 intermetallics have the widest homogeneity regions. [ABSTRACT FROM AUTHOR]