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We realize a facile chromaticity tuning for the Y 3 Al 5 O 12 :Ce 3+ phosphor-in-glass (PiG) based w-LED, with the aid of a CaAlSiN 3 :Eu 2+ red phosphor layer in a remote-type stacking configuration. It was experimentally demonstrated that both the stacking order and the relative amount of red phosphor influence the electroluminescent performance of the constructed w-LED significantly, and the optimized warm w-LED exhibits admirable performance with a luminous efficacy of 93.9 lm/W, a correlated color temperature of 3346 K, a color rendering index of 77.3, and a color shift deviating from Planckian locus in D uv of 0.0034. Significantly, the red phosphor layer stacked PiG based warm w-LED presents an excellent heat resistance, endowing the device with long life-time, which may serve as a promising robust high-power indoor lighting source. [ABSTRACT FROM AUTHOR]

A variation in the electron population of the conduction band due to variation in the aggregate state of the Al-8 at % Ce alloy is demonstrated using optical experimental data: zero, partial, and maximum populations correspond to the melt, amorphous state, and polycrystal, respectively. [ABSTRACT FROM AUTHOR]

Glass forming ability, thermal stability and indentation characteristics of Ce 60 Cu 25 Al 15 − x Ga x (0 ≤ x ≤ 4) metallic glasses have been investigated. Amorphous phase has been confirmed in all these samples with the help of X-ray diffraction (XRD), differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) studies. The compositional dependence of the glass forming ability (GFA) and its correlation with related parameters as well as thermal stability have also been discussed. The load dependent hardness behavior of metallic glasses is reported in detail. It has been observed that substitution of 1 at.% Ga improved micro-hardness property of Ce–Cu–Al–Ga alloy. The value of yield strength of the materials is estimated with the help of hardness data and Meyer exponent. It has been found that this exponent decreases with respect to Ga substitution. [ABSTRACT FROM AUTHOR]

The effect of Ce substitution for (Nd,Pr) on structure, microstructure, and magnetic properties of [(Nd0.75Pr0.25)1–xCex]11.65Fe82.75B5.6 ( $x=0$ –0.5) melt-spun powders has been studied. It has been found that all Ce-substituted powder samples retain the R2Fe14B ( \textrm {R}=\textrm {Nd} , Pr, Ce) single-phase structure with a similar grain size in the range of 20–22 nm. While Ce substitution leads to lower magnetic properties, lower Curie temperature, and higher flux aging loss in bonded magnets, (Nd,Pr,Ce)–Fe–B melt-spun powders with up to 50% Ce substitution exhibit acceptable overall room-temperature magnetic properties and improved magnetization behavior, and offer a potential low-cost alternative product for low-to-moderate-temperature applications. [ABSTRACT FROM AUTHOR]

Extensive efforts have been made to develop metallic-glasses with large casting diameter. Such efforts were hindered by the poor understanding of glass formation mechanisms and the origin of the glass-forming ability (GFA) in metallic glass-forming systems. In this work, we have investigated relaxation dynamics of a model bulk glass-forming alloy system that shows the enhanced at first and then diminished GFA on increasing the percentage of micro-alloying. The micro-alloying did not have any significant impact on the thermodynamic properties. The GFA increasing on micro-alloying in this system cannot be explained by the present theoretical knowledge. Our results indicate that atomic caging is the primary factor that influences the GFA. The composition dependence of the atomic caging time or residence time is found to be well correlated with GFA of the system. [ABSTRACT FROM AUTHOR]

A composite H-β zeolite membrane encapsulated 8wt%Ni/8wt%Mg/Ce 0.6 Zr 0.4 O 2 steam reforming catalyst was prepared by a physical coating method using silica sol as a binder between the H-β zeolite shell and steam reforming catalyst core. Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) analyses indicated that H-β zeolite was coated successfully on the core reforming catalyst and the shell thickness was at least 100 nm. The pore size of H-β zeolite shell was between 0.43 and 0.57 nm, as measured by the HK method. Steam reforming of CH 4 and C 7 H 8 (as a tar model) were conducted with the composite H-β zeolite coated reforming catalyst, the two components individually, and physical mixtures of the two components as a function of temperature (780–840 °C). CH 4 conversion was enhanced by a factor of 2–3 (depending on temperature) for the composite catalyst as compared to the core reforming catalyst individually even though the zeolite did not have any activity alone. Possible reasons for the enhanced CH 4 conversion include confined reaction effects (increase residence time within pores) of the catalyst containing the zeolite coating and/or Al 3+ promotion of the active sites. Alternatively, due to molecular-size selectivity, the composite H-β zeolite coated reforming catalyst demonstrated a decrease in C 7 H 8 conversion when compared to the uncoated reforming catalyst. The results validate the use of size selective catalysts to control molecular traffic and enhance the reforming reactant selectivity. [ABSTRACT FROM AUTHOR]

We report the γ – α isostructural transition and α - bct phase transition in Ce–La alloy under pressure within the generalized gradient approximation plus on-site Coulomb interaction (GGA + U ) method. The equation of state and volume collapse transition between γ and α phases were predicted. By using quasi-harmonic Debye model, we obtained the γ – α transition boundary. The predicted γ – α transition pressures increase with the increasing temperature and the increasing La concentration in the Ce–La alloy. [ABSTRACT FROM AUTHOR]

A Cu–0.3 wt.%Mg–0.05 wt.%Ce alloy was designed and prepared by melting and casting. After hot rolled, the ingot was cut into rod-shape samples for equal channel angular pressing (ECAP) with different passes at room temperature. The microstructure evolutions were investigated using transmission electron microscope (TEM) observation and electron backscatter diffraction (EBSD) analysis. The severe plastic deformation (SPD) caused by ECAP made the grains elongated significantly. With the increase of ECAP passes, the fraction of high-angle boundaries (HABs) ( θ ⩾ 15°) increased and the microstructure was refined. Tension testing results indicated that the tensile strength was remarkably improved from 273.4 MPa before ECAP to 587.5 MPa after 8 passes of ECAP, maintaining an appropriate elongation of 11.4% and good electrical conductivity of 73.1%IACS. After annealing treatment at 300 °C for 2 h, the ECAP samples still maintained excellent comprehensive properties: tensile strength was 558.2 MPa, electrical conductivity was 74.7%IACS, and elongation was 13.2%, which showed bright prospect in high-speed railway as a contact wire material. [ABSTRACT FROM AUTHOR]

The article discusses the supplemental literature review of binary phase diagrams of alloys. Topics include the thermodynamical analysis of new phase diagrams, reaction tables, and crystal structure data. Presented phase diagrams of alloys includes gold-cerium (Au-Ce), boron-praseodymium (B-Pr), and bismuth-gadolinium (Bi-Gd).

In order to improve magnetostriction of the polycrystalline Fe-Ga alloy, the rare earth element Ce was firstly doped into Fe 83 Ga 17 and the melt-spinning method was subsequently applied. The as-cast Fe 83 Ga 17 and Ce-doped Fe 83 Ga 17 alloys were prepared by arc melting. Then the as-cast Ce-doped Fe 83 Ga 17 alloy was melt-spun by the melt-spinning technique. The microstructures and magnetostrictions of all these three alloys were investigated by X-ray diffractometer (XRD), scanning electron microscopy and energy dispersive spectroscopy (SEM/EDS), differential scanning calorimeter (DSC) and magnetostriction measurements. The results indicated that the CeGa 2 phase and asymmetrical DO 3 phase are formed caused by Ce-doping and melt-spinning, respectively. The magnetostrictions of three alloys are ranked in sequence the melt-spun Fe 83 Ga 17 Ce 0.8 alloy > as-cast Fe 83 Ga 17 Ce 0.8 alloy > as-cast Fe 83 Ga 17 alloy. The enhanced magnetostriction is attributed to the fact that the formation of new phases and the preferred orientation along (100) direction. [ABSTRACT FROM AUTHOR]

A series of novel catalysts (Ce x Sn y ) for the selective catalytic reduction of NO by NH 3 were prepared by the inverse co-precipitation method. The aim of this novel design was to improve the NO removal efficiency of CeTi by the introduction of SnO 2 . It was found that the Ce–Sn–Ti catalyst was much more active than Ce–Ti and the best Ce:Sn molar ratio was 2:1. Ce2Sn1 possessed a satisfied NO removal efficiency at low temperature (160–280 °C), while over 90% NO removal efficiency maintained in the temperature range of 280–400 °C at the gas hourly space velocity (GHSV) of 50,000 h −1 . Besides, Ce2Sn1 kept a stable NO removal efficiency within a wide range of GHSV and a long period of reacting time. Meanwhile, Ce2Sn1 exhibited remarkable resistance to both respectively and simultaneously H 2 O and SO 2 poisoning due to the introduction of SnO 2 . The promotional effect of SnO 2 was studied by N 2 adsorption–desorption, X-ray diffraction (XRD), Raman spectra, X-ray photoelectron spectroscopy (XPS) and H 2 temperature programmed reduction (H 2 -TPR) for detail information. The characterization results revealed that the excellent catalytic performance of Ce2Sn1 was associated with the higher specific surface area, larger pore volume and poorer crystallization. Besides, the introduction of SnO 2 could result in not only greater conversion of Ce 4+ to Ce 3+ but also the increase amount of chemisorbed oxygen, which are beneficial to improve the SCR activity. More importantly, a novel peak appearing at lower temperatures through the new redox equilibrium of 2Ce 4+ + Sn 2+ ↔ 2Ce 3+ + Sn 4+ and higher total H 2 consumption can be obtained by the addition of SnO 2 . Finally, the possible reaction mechanism of the selective catalytic reduction over Ce2Sn1 was also proposed. [ABSTRACT FROM AUTHOR]

The mixing enthalpies of liquid binary Ce-In alloys (0 < x < 1) at 1500 K are determined by isoperibol calorimetry. The thermodynamic properties of the liquid Ce-In alloys are calculated for the entire composition range using the model of ideal associated solutions. The thermodynamic activities of melt components show negative deviations from the ideal behavior. The mixing enthalpies are characterized by significant exothermic effects. The minimum mixing enthalpies of the melts are -43.8 ± 0.2 kJ/mol at x = 0.57. [ABSTRACT FROM AUTHOR]

Isothermal sections of the Al-Ce-Zn ternary system in the Ce-poor regions (≤33.3 at.%Ce) at 450 and 600 °C were determined experimentally using the equilibrated alloy approach. Twelve three-phase regions were identified at both 600 and 450 °C. The ternary compound τ (AlCeZn) was well confirmed. Its Ce content is around 20 at.% and at 600 °C the Zn content spans 27.5-71.6 at.%, while correspondingly, the Al content spans 53.3-8.1 at.%. At 450 °C the span is similar, but somewhat less. The a lattice parameter for τ increases with Al concentration at lower Al contents in the span, whereas the c lattice parameter increases with Al concentration at higher Al contents in the span. The maximum solubility of Zn in AlCe and AlCe at 600 °C is 17.9 and 20.7 at.%, respectively. And that of Al in CeZn, CeZn, CeZn, CeZn, CeZn, CeZn, CeZn, and CeZn at 600 °C is 12.5, 17.6, 4.9, 2.5, 0.6, 2.2, 6.3, and 32.4 at.%, respectively. All these solubilities decrease a little when the temperature turns to 450 °C. [ABSTRACT FROM AUTHOR]

Different concentrations of europium (Eu), cerium (Ce) doped and co-doped ZnO:Eu (1%), Ce (1%) nanorods were successfully synthesized by chemical method using Polyvinylpyrrolidone as a surfactant. Crystalline phase, morphology, functional groups, optical absorption, emission and thermal properties of prepared samples were investigated by X-ray diffraction (XRD), X-ray photoelectron spectrometer (XPS), Scanning electron microscopy (SEM), High-resolution transmission electron microscopy (HR-TEM), Fourier transform infra-red (FT-IR), UV–visible, Photoluminescence (PL) spectrophotometer and thermogravimetry (TG) and differential thermal analysis (DTA) analysis. The XRD study showed high crystalline nature of the products with nanoscale regime. Optical study showed shifting the absorption and emission spectra toward higher wavelength side when increasing the doping concentrations. Mainly, this is first time observed a red emission peak at 660 nm for Ce (3%) doped ZnO. Additionally, co-doped ZnO:Eu (1%), Ce (1%) nanorods were synthesized and studied their optical properties. This work demonstrates that simply modified their optical absorption and emission of ZnO by introducing rare earth ions can be used as an effective electrode material in solar cell applications, optoelectronic devices and photocatalysis analysis. [ABSTRACT FROM AUTHOR]

Steam reforming of propane over a novel Ir/Ce 0.75 Zr 0.25 O 2 catalyst was investigated. Various techniques such as X-ray diffraction (XRD), temperature-programmed reduction (TPR), high resolution transmission electron microscopy (HRTEM), and oxygen storage capacity (OSC) etc were used to characterize the as-prepared catalysts in order to elucidate the catalyst structure-performance relationship. The doping of ZrO 2 into the CeO 2 lattice greatly improved the redox property of the CeO 2 by creating more surface oxygen vacancies. Stability test revealed that the Ir/Ce 0.75 Zr 0.25 O 2 sample exhibited rather stable catalytic behavior for 65 h time-on-stream without obvious deactivation, which was assigned to the efficient prevention of the sintering of the highly dispersed Ir particles through the strong interaction between Ir and CeO 2 support and to the significant resistance to coke deposition due to the excellent OSC of Ce 0.75 Zr 0.25 O 2 support. [ABSTRACT FROM AUTHOR]

Ce–Zr–Cu mixed oxide systems, with different contents of ZrO 2 and CuO, were prepared by slow co-precipitation method, leading to the formation of materials with a flower-like morphology. It was evaluated both the role of CuO loading (3–7 wt%), by maintaining constant the amount of ZrO 2 (7 wt%), and the role of ZrO 2 (2–10 wt%) with a fixed amount of CuO (7 wt%). The prepared catalysts were characterized by means of ICP-OES, SEM, N 2 physisorption, quantitative XRD, H 2 -TPR, and XPS. Their catalytic performances in the preferential oxidation of CO in excess of H 2 (CO-PROX) were evaluated, in the 40–190 °C temperature range. Characterization and catalytic results showed that an optimum Zr/Ce molar ratio and CuO loading are required to attain the best catalytic performance over the studied nanostructured Ce/Zr/Cu oxide system. Characterization results revealed that, regardless of the sample composition, all of them presented similar flower-like morphology and textural properties. Instead, the catalyst composition determined the crystalline phases formed, their reducibility and surface distribution. The catalyst containing an intermediate ZrO 2 loading (7 wt%) and the highest studied CuO amount (7 wt%), FCZCu77, showed the higher fraction of undetectable CuO from XRD, that is the highest proportion of highly dispersed Cu species also observed from H 2 -TPR. These characteristics justify how FCZCu77 catalyst exhibited a quite higher catalytic activity than the others samples. [ABSTRACT FROM AUTHOR]

In the present study, the influence of minor cerium (Ce) additions (up to 1 wt.%) to AM50 magnesium alloy on the plasma electrolytic oxidation (PEO) process and the corrosion performance of the PEO coatings were studied. Therefore, a silicate-based PEO coating was deposited on AM50 containing 0, 0.5 and 1 wt.% Ce under the same processing conditions. The resulting surface morphology, cross-sectional microstructure, phase and chemical compositions of the coatings were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction analyses (XRD). The corrosion behaviour of the coatings was evaluated by salt spray and electrochemical corrosion tests. The results show that the growth rate of the coating is reduced, but the thickness is becoming more uniform if cerium is added to AM50 alloy. However, the phase composition and coating morphology are hardly influenced, but the corrosion properties reveal large differences suggesting that the porous PEO coatings have to be considered as a system of coating and substrate. A more uniform corroding substrate such as the cerium alloyed AM50 provides much better protection in combination with a PEO coating than the pure AM50. Flaking-off of large coating areas was observed due to the volume increase caused by corrosion products forming in the interface. Such a severe localised corrosion in the interface causing delamination of the coating can be suppressed by cerium addition. [ABSTRACT FROM AUTHOR]

The effect of the element cerium on the microstructure and wear behavior of Fe-B cast alloy was investigated by scanning electron microscope, transmission electron microscope, X-ray diffraction analysis, Leica digital image analysis, hardness tester and abrasion tester. The microstructures of as-cast Fe-B alloy are composed of the phase ferrite, pearlite and eutectic boride. Moreover, the as-cast eutectic boride structures in Fe-B alloy containing cerium are finer than that in the alloy having no cerium. After heat treatment, the average boride area and wear weight loss of the alloy containing cerium are lower than these of the alloy having no cerium. Before the formation of primary austenite, cerium can combine with oxygen to form CeO. CeO can act as nuclei of primary austenite, promoting the refinement of austenite and borides during solidification, and improve the wear property of Fe-B alloy. [ABSTRACT FROM AUTHOR]

The isomeric yield ratios of 133m,g Ce and 137m,g Ce produced from the nat Ce(γ,xn) reactions were determined by using the activation and the off-line γ-ray spectrometric technique with the end-point bremsstrahlung energies of 55-, 60-, and 65-MeV at 100-MeV electron linac of the Pohang accelerator laboratory. The induced activities in the irradiated foils were measured by using an energy- and efficiency-calibrated HPGe detector coupled to a PC based multi-channel analyzer. The necessary corrections were made to improve the accuracy of the experimental results. The experimental results at bremsstrahlung energies of 55-, 60-, and 65-MeV were 0.324 ± 0.089, 0.331 ± 0.086, and 0.403 ± 0.089 for the 133m,g Ce, and 0.210 ± 0.062, 0.221 ± 0.061, and 0.262 ± 0.061 for the 137m,g Ce, respectively. The present results for nat Ce(γ,xn) 133m,g;137m,g Ce in this energy region were obtained for the first time which has no comparable literature data. The obtained isomeric yield ratios are compared with the calculated values based on the statistical model code TALYS 1.6. [ABSTRACT FROM AUTHOR]

The substitution for Nd by abundant element Ce is a practical way for the comprehensive utilization of rare earth resources in permanent magnets. In this letter, we investigate the magnetic properties and magnetization reversal of Nd 12 − x Ce x Fe 82 B 6 ribbons by varying x from 0 to 12. These ribbons mainly consist of R 2 Fe 14 B phase in isotropic nanostructure. Coercivity, Curie temperature and maximum energy product all decrease with the increase of Ce atomic percent. The decrease of coercivity is mainly attributed to the decrease of anisotropy due to the substitution for Nd by Ce. In Ce 12 Fe 82 B 6 and Nd 1 Ce 11 Fe 82 B 6 ribbons, the magnetization reversal behaviors are more non-uniform and the squareness of demagnetization curve is poor in second quadrant. However, as long as the Ce concentration does not exceed 10 at.%, the squareness of demagnetization curve remains good and the intergranular exchange coupling is strong. It is expected that these investigations could be beneficial to the composition designing in the manufacturing of R 2 Fe 14 B magnets. [ABSTRACT FROM AUTHOR]

The Ce–Co–Al ternary phase diagram has been reinvestigated at 973 K by means of powder X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy and differential thermal analyses. It contains 5 ternary phases (CeCo 2 Al 8 , Ce 2 Co 6 Al 19 , CeCoAl 4 , Ce 3 Co 3 Al 4 and CeCoAl) as well as 7 extensions in the ternary field of pseudo-binaries (CeAl 2 − x Co x with 0 ⩽ x ⩽ 0.18; CeCo 2 − x Al x with 0 ⩽ x ⩽ 0.21; CeCo 3 − y Al y with 0 ⩽ y ⩽ 0.20; Ce 2 Co 7 − x Al x with 0 ⩽ x ⩽ 0.73; Ce 5 Co 19 − y Al y with 0 ⩽ y ⩽ 0.20; CeCo 5 − x Al x with 0 ⩽ x ⩽ 0.71 and Ce 2 Co 17 − y Al y with 0 ⩽ y ⩽ 2.2). Two liquid areas are present at the Al and Ce-rich corners of this isothermal section. [ABSTRACT FROM AUTHOR]

Ce–Co and La–Co mixed oxides were synthesized by two different methods: exotemplating and evaporation. The obtained catalysts were evaluated for volatile organic compounds (VOCs) abatement, using toluene as model molecule. The materials were characterized by N 2 adsorption at −196 °C, X-ray diffraction (XRD), scanning electron microscopy (SEM), H 2 temperature-programmed reduction (H 2 -TPR) and NH 3 temperature-programmed desorption (NH 3 -TPD) in order to reveal the structure–activity relationship. The results obtained showed the superiority of mixed oxides compared to single oxides in toluene oxidation. Ce–Co mixed oxides were more active than La–Co samples. For Ce–Co materials, the exotemplating method produced catalysts which were more active than those prepared by the evaporation procedure. The former showed the best catalytic performances, with full conversion of toluene into CO 2 at about 250 °C. Temperatures higher than 320 °C were required with single oxides. Characterization studies revealed strong interactions between Ce (or La) and Co, leading to a fine dispersion of oxide phases in binary systems. As a result, both the surface area and reducibility of the catalysts increase, which can be accounted for the higher performance of the mixed oxides. Furthermore, NH 3 -TPD studies showed a linear relationship between acidity and VOC oxidation activity. In fact, a high concentration of weak acid sites is required for high toluene oxidation activity. The results can be explained in terms of a Mars–van Krevelen type of mechanism, involving the adsorption of toluene and its subsequent oxidation by lattice and/or surface oxygen. [ABSTRACT FROM AUTHOR]

The Ce 1− x Mn x O 2 nanocatalysts ( x = 0, 0.25, 0.50, 0.75 and 1.0 mol. ratio) were synthesized by precipitation method using a different precursor salt. The effect of morphology with exclusive (1 0 0) plane was examined for the selective oxidation of ethylbenzene into acetophenone with maximum selectivity. The physico-chemical properties of synthesized catalysts were characterized using various techniques. The incorporation of Mn n + into ceria lattice and the presence of (1 0 0) plane were confirmed by XRD and HRTEM analysis. The XRD patterns of Ce 1− x Mn x O 2 catalysts were analyzed using the Rietveld refinement method to calculate the lattice parameters. Surface area and pore size distribution of the catalysts were analyzed from N 2 sorption study. XPS and DR–UV–vis spectra confirm the presence of Ce 3+ and Mn 2+ in the ceria lattice. Further, the presence of Mn 2+ in Ce 1− x Mn x O 2 framework was confirmed from ESR technique. H 2 -TPR study revealed the oxygen storage capacity (OSC) of the catalysts. 3D flower-like and cubic morphology of ceria nanoparticles were confirmed from FESEM and HRTEM images, and the composition values of the elements present in the catalysts were calculated using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The catalytic activity was tested for vapor phase selective oxidation of ethylbenzene using oxygen as an oxidant at low temperature (463 K). The key reaction parameters were varied to study the stability, activity and selectivity of catalysts. The study concluded that suitable amount of manganese ion content in ceria is essential for selective oxidation of ethylbenzene at low temperature (463 K). Cubic structure Ce 0.25 Mn 0.75 O 2 nanocatalyst with specific (1 0 0) plane is found to be the most suitable catalyst for high conversion and selectivity toward acetophenone under the given reaction conditions. [ABSTRACT FROM AUTHOR]

The article presents the alloy phase diagrams for several binary systems including aluminum-magnesium (Al-Mg), bismuth-strontium (Bi-Sr) and cerium-copper (Ce-Cu). Tables that depict the crystal structure data of the binary systems are given. The criteria for the selection of information for inclusion in the supplemental literature review of the binary phase diagrams are also mentioned.

Fuel cladding chemical interaction (FCCI) has been a long-standing issue for the metallic fuel with a steel cladding in a sodium-cooled fast reactor, particularly for a high burnup fuel. Although the FCCI has been largely improved by alloying the fuels with Zr or Pd elements, applying a physical diffusion barrier between fuel and cladding, and employing advanced ferritic/martensitic (F/M) claddings, there is a scientific knowledge gap in understanding the behavior of chromium and its effects on the interdiffusion between lanthanides and advanced F/M steels that contain 9–12 wt.% Cr. In this paper, we systematically studied the interdiffusion between cerium and Fe–Cr model alloys with Cr contents of 6, 9 and 12 wt.%. Following the thermal annealing at 560 °C for up to 100 h, detailed microstructural characterizations were performed to determine the interdiffusion microstructures, compositional distributions, diffusion kinetics, and phase structures in the interdiffusion zone. This study unambiguously disclosed that, as the Ce diffuses into Fe–Cr model alloys, Cr segregates and precipitates into Cr-rich σ phase consisted of Fe and Cr instead of forming a ternary phase together with Fe and Ce. The precipitation of those nano-sized σ phase particles at the Ce diffusion front would effectively slow down the interdiffusion. [ABSTRACT FROM AUTHOR]

Short carbon fiber-reinforced p-type skutterudite CeFe 4 Sb 12 composites were fabricated by a melting-annealing process combined with spark plasma sintering, the effect of carbon fibers on the thermoelectric and mechanical properties were investigated, and the relationship between the microstructure and the mechanical properties of the composites were elucidated. The results indicate that the carbon fibers were well distributed throughout the matrix and were in intimate contact with the CeFe 4 Sb 12 grains without interlayers. Both the flexural strength and the fracture toughness of CeFe 4 Sb 12 were enhanced with the addition of the carbon fibers. Considering the tradeoff between the thermoelectric and mechanical properties, the optimal carbon fiber content was found to be 1 vol.%. The flexural strength of the composite containing 1 vol.% fiber was improved by 53%, whereas the fracture toughness and ZT value remained nearly unchanged. [ABSTRACT FROM AUTHOR]

We have found that Ce 3 Pd 20 As 6 crystallizes into a cubic C 6 Cr 23 -type structure. Combination of electron probe microanalysis of the chemical composition and Rietveld analysis of the powder X-ray diffraction pattern has revealed an inhomogeneous atomic composition of variable stoichiometry. The physical properties of Ce 3 Pd 20 As 6 were investigated by measuring the magnetization, electrical resistivity and specific heat. The 4 f electrons of Ce 3+ ions are well localized but do not show phase transition down to 0.5 K. The metallic electrical resistivity shows a weak Kondo screening. The residual resistivity ratio is rather low probably due to the variable stoichiometry. The magnetization curve and magnetic entropy suggest the Γ 8 quartet crystalline-electric-field ground state at least one of two Ce sites. [ABSTRACT FROM AUTHOR]

Part of the quaternary Ce–Mn–In–Ge phase diagram has been examined through powder X-ray diffraction and energy-dispersive X-ray analysis. Two new quaternary (Ce 4 Mn 2 InGe 4 and Ce 2 Mn 2 InGe 2 ) and two ternary (Ce 3 Mn 2 Ge 3 and Ce 43 Mn 18 Ge 39 ) phases were found. The isothermal sections of the boundary ternary systems (Ce–Mn–In, Mn–In–Ge, Ce–In–Ge, and Ce–Mn–Ge) were determined at 800 °C. Among these, the Ce–Mn–Ge system deserves particular attention because the phase equilibria are complex. Relative to the previously reported phase diagram evaluated at a lower temperature (400 °C), three ternary phases (CeMn 2 Ge 2 , Ce 2 MnGe 6 , and CeMnGe) persist, Ce 2 MnGe 5 does not form, and two new phases with very close composition (Ce 3 Mn 2 Ge 3 and Ce 43 Mn 18 Ge 39 ) appear at 800 °C. Ce 3 Mn 2 Ge 3 (orthorhombic Hf 3 Ni 2 Si 3 -type) has a small homogeneity range (2%) deviating from the ideal composition, whereas Ce 43 Mn 18 Ge 39 (tetragonal La 2+ x MnGe 2+ y -type) has negligible homogeneity. Magnetic measurements on Ce 4 Mn 2 InGe 4 suggest ferromagnetic behaviour. [ABSTRACT FROM AUTHOR]

A strategy is proposed to enhance the microstructure and mechanical properties of Mg–Zn alloys by combining microalloying additions of the rare earth element Ce and the non-rare earth element Ca. The double additions of Ce–Ca are found to significantly increase tensile elongation compared to binary Mg–Zn, or single additions of either Ce or Ca. Microstructure analysis reveals that the Ce–Ca additions increase ductility by modifying texture and refining grain size. Texture modification is attributed to solute effects from the microalloying elements, particularly Ca, while grain refinement is additionally influenced by a fine dispersion of Mg 6 Ca 2 Zn 3 precipitates that form during rolling and pin grain boundaries. The microalloying element additions also lead to large secondary phase particles in the alloys, which can limit ductility enhancement by promoting early fracture. By scaling Zn content in the Mg–Zn–Ce–Ca alloys, the Mg 6 Ca 2 Zn 3 phase fraction and Zn solute content can be controlled for optimum ductility or strengthening potential. [ABSTRACT FROM AUTHOR]

Copper–cerium–zirconium catalysts loaded on TiO 2 prepared by a wet impregnation method were investigated for NH 3 -selective catalytic reduction of NO x , aiming to study the effects of the Ce/Zr molar ratio on the performance of Cu–Ce–Zr/TiO 2 catalysts. The Cu–Ce 0.25 –Zr 0.75 /TiO 2 sample exhibited nearly 100% NO x conversion over a wide temperature range (165–450 °C), which is strikingly superior to that of Cu/TiO 2 (210–389 °C) within the range of exhaust temperatures of diesel engines. The factors that govern the activity enhancement were extensively investigated by using a series of characterization techniques, namely X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction by hydrogen (H 2 -TPR). The results showed that the addition of zirconium and/or cerium refined the copper dispersion, prevented copper crystallization and partially incorporated the copper ions into the zirconia (ceira) lattice, which led to enhance the redox abilities of Cu–Ce–Zr/TiO 2 catalysts. [ABSTRACT FROM AUTHOR]

To study the structural, electronic and thermodynamic behavior of CeMgTl, full-potential linear augmented plane wave plus local orbital (FP-LAPW + lo) method has been used. The lattice parameters ( a 0 , c 0 ), bulk modulus ( B 0 ) and its first order pressure derivative ( B 0 ′) have been calculated for CeMgTl. Band structure and density of states histograms depicts that “5 d ” orbital electrons of Tl have dominant character in the electronic contribution to CeMgTl. Impact of the temperature and pressure on unit cell volume, bulk modulus, Debye temperature, Grüneisen parameter, specific heat and thermal expansion coefficient ( α ) have been studied in wide temperature range (0–300 K) and pressure range (0–15 GPa). [ABSTRACT FROM AUTHOR]

ThMn 12 -type ternary cerium alloys with tetragonal structure (Pearson symbol tI26, space group I 4/ m m m) are considered as promising materials for permanent magnets. In this work, compositions of CeFe 11 X (s.g. P m m n , No. 59) and CeFe 10 X 2 (s.g. P 4/ m m m , No. 123) with all 3 d , 4 d , and 5 d transition metal substitutions are considered. Since many previous studies have focused on the CeFe 11 Ti compound, this particular case became the starting point of our considerations and we gave it special attention. We first determined the optimal symmetry of the simplest CeFe 11 Ti structure model. We then observed that the calculated magnetocrystalline anisotropy energy (MAE) correlates with the magnetic moment, which in turn strongly depends on the choice of the exchange–correlation potential. MAE, magnetic moments, and magnetic hardness were determined for all compositions considered. Moreover, the calculated dependence of the MAE on the spin magnetic moment allowed us to predict the upper limits of the MAE. We also showed that it does not depend on the choice of the exchange–correlation potential form. The economically justifiable compositions with the highest magnetic hardness values are CeFe 11 W, CeFe 10 W 2 , CeFe 11 Mn, CeFe 10 Mn 2 , CeFe 11 Mo, CeFe 10 Mo 2 , and CeFe 10 Nb 2. However, calculations suggest that, like CeFe 12 , these compounds are not chemically stable and could require additional treatments to stabilize the composition. Further alloying of the selected compositions with light elements embedded in interstitial positions confirms the positive effect of such dopants on hard magnetic properties. Subsequent calculations performed for comparison for selected isostructural La-based compounds lead to similar MAE results as for Ce-based compounds, suggesting a secondary effect of 4 f electrons. Our preliminary results obtained using the intra-atomic Hubbard repulsion term showed a relatively small difference for CeFe 12 compared to the results without this correction. Calculations were performed using the full-potential local-orbital electronic structure code FPLO18, whose unique fully relativistic implementation of the fixed spin moment method allowed us to calculate the MAE dependence of the magnetic moment. • Calculated magnetocrystalline anisotropy energy (MAE) correlates with magnetic moment. • MAE of CeFe 12 strongly depends on the form of exchange–correlation potential. • Upper limits of MAE for CeFe 12 -based alloys with transition metals are calculated. • Several candidates for new permanent magnets is predicted. • The observed effect of Ce 4 f electrons on the MAE values is secondary. [ABSTRACT FROM AUTHOR]