Showing papers on "Solid solution published in 2010"
TL;DR: In this paper, a nanosized ceria-lanthana (CL) solid solution has been synthesized by a modified coprecipitation method, and the structural and redox properties have been deeply investigated employing various characterization techniques, namely, X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM), Raman spectroscopy (UV-RS and Vis-RS), UV-visible diffuse reflectance spectroscope (UVvis DRS), and temperature programmed reduction (TPR).
Abstract: The catalytic CO oxidation results revealed that nanosized ceria-lanthana (CL) solid solution exhibits superior catalytic performance and thermal stability in comparison to ceria-zirconia (CZ) solid solution. The rationale for excellent catalytic behavior of the CL sample was elucidated from the viewpoint of structure, redox behavior, and bulk oxygen mobility. Accordingly, in this investigation CL solid solution has been synthesized by a modified coprecipitation method, and the structural and redox properties have been deeply investigated employing various characterization techniques, namely, X-ray diffraction (XRD), BET surface area, transmission electron microscopy (TEM), Raman spectroscopy (UV-RS and Vis-RS), UV-visible diffuse reflectance spectroscopy (UV-vis DRS), and temperature programmed reduction (TPR). The catalytic efficiency has been evaluated for oxygen storage/release capacity (OSC) and CO oxidation activity. The analyses of the characterization results provided a deep insight on the physica...
242 citations
15 Oct 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the effect of Mo element on the structure and properties of AlCoCrFeNi alloy was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscope (TEM), and differential scanning calorimeter (DSC).
Abstract: Multicomponent AlCoCrFeNiMo(x) (x values in molar ratio, x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5) alloys were prepared using a well-developed copper mould casting. The effects of Mo element on the structure and properties of AlCoCrFeNi alloy were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and differential scanning calorimeter (DSC). It was found that Mo addition took significant effects on the structure and properties of AlCoCrFeNi alloy. Mo(0.1) alloy, similar to Mo(0) alloy, was of single BCC solid solution structure. When Mo content was more than 0.1, the alloy exhibited a typical laminar eutectic structure. The alloy strength was improved obviously, but the ductility of alloy was lowered at the same time. The maximum yield strength reached 2757 MPa when Mo content was 0.5, and the maximum compressive fracture strength reached 3208 MPa when Mo content was 0.3. The strengthening effect and mechanism of Mo addition on AlCoCrFeNi alloy were discussed from different aspects. (C) 2010 Elsevier B.V. All rights reserved.
212 citations
15 Feb 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, the synthesis of nanocrystalline equiatomic CuNiCoZnAlTi high entropy alloy by mechanical alloying and characterized by XRD, SEM and TEM is described.
Abstract: The present study describes the synthesis of nanocrystalline equiatomic CuNiCoZnAlTi high entropy alloy by mechanical alloying and characterized by XRD, SEM and TEM. The CuNiCoZnAlTi high entropy alloy is mainly composed of BCC solid solution with crystallite size less than 10 nm in as milled condition. The alloy is thermally stable at elevated temperature about 800 °C as it retained its nanostructure. This alloy powder was consolidated using vacuum hot press at 800 °C with 30 MPa pressure to a density of 99.95%. The hardness and compressive strength of the high entropy alloy are found to be 7.55 and 2.36 GPa, respectively. Superior strength of high entropy alloy is attributed to solid solution strengthening and its nanocrystalline nature.
208 citations
TL;DR: In this article, a series of Cd 1− x Zn x S solid solutions were synthesized at 80°C with the assistance of sodium dodecylsulfate, and the structures, optical properties and morphologies of the solid solutions have been studied by X-ray diffraction, UV-vis diffuse reflectance spectroscopy, and transmission electron microscopy.
207 citations
TL;DR: In this article, the equiatomic multiprincipal CoCrFeNiCuAl high-entropy alloy was prepared using a vacuum arc melt casting method and the as-cast alloy was subsequently annealed at 1000°C for 2h and the annealing effects on the structure and properties evolution were investigated.
183 citations
TL;DR: In this paper, high-temperature stable three-dimensional spongelike mesoporous Ce x Zr 1− x O 2 solid solutions consisting of nanometer size particles with different Ce/Zr compositions were synthesized by a modified sol-gel procedure using a triethanolamine/water mixture as a solvent to be used in liquid Knoevenagel condensation reaction.
173 citations
TL;DR: A facile, high-energy mechanical milling (HEMM) approach has been developed to synthesize carbon-coated olivine LiM1−yMyPO4 (M = Fe, Mn, Co, and Mg) solid solution nanoparticles.
Abstract: A facile, high-energy mechanical milling (HEMM) approach has been developed to synthesize carbon-coated olivine LiM1−yMyPO4 (M = Fe, Mn, Co, and Mg) solid solution nanoparticles. A systematic structural and electrochemical characterization of the solid solution series has been carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), charge−discharge measurements, and galvanostatic intermittent titration technique (GITT). The discharge capacity, voltage profile, and cycle performance of the LiM1−yMyPO4 solid solution cathodes are found to be dependent on the different redox couples involved in the reaction. Equilibrium potentials obtained from GITT and dQ/dV plot reveal a systematic shift in the redox potential of Fe2+/3+, Mn2+/3+, and Co2+/3+ couples in the LiM1−yMyPO4 solid solution compared to their pristine end members (LiMPO4). The shifts in the redox potential are explained on the basis of the changes in the covalency of the M−O bond and M−O−M interaction, and the consequent change...
165 citations
TL;DR: In this paper, the phase diagram of (1−−x)(Bi0.5Na 0.5)-SrTiO3 was completed and investigations on polarization and strain in this system were carried out.
Abstract: The phase diagram of (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3 was completed and investigations on polarization and strain in this system were carried out. (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3-ceramics were prepared by conventional mixed oxide processing. The depolarization temperature (Td), the temperature of the rhombohedral–tetragonal phase transition (Tr–t) and the Curie temperature (Tm) were determined by measuring the temperature dependence of the relative permittivity. All solid solutions of (1 − x)(Bi0.5Na0.5)TiO3–xSrTiO3 show relaxor behavior (A-site relaxor). From XRD-measurements a broad maximum of the lattice parameter can be observed around x = 0.5 but no structural evidence for a morphotropic phase boundary was found. SEM-analysis revealed a decrease of the grain size for increasing SrTiO3-content. At room temperature a maximum of strain of about 0.29% was found at x = 0.25 which coincides with a transition from a ferroelectric to an antiferroelectric phase. The temperature dependence of the displacement indicates an additional contribution from a structural transition (rhombohedral–tetragonal), which would be of certain relevance for the existence of a morphotropic phase boundary.
164 citations
25 Oct 2010-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing
TL;DR: In this article, a non-metallic Si element is introduced to AlCoCrFeNiSi(x) alloys and the improvement of mechanical properties is attributed to the solid solution of Si element and precipitation strengthening of nanoscale cellular structure.
Abstract: By introducing nonmetallic Si element, AlCoCrFeNiSi(x) (x values in molar ratio, x = 0, 0.2, 0.4, 0.6, 0.8 and 1.0) alloys are designed and prepared. One kind of nanoscale cellular structure forms due to the introduction of nonmetallic Si element. The alloy is composed mainly of BCC solid solution and possesses excellent room-temperature compressive mechanical properties. The excessive introduction of Si element leads to the precipitation of 8 phase at grain boundary. The improvement of mechanical properties is attributed to the solid solution of Si element and precipitation strengthening of nanoscale cellular structure. The precipitated 8 phase at grain boundary should be responsible for transition of alloy from plastic fracture to brittle fracture. Among them, Si(0.4) alloy exhibits excellent comprehensive mechanical properties, yield stress of 1481 MPa, fracture strength of 2444 MPa and plastic strain of 13.38%, respectively. (C) 2010 Elsevier B.V. All rights reserved.
160 citations
TL;DR: In this paper, the microstructure characterization of four as-cast CoCrFeNiAl 0.3, CoCr FeNiTi0.3 and CoCrfeNiAl0.1 alloys is presented, and the formation of L12 ordered nanoparticles should fulfill the criteria of alloy composition having both more than 25.25
149 citations
TL;DR: The photoluminescence intensity of ZnS-AgInS(2) solid solution nanoparticles was remarkably enhanced by increasing the heating temperature to 180 degrees C, above which the emission was simply diminished, while ZNS coating of the particles resulted in further enhancement of PL intensity, giving the highest quantum yield.
TL;DR: In this paper, the effect of elemental interaction on microstructure of these alloys is investigated by means of Ni equivalent and Cr equivalent, and the formation of simple solid solution phase is associated with the slight difference in atomic size and properly mixing enthalpy.
TL;DR: In this article, the authors report experimental partition coefficients for Se, Te, As, Sb, and Bi between monosulfide solid solution (mss) and sulfide melt, determined at 950°C at a range of sulfur fugacities (fS2) bracketed by the Fe 1−×S−Sx equilibria.
TL;DR: The effects of milling duration and subsequent annealing on the structure and morphology evolution were investigated in this paper, where the equiatomic multicomponent CoCrFeNiTiAl high-entropy solid solution alloy was synthesized by mechanical alloying.
TL;DR: In this paper, three kinds of complex oxides oxygen carriers (CeO2-Fe2O3, CeO2−ZrO2 and ZrO 2-TPR and Raman) were prepared and tested for the gas-solid reaction with methane in the absence of gaseous oxidant.
TL;DR: In this article, X-ray diffraction and temperature-programmed reduction (TPR) analyses of the more intense diffraction peaks and cell parameter measurements showed formation of La-Sr-Ni-Co-O solid solutions with La 0.9 Sr 0.1 CoO 3 and La 2 O 3 as the main crystallographic phases present on the solids depending on the degree of substitution.
TL;DR: In this article, material synthesis was realized by magnetron sputter epitaxy of thin films starting from optimal conditions for the formation of w-AlN onto lattice-matched w-alN seed layers on Al2O3(0001) and MgO(111) substrates.
Abstract: AlN(0001) was alloyed with ScN with molar fractions up to ∼22%, while retaining a single-crystal wurtzite (w-) structure and with lattice parameters matching calculated values. Material synthesis was realized by magnetron sputter epitaxy of thin films starting from optimal conditions for the formation of w-AlN onto lattice-matched w-AlN seed layers on Al2O3(0001) and MgO(111) substrates. Films with ScN contents between 23% and ∼50% exhibit phase separation into nanocrystalline ScN and AlN, while ScN-rich growth conditions yield a transformation to rocksalt structure Sc1−xAlxN(111) films. The experimental results are analyzed with ion beam analysis, x-ray diffraction, and transmission electron microscopy, together with ab initio calculations of mixing enthalpies and lattice parameters of solid solutions in wurtzite, rocksalt, and layered hexagonal phases.
TL;DR: From the measurements of hydrogen pressure-composition isotherms and solid-state (2)H NMR, it is revealed that Ag-Rh solid-solution alloys absorb hydrogen, and the total amount of hydrogen absorbed reached a maximum at the ratio of Ag:Rh = 50:50, where the electronic structure is expected to be similar to that of Pd.
Abstract: Rh and Ag are the neighboring elements with Pd that is famous for a hydrogen-storage metal. Although Rh and Ag do not possess hydrogen-storage property, can Ag–Rh alloys actually storage hydrogen? Ag–Rh solid-solution alloys have not explored in the past because they do not mix each other at the atomic level even in the liquid phase. The author has used the chemical reduction method to obtain such the Ag–Rh alloys, and XRD and STEM-EDX give clear evidence that the alloys mixed at the atomic level. From the measurements of hydrogen pressure-composition isotherms and solid-state 2H NMR, The author has revealed that Ag–Rh solid-solution alloys absorb hydrogen and the total amount of hydrogen reached a maximum at the ratio of Ag:Rh = 50:50, where the electronic structure is expected to be similar to that of Pd.
TL;DR: In this paper, the photocatalytic activity of a series of TiO 2 powders was assessed in gas phase and the results were explained by taking into account the anatase and rutile relative amounts in the samples, their crystallite size, the surface hydroxyl groups adsorbed on the photocats, and the surface area of the mixtures.
Abstract: A series of TiO 2 –SiO 2 mixtures – having the following stoichiometry Ti 1− x Si x O 2 , with x = 0, 0.1, 0.3 and 0.5 atoms per formula unit – were prepared by using precursor oxides and fired at three temperatures (900, 1000 and 1200 °C). The modifications in the structure and, consequently, on the photocatalytic activity, induced by the addition of SiO 2 into the TiO 2 powder, were thoroughly investigated by using various analytical techniques: X-ray powder diffraction, electron microscopy (FE-SEM and TEM), XPS, FT-IR, DRS and BET analysis. The results underlined as essentially no solid solution occurs between the two crystalline end-members. Nevertheless, silica addition caused a retarding effect on anatase-to-rutile phase transformation and on the crystallite growth. The photocatalytic activity of the powders was assessed in gas phase and the results were explained by taking into account the anatase and rutile relative amounts in the samples, their crystallite size, the surface hydroxyl groups adsorbed on the photocatalysts and the surface area of the mixtures.
TL;DR: The thermoelectric performance of EuZn(1-x)Cd(x))(2)Sb( 2) with the CaAl(2]Si(2)-type crystal structure (space group Pm1) was optimized by mixed occupation of the transition metal position to show low electrical resistivity, high thermopower and a low lattice thermoconductivity.
Abstract: The thermoelectric performance of EuZn2Sb2 and EuCd2Sb2 was optimized by mixed occupation of the transition metal position. Samples in the solid solution Eu(Zn1−xCdx)2Sb2 with the CaAl2Si2-type crystal structure (space group m1) were prepared from the elements for compositions with x = 0, 0.1, 0.3, 0.5 and 1. The thermoelectric properties were investigated after densification of the products by spark plasma sintering (SPS). The samples show low electrical resistivity, high thermopower and a low lattice thermoconductivity. The highest ZT value of 1.06 at 650 K is obtained for x = 0.1.
TL;DR: In this paper, a nano-structured and homogeneous Cu-Cr powder mixture was mechanically alloyed in order to study the solid solubility extension during the alloying process.
TL;DR: In this paper, a multiphase Mo-Si-B alloys containing a Mo solid solution matrix and brittle Mo3Si and Mo5SiB2 (T2) intermetallic phases are evaluated.
TL;DR: In this article, the ionic and p-type conductivities have been determined, as well as the activation energy in wet reducing atmospheres, in which protonic conduction is dominant.
TL;DR: In this paper, the effects of annealing treatments on the microstructure, elastic and mechanical properties of a bulk glassy rod was investigated, and the different microstructural mechanisms responsible for these annesaling-induced changes in mechanical and elastic properties were discussed.
Journal Article•
TL;DR: In this paper, the transformation from β- to α-quartz-solid-solution was studied by dilatometry, X-ray diffraction and transmission electron microscopy.
TL;DR: In this article, a detailed X-ray Photoelectron Spectroscopy (XPS) analyses were performed on the surfaces and on the fractured sintered bodies. And the maximum magnetization was observed for x ǫ = 0.05, which might represent the proper range of compositions for multiferroism at room temperature.
TL;DR: In this article, the stability of various crystallographic phases of (1−x)BiFeO3-xPbTiO3 as a function of composition and temperature was studied and the structure of BF-xPT was reconfirmed to be tetragonal and monoclinic in the P4mm and Cc space groups.
Abstract: In this report, we have studied the stability of various crystallographic phases of (1−x)BiFeO3–xPbTiO3 as a function of composition and temperature. The structure of BF-xPT is reconfirmed to be tetragonal and monoclinic in the P4mm and Cc space groups for x>0.31 and 0.10≤x≤0.27, whereas the two phases coexist in the morphotropic phase boundary (MPB) region 0.27
TL;DR: In this article, the authors demonstrate the possibility of preparing solid solutions in the (MgGa2O4)x(MgFe2O 4 )1 − x system by pyrohydrolytic and solid-phase methods.
Abstract: This work demonstrates the possibility of preparing solid solutions in the (MgGa2O4)x(MgFe2O4)1 − x system by pyrohydrolytic and solid-phase methods. It is shown that the products obtained have different specific surface areas depending on the ratio between metal nitrates and citric acid. The composition dependence of the unit cell parameter deviates considerably from the Vegard’s rule. The compounds obtained are found to be stable up to 300°C, which makes them candidate materials for electronics.
TL;DR: Pd-based LaFeO3 perovskite type catalysts have been prepared by the amorphous citrate method with the aim to expose Pd at the surface of La FeO3 and to force Pd to form a solid solution.
Abstract: Pd-based LaFeO3 perovskite-type catalysts have been prepared by the amorphous citrate method with the aim to expose Pd at the surface of LaFeO3 (Pd/LaFeO3) and to force Pd to form a solid solution