Effect Of Sm Addition Research Articles

Effect of Sm Addition on the Electrochemical Behavior and Discharge Performance of Mg-1Sn-1Ca-0.3Mn Alloy as Mg-Air Battery Anodes

Sm element is a relatively inexpensive rare Earth element. The effect of Sm content on the microstructure, electrochemical behavior and discharge performance of Mg-1Sn-1Ca-0.3Mn (TX11) alloy was investigated through scanning electron microscopy (SEM), electrochemistry workstation and Mg-air battery tests. Results reveal the addition of Sm does not change second-phase morphology of TX11 alloy, CaMgSn and Mg2Ca phases solidly dissolves Sm elements. The electrochemistry results depict that Sm addition deteriorates the corrosion resistance and electrochemical activity of TX11 alloy, which is attributed to Sm solid solution changing the original second phase properties. In addition, Mg-1Sn-1Ca-0.5Sm-0.3Mn anode presents the highest anodic efficiency and specific capacity among Mg-1Sn-1Ca-xSm-0.3Mn (x = 0. 0.5, 1, 2 wt%) alloys, those value is 60.2% and 1306.801 mA h g−1, respectively, which attribute to the highest dissolution activity and the smoother discharge surface morphology. Micro-Sm alloyed is beneficial for improving the anodic efficiency of TX11 anode.

Effect of Sm addition on the microstructure and mechanical properties of Mg–xSm–0.4Zr alloys

Effect of Sm addition on the microstructure and tensile properties of as-extruded Mg–xSm–0.4Zr (x = 1, 2, 3, 4 wt.%) alloys have been investigated by optical microscopy, scanning electron microscopy, X-ray diffraction, electron backscatter diffraction and transmission electron microscope. The results indicat that all the extruded alloys exhibit a fully dynamically recrystallized (DRXed) microstructure. When the Sm content exceeds 3 wt.%, the as extruded sheet dynamic precipitate the Mg41Sm5 particles during hot extrusion. Sm addition could refine the grain size and weaken the texture of the as-extruded alloy, significantly enhance the strength and ductility of the as-extruded alloy. When the Sm content is 3 wt.%, the alloy sheet displays a good balance of strength and ductility. The Mg–3Sm–0.4Zr sheet shows YS and UTS of 144.5 MPa and 280.7 MPa along ED, the YS and UTS are 163.8 MPa and 280.7 MPa for 45°and 192 MPa and 283.9 MPa for TD. The ε along the ED, 45°and TD are 22.3%, 21.6% and 19.8%, respectively. The dominant strengthening mechanisms include grain boundary strengthening, solid solution strengthening and precipitation strengthening.

Effects of Sm addition on microstructure evolutions and mechanical properties of high-strength Mg–Gd−Sm–Zr extruded alloys

Effects of various Sm additions on microstructures and mechanical properties of a hot-extruded Mg–14Gd−0.5Zr alloy were studied in this work. The results indicate that Sm addition firstly clearly improves the strength and then decrease as the Sm content increases at both room temperature and high temperatures. The highest yield strength was obtained to be ∼495 MPa and ∼512 MPa under tension and compression, respectively, at room temperature with the Sm concentration of 1 wt% while those were to be 384 MPa and 248 MPa at 250 °C and 300 °C, respectively, with the Sm content of 0.5 wt%. Electron backscatter diffraction mappings reveal that Sm addition significantly promotes dynamic recrystallization, resulted in much more fine recrystallized grains and lower texture intensity. Furthermore, transmission electron microscopy observations show that Sm addition increases dynamic precipitates particularly in non-recrystallized regions, leading to relatively less aging precipitates during artificial peak-aging. Finally, discussion based on grain boundary strengthening and dispersion strengthening suggests that Sm addition improving the yield strength of the extruded Mg–14Gd−0.5Zr alloy is mainly attributed to more grain boundaries and dynamic precipitates at room temperature and high temperatures, respectively.

The effect of Sm addition on structure, redox properties and catalytic activities for water gas shift reaction of ceria-based support

Oxygen vacancy in ceria-based support is a dominate factor for catalyzing the water gas shift reaction by faster a redox cycle between Ce4+ and Ce3+ which is one of the elementary step in WGS reaction mechanism. Therefore, in this work, CeO2-based support was incorporation by Sm ion in order to produce the oxygen vacancy defect site. Ce1-xSmxO2 (x = 0.010, 0.050, and 0.10 at%) mixed oxide supports were synthesized by urea gelation to investigate the role of Sm addition into ceria-based support on surface, structural and redox properties which was altered to their catalytic activities. XRD and Raman spectroscopy results indicated the incorporation of Sm3+ into CeO2 lattice which gave rise to unit cell enlargement and led to structural distortions inside CeO2 which produced strain and unbalanced charge and then finally facilitated oxygen vacancy formation. XANES and EXAFS results also evidenced the replacement of Sm3+ into Ce4+ site in CeO2 lattice. H2-Temperature programmed reduction and temperature-resolved X-ray absorption spectroscopy (under reduction condition) were employed to investigate the reducibility of Ce1-xSmxO2 supports. XANES spectra of Ce L3 edges displayed lower surface reduction temperature (Ce4+ to Ce3+) which corresponded to H2-TPR results. The results of catalytic activity tests for water gas shift reaction showed that the activity of 1 wt%Pd/Ce1-xSmxO2 was higher than that of 1 wt%Pd/CeO2. The role of Sm on enhancing WGS reaction rate were to increase CO molecules adsorption by promoting the dispersion of active metal site on catalyst surface and to facilitate the redox cycle between Ce4+ and Ce3+ of ceria support by oxygen vacancies formation. Therefore, combined these two effects the WGS activities were enhanced. Moreover, by using the results from our previous works together with the results from this work, we can evidence that speeding up the different elementary steps in the reaction mechanism, the WGS rate can also be enhanced.

Effect of Samarium (Sm) Addition on the Microstructure and Tensile Properties of Al–20%Si Casting Alloy

In the present work, the effect of Sm addition (0.2, 0.4, 0.6, and 0.8 wt%) on the microstructure evolution and tensile properties of as-cast hypereutectic Al–20%Si alloy were investigated. The scanning electron microscopy, X-ray diffraction (XRD), and electron probe microanalysis with wavelength dispersive spectroscopy (WDS) were used to quantitatively characterize the samples. The results indicated that the primary Si phases were significantly refined from coarse polygonal and star-like shape to fine block with smooth edges and corners when the addition of Sm increased from 0 to 0.6%. Furthermore, eutectic Si phases were fully modified from coarse platelet-like/needle-like structure to fine fibrous structure and discrete particles with the addition of 0.6%Sm. However, the primary and eutectic Si phases became coarser when the level of rare earth Sm reached 0.8%. The analysis of XRD and WDS shows that Sm mainly exists in the form of Al2Si2Sm compounds. In addition, the tensile properties of as-cast Al–20%Si alloy with different concentrations of Sm were investigated by tensile test. It was found that the ultimate tensile strength (UTS) and elongation (EL) gradually enhanced with the increasing concentration of Sm from 0 to 0.6% due to decrease of the size and the change of morphology on Si phases. Compared with unmodified Al–20%Si alloy, the UTS and EL values of Al–20%Si alloy with 0.6%Sm were increased by 48.5 and 68.8%, respectively.

The Effect of Sm Addition on the Microstructure and Superconducting Properties of YBCO Bulk Superconductors

The Effect of Sm Addition on the Microstructure and Superconducting Properties of YBCO Bulk Superconductors

YBCO Bulk Superconductors with Sm Addition

The influence of Sm addition on the microstructure and superconducting properties of Y-Ba-Cu-O (YBCO) bulk superconductors has been studied. Precursor powders YBa2Cu3O7-δ (Y-123), Y2O3 and CeO2 were enriched with different amounts of SmBa2Cu3Oy (Sm-123) or Sm2O3 powders with the aim to increase critical current density, Jc,by introducing additional pinning centers. YBCO bulk superconductors with SmBa2Cu3Oy (Y123-Sm) or Sm2O3 (Y123-SmO) powder addition were prepared by the optimized top seeded melt growth process in the form of single grains. Microstructure analysis revealed that Sm2O3 addition leads to a higher amount of smaller Y2BaCuO5 (Y-211) particles, what is related to high critical current densities (Jc ~ 7 x 104 A/cm2) of the YBCO samples with Sm2O3 addition in low magnetic fields. The effect of Sm addition in the form of SmBa2Cu3Oy as well as Sm2O3 powder on Y2BaCuO5 particle size, critical temperature, Tc, and critical current density, Jc, is reported.

Modification of eutectic silicon and β-Al5FeSi phases in as-cast ADC12 alloys by using samarium addition

The effects of Sm additions (0, 0.5 wt.%, 1.0 wt.% and 1.5 wt.%) on the eutectic Si and β-Al5FeSi phases of ADC12 as-cast alloys were studied by optical microscopy (OM), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The experimental results showed that Sm was an effective modifying agent for the eutectic Si of ADC12 alloy, when 1.0 wt.%–1.5 wt.% Sm was added to the alloy, the coarse acicular eutectic Si was modified into fine particle or short rod structure. Moreover, the appropriate addition of Sm (about 1.0 wt.%) had marked effects on shortening the length of needle-like β-Al5FeSi phase. Whereas, Sm was less effective on modifying the needle-like β-iron to the Chinese script or spherical α-iron phase. The modification mechanism was also discussed.

Phase transition and electric field induced strain properties in Sm modified lead zirconate stannate titanate based antiferroelectric ceramics

The effect of Sm addition on the crystal structures and electrical properties of Pb1−3x/2Smx(Zr0.63Sn0.26Ti0.11)O3 ceramics were investigated in this work. X-ray diffraction analysis showed that with increasing Sm content from 0.005 to 0.03, the phase structure of the specimens underwent transition from ferroelectric (FE) to antiferroelectric (AFE) state due to the substitution of Sm3+ with smaller ion radius for Pb2+ decreasing the tolerance factor of the ceramics. In addition, it was observed that with the improvement of Sm3+ content, the strain of the specimens first increased and then decreased, and the largest value of 0.735% was obtained in the sample with x = 0.015 near AFE/FE phase boundary at the measuring frequency 1 Hz. This is because the reversal of the domains, which produces the strain, is more consummate in this composition. Further, the strain at different frequencies was nearly the same at high electric field, which was attributed to that the electric field applied to the sample was so large that the reorientation of the domains could finish in all measuring frequencies. Both a high strain level and a relatively good frequency stability in the specimen with x = 0.015 make a potential candidate for actuators applications over a wide-frequency working range.

Microstructure and Mechanical Properties of Mg-Al-Ca-Sm Alloys at High Temperature

The aims of this research are to investigate the effect of Sm addition in Mg-Al-Ca alloys on microstructure and mechanical properties. Sm addition to Mg-5Al-3Ca based alloys results in the change from dendritic to equiaxed grain morphorlogy and formation of Al-Sm rich itermetallic compounds at grain boundary and α-Mg matrix. And these Al-Sm rich intermetallic compounds were dispersed homogeously and stabilized at high temperature. And maximum yield and ultimate strength value was obtained at Mg-5Al-3Ca-2Sm alloys at elevated temperature because of homogeneous dispersion of stable Al-Sm rich intermetallic compound at high temperature.

Effect of Sm addition on (Bi,Pb)-2212 superconductor

The effect of Sm addition on the superconducting properties of (Bi,Pb)-2212 system in bulk polycrystalline form was studied. The Sm content was varied from x = 0.0 (pure) to 0.5 on a general stoichiometry of Bi 1.7Pb 0.4Sr 2.0Ca 1.1Cu 2.1Sm x O y . Phase analysis by XRD, microstructural examination by SEM equipped with energy dispersive X-ray spectrometer (EDS), density measurements and superconductivity characterizations were done to evaluate the relative performance of the samples. Critical current density ( J c) and superconductivity transition temperature ( T c) of Sm added samples were found to be higher than that of the pure sample, i.e. without Sm added. A maximum J c of 719.4 A/cm 2 at 64 K was measured for the SM2 sample which is more than seven times higher than that of the pure sample ( J c = 94.1 A/cm 2). Also the T c of the SM3 sample was the highest (94.1 K) compared to all other samples. Microstructural examination showed distinct variations in the grain morphology of the samples containing Sm. A Sr-rich oxide containing Pb(Bi) and Cu with square rectangular grains with rounded edges was observed in the microstructure of Sm added samples whose composition has been analysed through EDS. But such a secondary phase could not be distinguished from XRD analysis probably due to the peak overlapping with (Bi,Pb)-2212.

Effect of Sm Addition on Ni–MgO Catalysts for the Synthesis of Carbon Nanotubes via Methane Decomposition

Abstract Carbon nanotubes (CNTs) have been synthesized over Ni–MgO and Ni–Sm–Mg catalysts by decomposition of CH4 at 923 K. The addition of Sm into Ni–MgO catalyst promotes its catalytic activity and lifetime. The yield of CNTs obtained over the optimized Ni–Sm–Mg catalyst reaches 1260 wt % relative to the weight of the catalyst, which is more than 4 times that of the Ni–MgO catalyst. The possible interaction between Sm and Ni species is discussed.