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A new Ca1/3Sb1/6Bi1/2PO4 “CaSb0.50Bi1.50(PO4)3” phosphate has been synthesized by conventional solid-state reaction techniques at 900 °C in air atmosphere. Their crystallographic structures were determined at room temperature from X-ray powder diffraction (XRPD) data using the Rietveld analysis. CaII1/3SbV1/6BiIII1/2PO4 material possesses the high-temperature BiPO4 monoclinic structure variety. It crystallizes in monoclinic system with P21/m space group and the cell parameters are: a = 4.9358(1) Å, b = 6.9953(2), c = 4.7075(1) Å, and β = 96.2(1)°. Their structure can be described as composed of alternating edge-sharing AO8 (A = Ca, Sb, Bi) bisdisphenoids and PO4 tetrahedra forming chains parallel to the b axis. Every AO8 polyhedron is surrounded by six PO4 and every PO4 tetrahedron is surrounded by six AO8 polyhedra. Infrared spectroscopic study was used to obtain further structural information.
The effect of a strong magnetic field on the solid solubility and the microsegregation during directional solidification of Al–Cu alloy at lower growth speeds (1–10 μm/s) has been investigated experimentally. Results indicate that the magnetic field causes the reduction of the grain boundary and promotes the amalgamation of the grains. Further, measurement results reveal that the magnetic field increases the solid solubility and decreases the microsegregation. It is also found that the value of the solid solubility increases as the magnetic field and the temperature gradient increase. The modification of the solid solubility and the microsegregation under the magnetic field is attributed to the thermoelectric magnetic force acting on the solid and the interdendritic thermoelectric magnetic convection. The present work may initiate a new method to enhance the solid solubility and to eliminate the microsegregation in Al-based alloys via an applied strong magnetic field during directional solidification.
The compound 2-ethyl-6-(pyridin-4-yl)-7H-indeno[2,1-c]quinoline (2) (chemical formula C23H22N2) was synthesized through the free-solvent oxidation reaction mediated by elemental sulfur from the corresponding 2-ethyl-6-(pyridin-4-yl)-5,6,6a,11b-tetrahidro-7H-indeno[2,1-c]quinoline (1), an adduct easily obtained, using the Lewis acid-promoted [4 + 2] cycloaddition reaction. Preliminary molecular characterization was performed by Fourier transform-infrared and gas chromatography-mass spectrometry. The X-ray powder diffraction (XRPD) pattern for the title compound was analyzed and found to be crystallized in monoclinic system, space group P21/n (N° 14) with refined unit-cell parameters a = 20.795 (8) Å, b = 7.484 (2) Å, c = 10.787 (2) Å and ß = 93.96° (2). The volume of the unit cell is V = 1674.8 (6) Å3.
The dichlorodioxido(4,4′-dimethoxycarbonyl-2,2′-bipyridyl)molybdenum(VI) complex was prepared from molybdenum(VI) dichloride dioxide and 4,4-dimethoxycarbonyl-2,2-bipyridyl in CH2Cl2 obtaining a clear green solution. The molybdenum complex was separated by precipitation with ethyl ether. The XRPD pattern for the new compound showed that the crystalline compound belongs to the monoclinic space group P21/c (No 14) with refined unit-cell parameters a = 12.104(1) Å, b = 14.933 (2) Å, c = 11.010 (2) Å and ß = 115.409° (9). The volume of the unit cell is V = 1797.6 (3) Å3.
Experimental X-ray powder diffraction data, unit-cell parameters, and space group for norethindrone, C20H26O2, are reported [a = 20.7484(12) Å, b = 12.1678(9) Å, c = 6.5561(2) Å, α = β = γ = 90°, unit-cell volume V = 1655.17(16) Å3, Z = 4 and space group P212121]. All measured lines were indexed and are consistent with the P212121 space group. No detectable impurity was observed.
The advanced quenching and partitioning (Q&P) heat treatment has been applied to 9Cr–1.8W–0.3Mo heat resistant steel. The phase transformation during Q&P is measured by a high-resolution differential dilatometer by which the accurate information can be obtained. The transmission electron microscope examination was conducted to study the microstructure evolution after Q&P, and the refined carbon-enriched martensite laths, which were produced during the second martensitic transformation, were observed. The thermodynamics of carbon partitioning was described by a paraequilibrium model according to which the partitioning of carbon from martensite into austenite can be proved. A kinetic model for the second martensitic transformation was developed with the parameters discussed in details. The retardation of onset and end temperature of the second martensitic transformation can be ascribed to the austenite stabilization caused by carbon enrichment.
Compound effects of B and Y additions on the microstructures and properties of a new type of high-strength and high-conductivity (HSHC) Cu–Mg–Te alloys are investigated on the aspects of purification and precipitation. Because of the purification function of B and Y additions, the tensile strength increased superlatively by the amplitude of 21.7% with a similar increase of elongation and the electrical conductivity of 4.2%. By comparison of the calculated decomposition pressures of B2O3 and Y2O3 at different temperatures, it can be concluded that the boron oxide is more stable than the yttrium oxide in the copper liquid, indicating the superior deoxygenization purification of the rare earth yttrium. The dispersive distribution of the Y–B compounds (YB6) was another factor for the improvement of the mechanical properties of the copper alloy. Finally, the copper alloy treated by hot rolling, cold rolling, and annealing processes in sequence exhibits HSHC with the tensile strength of 610.7 MPa and the electrical conductivity of 53.1%IACS.
Cu(In,Ga)Se2 (CIGS) semiconductors were prepared by arc melting and the vacuum solid reaction. CIGS nanoparticles were synthesized by the mechanical alloy method. The influences of various ball-milling speeds on phase structures for CIGS nanoparticles were investigated by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The crystal structures and unit-cell parameters of CIGS nanoparticles were determined using TREOR program and the least squares method. A Rietveld structural refinement was used to determine the atomic occupations and atomic numbers of CIGS prepared under various ball-milling speeds. The least size of agglomerated CIGS nanoparticles should be around 200 nm. CIGS nanoparticles milled at various milling speeds with a tetragonal chalcopyrite structure were obtained according to XRD analyses. However, Ga content in CIGS depends on milling speeds. Based on the structural refinements, the unit-cell parameters are a = 5.693(8)–5.744(9) Å and c = 11.334(9)–11.524(4) Å with gallium content ranging from 0.3 to 0.5. The atomic occupations are corresponding to the 4a crystal site for Cu atoms, the 4b site for In and the 8d site for Se. Ga prefers to occupy the 4b crystal site.
In order to complete the research on the Fe–Se binary system, the phase structures with selenium contents from 50 to 60 at.% have been studied. Fe–Se binary samples used in this study were prepared by the high-temperature solid-state reaction method, and the phase structure of each sample was determined by powder X-ray diffraction. The solid solubility of the Fe3Se4 phase was determined to be from 56.1 to 57.6 at.% Se based on the values of unit-cell parameters. Magnetic properties of the samples were also studied.
The c-oriented La1.8Sr0.2CuO4 and La1.9Sr0.1CuO4 bilayer films were deposited on (001) SrTiO3 single-crystal substrates by using the pulsed laser deposition technique. The effects of deposition parameters on the quality of thin films were investigated. The crystal structures and surface morphologies were characterized by means of XRD and SEM, and the results showed that an as-prepared film deposited with the optimized parameters has high quality. Then La1.8Sr0.2CuO4/La1.9Sr0.1CuO4 bilayers structure was prepared using the optimized parameters for each corresponding layer, and the electrical transport properties were measured. Interesting rectifying properties were observed at both room and low temperatures, and the rectifying ratio at low temperature was found to be much higher than that at room temperature.
Nanostructuring is one of the effective approaches to lower the thermal conductivity of thermoelectric materials for improving its figure of merit. The nano-sized uniform skutterudite Co1−xNixSb3 (x = 0, 0.05, 0.075, 0.125, 0.15, and 0.25) thermoelectric powders were synthesized in triethylene glycol solution by using CoCl2, NiCl2, and SbCl3 as precursors and NaBH4 as the reductant. Different synthesis conditions were studied to pursue pure and uniform skutterudite CoSb3 powders. The powders were characterized by X-ray diffraction, field emission scanning electron microscope, and energy-dispersive X-ray analysis. Experimental results show that a Ni-doped skutterudite Co1−xNixSb3 single phase was obtained at 290 °C for 12 h. The powders are spherical, small, and uniform. As x increases from 0 to 0.25, the unit-cell parameter a increases from 0.9044 to 0.9065 nm and the particle size increases from 10 to 30 nm.
Ni nanowire arrays were prepared by electroplating using anodic aluminum oxide templates, and a magnetic field was applied during the electroplating process. The effects of an applied magnetic field on the texture and magnetic properties of the Ni nanowire arrays were studied. The results show that the (110) texture is formed in the nanowires prepared in different magnetic fields. However, the applied magnetic field during electroplating can affect the texture degree, and there exists a suitable magnetic field for small diffusion degree of the (110) texture. On the basis of texture characterization, the effects of applied magnetic field on the magnetic properties of Ni nanowire arrays are discussed.
Investigations into the morphology and structural evolvement of nanomaterials are essential for understanding the growth process. Herein, we present meaningful results on crystallinity transformation of β-SiC nanorods at different preparation temperatures using X-ray diffraction. Results of the characterization indicated that both crystallinity and yield of the as-prepared β-SiC nanostructures were enhanced with increasing reaction temperature. Scanning electron microscope and high-resolution transmission electron microscope were further employed to understand detailed structural information of the SiC nanorods obtained at specific temperature. The results may shed light on structural evolvement for fabrication of nanomaterials.