Jun ZOU
,
Shengming ZHOU
材料科学技术（英文）
About Φ45 mm LiAlO2 single crystal was grown by Czochralski (Cz) technique. However, the full-width at half-maximum (FWHM) value was high to 116.9 arcsec. After three vapor transport equilibration (VTE) processes, we can obtain high-quality LiAlO2 slice with the FWHM value of 44.2 arcsec. ZnO films were fabricated on as-grown slices and after-VTE ones by pulsed laser deposition (PLD). It was found that ZnO films on the two slices have similar crystallinity, optical transmittance and optical band gap at room temperature. These results not only show that LAO substrate is suitable for ZnO growth, but also prove that the crystal quality of LAO substrate slightly affects the structural and optical properties of ZnO film.
关键词:
Crystal structure
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null
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null
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null
Xing LU
,
Zuoxiang QIN
,
Xing TIAN
,
Yansheng ZHANG
,
Bingzhe DING
,
Zhuangqi HU
材料科学技术（英文）
The influences of lattice parameter of austenite, the electron concentration, the yield strength of parent phase on γ→ε martensite start temperature MS in the Fe-Mn alloys containing C, Al, Ge and Si have been experimentally investigated. The results show that the lattice parameter of austenite is more important than the electron concentration and the yield strength of parent phase in governing the γ→ε martensitic transformation in Fe-Mn based alloys. A relation between the MS and lattice parameter of austenite in Fe-Mn based alloys is suggested. The elements Mn, C, Al, Ge, which increase the lattice parameter of austenite lower the MS while the element Si, which decreases the lattice parameter increases the MS. The depressing effect of antiferromagnetic transition on the γ→ε martensitic transformation may be related to the increase of lattice parameter due to the positive magnetostriction during the antiferromagnetic transition.
关键词:
Crystal structure
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null
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null
Y. Zhang
,
D.J. Wen
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null
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null
金属学报(英文版)
Ni3+ and Cr3+ doped Fe-Mn-Co-Cu-O spinels were prepared by solid phase sintering. The valence states and distribution of transition ions in the spinel crystals are being inferred from the consideration of thermodynamic principle and crystalline field theory. The microstructure and performance of those are studied by XRD, FT-IR and IRE-2 infrared radiant instrument. Ni3+ and Cr3+ occupy the vacancies or substitute the other ions in the spinel structure and formed diverse spinel structure, which exhibits infrared integral emissivities of 0.93 in the whole bands, and 0.94 in the bands within 14~25μm too. The content of Fe2O3 and MnO2 in the spinel crystals changes maybe induces infrared radiativity of spinels differently.
关键词:
Crystal structure
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null
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null
Lei Miao
,
Sakae Tanemura
,
Thi Hue Nguyen
,
Li Luo
,
Masaki Tanemura
,
Shoichi Toh
,
Kenji Kaneko
,
Masahiro Kawasaki
材料科学技术（英文）
An alternative sol-gel method has been applied to fabricate anatase and rutile TiO2 coatings uniformly on Al scale fibers with very thin naturally oxidized layer from mixed precursors of Ti tetraisopropoxide, acetyl acetone, deionizer water and ethanol in different molar ratios. The crystal structure of TiO2 coatings on Al scale fiber was confirmed by both XRD and TEM. The surface morphology of the coatings was observed by SEM and the chemical composition of the grown TiO2 was analyzed by EDS in TEM. Anatase coating, having a fine crystalline structure, was grown at 450℃ while rutile was being done at 670℃. The TEM results indicated that the fabricated TiO2 coatings consisted of anatase/rutile polycrystalline structures. The optimal fabrication conditions for TiO2 coatings with about 400 nm in thickness on Al scale fibers were established through the characterization results.
关键词:
Sol-gel method
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null
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null
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null
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null
A.A.El-Meligi
材料科学技术（英文）
Al-alloy (AA5022) corrosion penetration (CP) and crystal structure were investigated after running static immersion corrosion tests in 1 mol/L HCl solution and different concentrations of rare earth elements (La3+), (Ce3+) and their combination, at different temperatures. X-ray diffraction (XRD) was used to examine the surface structure before and after immersion, and secondary electron detector (SED) was operated to study surface morphology. In 1 mol/L HCl solution the corrosion penetration increased with increasing temperature and immersion time. The increase of La3+ concentrations up to 1000×10-6 g/L led to the decrease in the corrosion penetration, and the decrease in Ce3+ concentrations up to 50×10-6 g/L decreases the corrosion penetration of the alloy. Mix3 (combination of La3+ and Ce3+) dramatically reduced the corrosion penetration. This suggests that a synergistic effect exists between La3+ and Ce3+. The reaction kinetics both in absence and presence of La3+ and Ce3+ and their combination would follow a parabolic rate law. The XRD patterns revealed that the intensities of certain hkl phases are affected. The crystalline structure has not been deformed either before or after testing and there are no additional peaks except that of the as-received alloy. In the case of accelerating CP, the surface morphology shows that the roughness and voids of surface are increased.
关键词:
Al-alloy
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Corrosion
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penetration
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Crystal
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s
Hai JING
,
Hong GUO
,
Shuguang ZHANG
,
Zili MA
,
Shaoming ZHANG
材料科学技术（英文）
The fine structure of hydrogen storage alloy powders MlNi4.3-xCoxMn0.4Al0.3(x=0.75, 0.45, 0.10; Ml: La-rich misch metal) prepared by rapidly solidifying gas atomization was investigated using a Rietveld analysis method. Two sets of CaCu5-type crystal constants were observed in the studied alloys and one set was larger than the other. With decreasing powder radius the solidification rate of powder increased, and so did the percentage of a particle part with larger crystal constants. The reason why there were two sets of crystal constants might be the difference of solidification rate between the outside and inside of a particle.
关键词:
Hydrogen storage alloys
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null
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null
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null
Jihui WANG
材料科学技术（英文）
MoS2 coatings were prepared using an unbalanced bipolar pulsed DC (direct current) magnetron sputtering apparatus under different targets, cathode current densities, power modes and bias voltages. The morphology, structure and growth characteristics of MoS2 coatings were observed and identified respectively by scanning electron microscopy, X-ray diffractometry and mass spectrometry. The results show that MoS2 coatings evolve with the (002) basal plane parallel to the surface by using cold pressed target with lower density, lower cathodic current density, bipolar pulse DC power and minus bias voltage, whereas the coatings deposited under hot pressed target, higher cathodic current density, simple DC power and positive bias voltage have the (002) basal plane perpendicular to the surface. The influence of deposition conditions on the crystal structure of MoS2 coating is implemented by altering its growth rate and the energy of sputtering-deposition particles.
关键词:
Deposition condition
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null
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null
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null
Bingshe XU
,
Peide HAN
,
Jian LIANG
,
Yuan YU
,
Huiqiang BAO
,
Xuguang LIU
材料科学技术（英文）
The structure of potassium hexatitanate (K¬¬2T¬6O¬13) nanowires has been investigated using both the Rietveld powder diffraction profile fitting technique and high resolution transmission electron microscopy (HRTEM) image simulations. From the Rietveld analysis it was shown that the nanowires had a monoclinic structure of the space group C2/M and the lattice parameters were a=1.5582 nm, b=0.382 nm, c=0.9112 nm. HRTEM conclusions agree with refinement results obtained from experimental XRD data. The good agreement between the experimental and simulated images confirms that the nanowires is indeed K¬¬2T¬6O¬13 nanowire.The growth axes of nanowires were mainly along the [010] direction.
关键词:
Potassium hexatitanate
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null
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null
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null
Hu Wang Juan Xie Kangping Yan Ming Duan
材料科学技术（英文）
Different morphologies of zinc oxide (ZnO), including microrods, hexagonal pyramid-like rods and flower-like rod aggregates, had been synthesized, respectively, on glass substrates by controlling the reaction conditions (such as precursor concentration, reaction time and pH value) of hydrothermal method. The morphologies of the as-obtained ZnO were observed with scanning electron microscopy and transmission electron microscopy.
Also, the crystalline natures of di®erent ZnO crystals were analyzed with X-ray diffraction. The possible growth mechanism of ZnO crystals with di®erent morphologies was discussed.
关键词:
Zinc oxide
Zhiqing YUAN
,
Guanglie LU
,
Bin LIAO
,
Yongquan LEI
材料科学技术（英文）
Structural analysis was made using X-ray diffraction (XRD) Rietveld refinement on a series of La1+xMg2-xNi9 (x=0.02~1.0) ternary alloys. Results showed that each of La1+xMg2-xNi9 alloys was a PuNi3-type structure stacked by LaNi5 and (La, Mg) Ni2 blocks. Electrochemical tests revealed that discharge abilities of these La-Mg-Ni ternary alloys mainly depended on their atomic distances between (La, Mg) and Ni, which could be modified by varying the atomic ratios of La/Mg.
关键词:
Hydrogen storage alloy
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null
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null
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null
