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1.
LaB6-ZrB2共晶复合材料的组织特征及控制 总被引:2,自引:0,他引:2
用电弧炉和电子束悬浮区熔炉法制备了LaB6ZrB2共晶复合材料,并用SEM和TEM方法对其显微组织进行了研究。结果表明,LaB6ZrB2形成纤维状共晶组织,控制凝固条件可得到定向排列的组织,LaB6基体上均匀分布着直径为02~12μm的ZrB2纤维,纤维长度可达100μm以上。对于固液界面为平面生长的试样,其结晶学取向关系为[001]LaB6∥[001]ZrB2,(110)LaB6∥(010)ZrB2。 相似文献
2.
Electrosynthesis of hafnium diboride from cryolite-alumina melts containing hafnium and boron oxides
S. V. Devyatkin 《Russian Journal of Electrochemistry》2005,41(4):392-394
Electrosynthesis of hafnium diboride from cryolite-alumina melts containing hafnium and boron oxides is studied. Thermodynamic estimation and voltammetric measurements show this process to occur in one-stage. Hafnium diboride coatings on nickel are obtained by electrolysis.__________Translated from Elektrokhimiya, Vol. 41, No. 4, 2005, pp. 448–451.Original Russian Text Copyright © 2005 by Devyatkin. 相似文献
3.
Intikhab A. Ansari 《Physica C: Superconductivity and its Applications》2010,470(22):2078
Here, I present the reply to the comments from Mamedov regarding numerical solution of Bloch–Gruneisen function to determine the contribution of electron–phonon interaction in polycrystalline superconductor. Reply to the comments from Mamedov is discussed one by one. 相似文献
4.
Highly c-axis oriented MgB2 thin films with Tc^onset of 39.6K were fabricated by magnesium diffusing into pulsedlaser-deposited boron precursors.The estimation of critical current density Jc,using hysteresis loops and the Bean model,has given the value of 10^7A/cm^2(15K,0T),which is one of the highest values ever reported.The x-ray photoemission study of the MgB2 thin films has revealed that the binding energies of Mg 2p and B 1s are at 49.4eV and 186.9eV,which are close to those of metallic Mg and transition-metal diborides,respectively. 相似文献
5.
H? TiO or TiB2? – A Correction Reinvestigations of “H? TiO” single crystals and the comparison with measurements of TiB2 crystals have shown that “H? TiO” in fact is titanium diboride. 相似文献
6.
《Mendeleev Communications》2023,33(1):138-140
Vanadium diboride was directly synthesized by borothermal reduction of V2O5 with the addition of epoxy resin as a reducing agent for the low-temperature reduction of vanadium(V) to vanadium(IV), which leads to the gradual removal of oxygen by the formation of CO gas. The slow rate of gas release prevents destruction of green body, which usually occurs during conventional borothermal reduction. This makes it possible to directly obtain VB2 powder with an average particle size of 200–300 nm without need to prepare intermediate lower vanadium oxides. 相似文献
7.
Titanium diboride ultrafine powder was prepared from sucrose, tetrabutyl titanate and boric acid by the sol–gel and microwave
carbothermal reduction method. The influence of reaction temperature, ratio of Ti to C and Ti to B on the synthesis of titanium
diboride was studied. The results indicated that the carbothermal temperature, the content of carbon and the amount of H3BO3 show obvious effects on the formation of TiB2. 1,300 °C was the optimum synthesis temperature and pure TiB2 could be prepared. The microstructure of prepared TiB2 was investigated by field emission-scanning electron microscopy (FE-SEM), which results showed that the crystalline size
of the prepared titanium diboride at 1,300 °C was about 3–5 μm. The quantities of the crystalline phases of the powders prepared
at different temperatures were analyzed by Rietveld refinement method.
An erratum to this article can be found at 相似文献
8.
G. Levchenko A. Lyashchenko A. Evdokimova Yu. Paderno 《Journal of solid state chemistry》2006,179(9):2949-2953
ScB2 single crystals were grown by inductive floating zone melting. The ScB2 structure was refined on single crystal and powder data, the latter obtained from parts of single crystals which were prepared by controlled crushing. The ScB2 structure corresponds to the AlB2 structure type, sp. gr. P6/mmm, No. 191 (R1=0.0191, wR2=0.0474), lattice parameters are equal to a=0.314820(3) nm, c=0.351483(5) nm, c/a=1.117, X-ray density is 3.670 g/cm3. The measured hydrostatic density is 3.666 g/cm3 which correspond to the Sc0.99B2 composition. The ScB2 Young modulus value is equal to 480 GPa and the Debye characteristic temperature is 1020 K. 相似文献
9.
We present critical comments on the recent paper [Intikhab A. Ansari, Physica C: Superconductors, 470 (2010) 508] concerning numerical methods for solving Bloch–Gruneisen function and its applications to MgB2 superconductor. It is demonstrated that the presented in this work the formulas and examples are not original and they are quite identical the formulas already established in our article [B.A. Mamedov, I.M. Askerov, Physics Letters A, 362 (2007) 324]. 相似文献
10.
Ulrich Burkhardt Vladimir Gurin Frank Haarmann Walter Schnelle Yuri Grin 《Journal of solid state chemistry》2004,177(2):389-394
Single crystals of aluminum diboride (space group P6/mmm, No. 191) a=3.0050(1) Å, c=3.2537 (8) Å; Z=1) were prepared by the aluminum flux method. Crystal structure refinement shows defects at the aluminum site and resulted in composition Al0.894(9)B2≈Al0.9B2. The defect structure model is confirmed by the measured mass density ρexp=2.9(1) g/cm3 in comparison with a calculated value ρx=3.17 g/cm3 for full occupancy of the aluminum position. The results of 11B NMR measurements support the defect model and are in agreement with the structure obtained by X-ray diffraction methods. Electrical resistivity measured on a single crystal parallel to its hexagonal basal plane with ρ(300 K)−ρ(2 K)=2.35 μΩ cm shows temperature dependence like a typical metal. Charge is dominantly carried by holes (Hall-coefficient R=+2×10−11 m/C). Respective, p-type conductivity is confirmed by theoretical calculations. Chemical bonding in aluminum diboride is discussed using the electron localization function. 相似文献