共查询到20条相似文献,搜索用时 31 毫秒
1.
《Journal of solid state chemistry》1987,69(1):186-188
ErBa2Cu3O7 and Er0.5Y0.5Ba2Cu3O7 are both high-Tc superconductors attaining zero resistance above 80 K. Preliminary studies indicate that Yb1−xYxBa2Cu3O7 also exhibits zero resistance above 77 K. 相似文献
2.
《Journal of solid state chemistry》1986,63(2):129-138
Two new oxyborate compounds were synthesized during a study of the phase relationships between the pinakiolite-ludwigite series of compounds. The structural topologies of these previously unreported materials have been determined experimentally by comparing calculated with observed electron microscope images. Both of these structures are very similar to each other, and also closely related to pinakiolite which consists of flat walls of edge-sharing octahedra connected to zigzag chains of octahedra by triangular BO3 groups. The two new structures contain similar infinite walls which are separated by slabs of octahedra that are wider than the zigzag chains found in pinakiolite. A new series of structurally related oxyborate compounds can be envisaged and are described. 相似文献
3.
Using different calorimeters, the following measurements have been carried out.
- 1.(i) The integral enthalpies of mixing of CeCu binary and some CeMgCu ternary liquid alloys,
- 2.(ii) The enthalpy of formation and the enthalpy of melting of the intermetallic compound CeCu2.
- 3.(iii) The heat content of solid and liquid CeCu2.
4.
《Journal of solid state chemistry》1987,71(2):562-565
A hypothetical oxygen pressure-composition phase diagram and a projection of the oxygen pressure-temperature-composition diagram on the composition triangle were constructed from phase equilibria in the system MnCrO on the basis of the data available in literature. The temperature-composition phase equilibrium diagram of this same system in air was specified. Isomorphism of solid solutions with spinel and hausmannite structure and their intertransformation was studied. Two chemical compounds, MnCr2O4 and Cr4Mn28O48, are supposed to exist in the system. 相似文献
5.
《European Journal of Solid State and Inorganic Chemistry #》1998,35(8-9):591-594
It has been found experimentally that phase diagram for the system Bi2O3CaOSrOCuO in SrO-rich region at 850°C in the open air includes three elementary tetrahedra: CaOSrOSr6Bi2O11Sr2CuO3, CaOSr2CuO3Sr6Bi2O11Sr3,5Ca0,5Bi2O7 and Sr3Bi2O6Sr6Bi2O11Sr3,5Ca0,5Bi2O7 Sr2CuO3. In the considered interval of corresponding oxide concentrations quaternary oxides are not formed under the above conditions. 相似文献
6.
7.
《Journal of solid state chemistry》1987,71(1):103-108
A systematic study of compound and solid-solution formation in the system Li2ONb2O5TiO2 has been made. Several solid-solution series, based on LiNbO3, LiNb3O8, Li2Nb28O71, Li2TiO3, phase M, Li2Ti3O7, and TiO2, have been characterized. In all cases, the principal solid-solution mechanism appears to involve stoichiometric formulae with constant overall cation content. One new phase, of approximate formula Li13TiNb5O21, has been prepared. A subsolidus phase diagram for the ternary system is presented. 相似文献
8.
The thermodynamic activities of liquid CuLa alloys were obtained at 1549 K by Knudsen effusion experiments. The experimentally known concentration and temperature dependences of thermodynamic properties of liquid CuLa alloys are explained on the basis of an association model. These results are discussed in comparison with the enthalpy of crystallization and the crystallization temperature as well as the enthalpy of melting and the melting temperature of lanthanum-rich glassy and crystalline alloys respectively. 相似文献
9.
10.
11.
12.
13.
《Journal of the Less Common Metals》1991,167(2):373-379
Thermodynamic measurements by the electromotive force method were made on the binary intermetallic phases URu3 and U3Ru5 and on the ternary carbides URu3C0.7 and U2RuC2 of the URu and the URuC systems between 950 and 1200 K using galvanic cells with CaF2 single crystal electrolytes: U, UF3¦CaF2¦UF3, URu3, Ru; U, UF3¦CaF2¦UF3, U3Ru5, URu3; Ru, URu3, UF3¦CaF2¦UF3, URu3C0.7, Ru, C; U, UF3¦CaF2¦UF3, URu3C0.7, U2RuC2, C. The Gibbs energies of formation of URu3, U3Ru5, URu3C0.7 and U2RuC2 were evaluated from the measured electromotive force which give fΔGo〈URu3〉 = −199 100 + 35.9 T J mol−1fΔGo〈U3Ru5〉 = −398 600 + 43.6 T J mol−1fΔGo〈URu3C0.7〉 = −192 600 + 2.5 T J mol−1fΔGo〈U2RuC2〉 = −380 200 + 52.5 T J mol−1 The implications of these thermodynamic data for the behaviour of the fission product ruthenium in irradiated carbide fuels are discussed. 相似文献
14.
《Journal of solid state chemistry》1987,71(1):61-69
The first systematic survey of the BaOReRe2O7 phase diagram is reported, with emphasis on the reduced ternary oxides. At 800°C, the previously reported compounds Ba3Re2O9, Ba2ReO5, and Ba3ReO6 were observed, all of which contain Re(VI) in ReO6 octahedra. The stability of these phases is apparently due to ReO π-bonding in and between the octahedra. The previously unknown structure of Ba2ReO5 was determined by powder neutron diffraction and found to be isotypic with that of K2VO2F3 (space group Pnma), with a = 7.3233(2), b = 5.7745(1), and c = 11.4124(2), Å. ReO6 octahedra share adjacent corners to produce cis chains which are held together by 10 coordinated Ba atoms. 相似文献
15.
《Solid State Sciences》2000,2(4):495-500
The polythermal diagram of the ternary system H2ONa2HPO4Na2SO4 has been established, setting up nine isotherms obtained between 0 and 25°C by conductimetric analysis. The solubility domains of the various solid phases have been determined. One eutectic, three stable and one metastable transitional transformations have been observed. Temperature and composition of the eutectic point have been obtained by thermal analysis at constant flow. 相似文献
16.
《Solid State Sciences》2000,2(4):489-493
The partial system Mg3(PO4)2Mg4Na(PO4)3Na4P2O7Mg2P2O7 in the ternary system MgONa2OP2O5 was investigated using thermal and X-ray diffraction analyses and microscopy, and its phase diagram has been determined. In this range of composition, two binary phosphates occur: Mg4Na(PO4)3 and Mg6Na8(P2O7)5. The former melts incongruently (at 1155°C) and the latter does congruently (at 808°C). In the partial system of interest, the two sections Mg4Na(PO4)3Mg2P2O7 and Mg4Na(PO4)3Mg6Na8(P2O7)5 are studied, and their phase diagrams are established. The partial system is divided into three partial ternary systems in which two ternary eutectics and one ternary peritectic occur. 相似文献
17.
NdFeB and corresponding MmFeB compounds were studied, the high field magnetization at 4.2 K, the a.c. susceptibility (4.2 < T < 300 K) and the anisotropy field were measured using the singular point detection technique (77 < T < 570 K). At room temperature the anisotropy field of the MmFeB is about 3T, whereas that of NdFeB compounds is about 7T. The MmFeB compounds showed effects due to the cerium (lowering the Curie temperature) as well as due to the neodymium (spin reorientation at low temperatures). 相似文献
18.
《Journal of solid state chemistry》1986,62(2):191-198
The extent of the glass forming region is described as a function of the composition and of the cooling speed. The shape of this region is explained from the previously described La2S3La2O3Ga2O3Ga2S3 phase diagram. Glasses are obtained after relatively slow cooling (5°/min), in a definite region of compositions, which coincides with a relatively large concentration of ternary invariants. The thermal properties (transition temperatures and crystallization temperatures) were measured by DTA. For a relatively large region of compositions, glasses return to the equilibrium conditions with intermediate formation of the La3.33Ga6S12O2 metastable crystalline phase. An approach to the structure of the glasses is made by comparison with the crystal structures of the numerous ternary and quaternary crystalline compounds observed in the system, and by the comparison of the Raman spectra. It appears that these gallium oxysulfide glasses have many structural analogies with germanium sulfide glasses. 相似文献
19.