Crystal Chemistry and Phase Equilibrium Studies of the BaO(BaCO3)-1/2R2O3-CuOx Systems in Air: VI, R = Neodymium

Autor: Winnie Wong-Ng, Boris Paretzkin, Judith K. Stalick, Michael D. Hill, Lawrence P. Cook
Rok vydání: 1994
Předmět:
Zdroj: Journal of the American Ceramic Society. 77:2354-2362
ISSN: 1551-2916
0002-7820
DOI: 10.1111/j.1151-2916.1994.tb04605.x
Popis: Crystal chemistry and subsolidus phase equilibrium studies of the Ba-Nd-Cu-O system near the CuO and Nd2O3 corners have been carried cut at 950°C in air. Two solid-solution series have been identified in the Ba-Nd-Cu-O system. The first series involves the high-Tc superconductor phase, and has the formula Ba2–xNd1+xCu3O6+z, where × < ≅ 0.7. At the ideal compound stoichiometry of Ba2NdCu3O6+z, the transformation from the high-Tc orthorhombic to tetragonal phase occurs at 550°–575°C in air. This temperature varies as a function of composition, and at x≅ 0.2 to 0.3 it occurs at 950°C. The second solid solution is the non-superconducting “brown phase” represented by Ba2+2x-Nd4–2xCu2–xO10–2z 0 ≤x≤ 0.1. Preliminary phase diagrams of the BaO–Nd2O3 and Nd2O3–CuOx systems are also presented. Standard X-ray diffraction patterns of BaNd2–CuO5 and (Nd1.9Ca0.1)CuO4–z are provided.
Databáze: OpenAIRE
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