日本金属学会誌

J. Japan Inst. Metals, Vol. 52, No. 5 (1988),
pp. 441-447

Pretreatments and Sintering Behavior of Oxide Superconductors Y-Ba-Cu-O

Kazuhiro Kimura1, Akiyuki Matsushita2, Haruyoshi Aoki2, Shozo Ikeda1, Mitsuru Uehara1, Kin-ichi Honda2, Takehiko Matsumoto2 and Keiichi Ogawa1

1Tsukuba Laboratories, National Research Institute for Metals, Tsukuba
2National Research Institute for Metals, Tokyo

Abstract:

Sintering behavior of the high Tc oxide superconducting material, YBa2Cu3Oy, and its superconducting properties such as Tc and Jc have been studied. Particular attention has been paid to the mixing procedures of starting powders, the particle size of calcined powders, and the low temperature oxygen annealing.
In the calcined powder sintered for 3.1×105 s at 1203 K, most voids are annihilated, the grains are coarsened up to about 100 μ m in the long direction, and the density exceeds 90% of the ideal density. Full mixing of the starting powders considerably improves the density of sintered YBa2Cu3Oy, whereas ball milling of YBa2Cu3Oy powder degradates the improvement.
Resistivity of the sample in the normal conducting state increases with increasing sintering time, i.e. with increasing density; this behavior is attributed to difficulty in diffusing oxygen atoms into a high density YBa2Cu3Oy sample. Transmission electron microscope studies have often revealed the second phase along the grain boundary which is believed to reduce the critical current of polycrystalline bulk material YBa2Cu3Oy.


(Received 1988/1/19)

Keywords:

oxide superconductor, sinterability sintered density, critical temperature, critical current density, upper critical field, thin film, magnetic moment hysteresis loop, yttrium-barium-copper oxide, sintering condition


PDF(Free)PDF (Free)     Table of ContentsTable of Contents

Please do not copy without permission.