| 摘要 |
PURPOSE:To improve critical current density by specially controlling the composition of repsective components, the state of dispersion, and heat treatment conditions, respectively, at the time of producing a Y-Ba-Cu-O type oxide superconducting material. CONSTITUTION:RE (where Re means Y, La, Nb, etc.), Ba, and Cu elements in the whole raw material are regulated so that they are in a mole ratio of 1:(1 to 2):(1 to 3), and >=30 mol% of RE is allowed to be present in the form of RE2BaCuO5 of <=5mum mean grain size. Further, Pt and/or Rh element is mixed uniformly with the raw material by 0.005-5wt.%, and the resulting mixture is compacted. Subsequently, after heating is carried out to a temp. in a region where RE2BaCuO5 phase and liquid phase coexist, cooling is performed down to the lower limit temp. Tp of this temp. region at 0.2-1000 deg.C/h cooling rate. Further, cooling is carried out through the temp. region from the above temp. to (Tp-40 deg.C) at 0.2-10 deg.C/h cooling rate, followed by further cooling carried out to a room temp. Then, oxygen enrichment treatment is carried out by means, e.g. of holding in an oxygen-enriched atmosphere at 600-200 deg.C for 2-200hr, by which the RE-Ba-Cu-O type oxide superconducting material can be obtained. |
