Infiltration and Top Seed Growth‐Textured YBCO Bulks With Multiple Holes

Abstract

The recently reported hole‐patterned YBa2Cu3Oy (Y123) bulks with improved superconducting properties are highly interesting from material quality and application variety points of view. It is well known that the core of plain bulk superconductors needs to be fully oxygenated and some defects like cracks, pores, and voids must be suppressed in order that the material can trap a high magnetic field or carry a high current density. To minimize the above defects, we have used a combination of standard superconducting ceramic processing and an infiltration technique to prepare regularly perforated YBa2Cu3Oy (Y123) bulk superconductors. This process leads to negligible shrinkage upon annealing and a uniform distribution of Y211 inclusions. Texture was evidenced by neutron pole figure measurements. Flux mapping was used to verify the superconducting homogeneity of the samples and to investigate the field‐trapping ability. In addition, the textured drilled samples were reinforced using resin or metal impregnation and the influence of the different processing steps on the hardness of the materials has been investigated.

Improvement of Critical Current Density and Flux Trapping in Bulk High-Tc Superconductors

“…The network of the holes has not affected the current loops at the large scale. This result was confirmed by the neutron diffraction measurements (D1B line at ILL, France) showing [52] only one single domain bulk orientation with mean c-axes parallel to the pellet axis. The trapped field value is higher in the perforated pellet (583 mT) than in the plain one (443 mT).…”

“…The same trapped field of 250 mT before and after impregnation has been measured. Presently, it is important to develop the specific shapes of bulk superconductors with mechanical reinforcement [52] for any practical application. Multiple holes or porous ceramic materials, such as alumina and zirconia, are established components in a number of industrial applications such as inkjet printers, fuel injection systems, filters, structures for catalysts, elements for thermal insulation and flame barriers.…”

A Novel Configuration for Infiltration and Growth of Single‐Domain Gd–Ba–Cu–O Bulk Superconductor

“…R ecently , the infiltration and growth (IG) process, used for fabrication of single‐domain (here, a single domain is defined as a quasi‐single‐crystal containing many imperfections or defects) RE–Ba–Cu–O (REBCO) bulks, is attracting considerable attention because of its advantages compared with the conventional melt growth method, such as fewer pores, cracks and distortions, insignificant shrinkage in the final products, especially the homogeneous distribution of fine RE 2 BaCuO 5 (RE‐211) particles in the REBa 2 Cu 3 O 7− x (RE‐123) matrix 1–9 . For this process, as schematically shown in Fig.…”

Fabrication of Large Gd–Ba–Cu–O Single Domains with Different Liquid Sources

“…However, the heavy loss of liquid and collapse of the sample have been observed when the Ba 3 Cu 5 O 8 (035, i.e., a mixture of BaCuO 2 and CuO powders in a molar ratio of BaCuO 2 :CuO=3:2) powder was used as a liquid source, especially when the liquid source was supplied rather richly. As a result, a mixture of RE‐123 and Ba 3 Cu 5 O 8 is usually used as the liquid source in the IG process, 5–7 and the above two cases can be effectively avoided with the support of solid RE‐211 particles decomposed from the starting RE‐123 phase at high temperature, and hence it could be seen that three kinds of precursor powders, involving RE‐211, RE‐123, and BaCuO 2 , have to be prepared for the IG process.…”