Effect of the cooling rate on the pore distribution in melt-processed YBa2Cu3O7–y superconductor

Jun, Byung‐Hyuk; Han, SC; Jeong, NH; Kim, C.-J.

doi:10.1016/j.physc.2007.02.018

Cited by 2 publications

(3 citation statements)

References 14 publications

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“…As can be seen in sample (a), large pores of a few tens of microns are observed. Their size and shape are the same as those reported in the conventional melt process [7][8][9] and are quite different from the pores (1-2 µm in size and a faceted shape) as observed in the sintered Y211-Ag pre-forms of figure 4(e). It is worth mentioning that the pore size gradually decreases as the sintering temperature for the Y211-Ag pre-form increased.…”

Section: Methodssupporting

confidence: 64%

“…The pores of a spherical shape are believed to be formed by oxygen gas evolution during melting of Y-123 powders [7]. Many pores tend to be captured in the Y-123 grains, particularly in the core of the Y-123 products [9]. Compared with the sample interior, however, the sample surface is very dense.…”

Section: Introductionmentioning

confidence: 99%

“…The lower pore density in the surface regions is considered to be due to the easier diffusion of the oxygen gas through the sample surfaces. The pores developed in the sample core are as large as about a few hundred microns in size due to several pores coalescing in the melt, depending on the applied heating cycles [9]. The incongruent melting of a Y-123 powder accompanied by the release of oxygen gas is given by the equation below [7]: where s, l and g denote solid, liquid and gas, respectively.…”

Section: Introductionmentioning

confidence: 99%

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Effective pore control and critical current density in liquid infiltration growth processed Y-123 superconductors with Ag addition

Mahmood

Jun

Han

et al. 2010

Supercond. Sci. Technol.

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The effect of a sintered density (open porosity) of Y 2 BaCuO 5 (Y211) pre-forms on the final porosity and Y211 size within YBa 2 Cu 3 O 7−y (Y-123) products was systematically studied in liquid infiltration growth (LIG) processed Y-123 bulk superconductors with Ag addition. To prepare Y211 pre-forms of various densities, Y211 powder compacts were sintered in air at various temperatures of 900-1200 • C. The single-grain Y-123 bulk superconductors were fabricated by the LIG process with top seeding. It was found that the porosity of the final Y-123 product was fairly dependent on the Y211 pre-form density. When a Y211 pellet of a high density was used as a pre-form for the LIG process, the porosity of the final Y-123 product was greatly reduced. In addition to the reduced porosity, the enhanced Y211 refinement was achieved for the Y-123 product prepared using the dense Y211 pre-form, resulting in the improved critical current density (J c ). The Ag addition was also helpful in eliminating the spherical pores through pore filling with a silver melt. The pore elimination and Y211 refinement mechanism in the LIG-processed Y-123 bulks were explained in terms of the liquid capillary movement and Ag melt and particle coarsening at the (Y211 + melt) state.

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Section: Methodssupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%