Microstructure of the domain boundary and the effect of excess CuO in the melt-textured YBaCuO oxides

Kim, Chan-Joong; Kim, Ki-Baik; Kuk, Il-Hyun; Hong, Guang

doi:10.1016/0921-4534(95)00593-5

Cited by 20 publications

(16 citation statements)

References 29 publications

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“…According to our previous work [52] which surveyed the effect of excess CuO phase on the microstructure of melt-textured Y123, however, the excess CuO phase, which was included in the peritectic liquid phase, was not homogeneously distributed within the melt-textured Y123 domain when the liquid phase solidified. It was mainly concentrated at the domain boundaries of the Y123 in the form of the bulky CuO pool, the spherical CuO pockets, and the Y123/CuO cellular structure [52]. The amount of entrapped CuO in the interior of the Y123 domain-in particular, near the trapped Y211 inclusions-appears to be relatively small compared to that in the regions near the domain boundary.…”

Section: The Formation Mechanism Of the Stacking Faultsmentioning

confidence: 98%

“…This has led to the conclusion that the origin of the excess CuO phase lay in the CuO phase entrapped during high-temperature peritectic growth of the Y123 [10,[21][22][23]. According to our previous work [52] which surveyed the effect of excess CuO phase on the microstructure of melt-textured Y123, however, the excess CuO phase, which was included in the peritectic liquid phase, was not homogeneously distributed within the melt-textured Y123 domain when the liquid phase solidified. It was mainly concentrated at the domain boundaries of the Y123 in the form of the bulky CuO pool, the spherical CuO pockets, and the Y123/CuO cellular structure [52].…”

Section: The Formation Mechanism Of the Stacking Faultsmentioning

confidence: 99%

See 1 more Smart Citation

Microstructure of melt-textured Y - Ba - Cu - O oxides with addition and the formation mechanism of the Ba - Cu - O platelet structure

Kim

Park

et al. 1996

Supercond. Sci. Technol.

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Melt-textured YBa 2 Cu 3 O 7−y (Y123) containing fine particles of Y 2 BaCuO 5 (Y211) has been prepared from Y123/Y211 powder that was attrition milled with 1 wt% CeO 2 addition, and the microstructure has been examined. Fine and spherical Y211 particles (less than 1 µm in size) are found to be homogeneously dispersed within the melt-textured Y123 domain. Many dislocations are observed to be formed around the trapped Y211 and the Ba(Ce, Zr)O 3 inclusions, which were formed as a result of CeO 2 addition and ZrO 2 introduction from the ZrO 2 jar and ball used for attrition milling. CuO stacking faults were also observed around the trapped Y211; these were initiated at the Y123/Y211 interface and extended into the Y123 matrix. Each stacking fault has a lenticular shape, with a width of a few tens of nanometres and a length of a few hundred nanometres, and the faults developed along the [100] and [010] directions of the Y123. The formation mechanism of the stacking fault was discussed together with the formation of the platelet structure (the elongated Ba-Cu-O phase) on the basis of an oxygenation-induced decomposition of the Y123 phase. It is concluded that the prolonged oxygenation heat treatment producing the tetragonal-to-orthorhombic phase transformation is responsible for the formation of the platelet structure and possibly for the formation of the stacking faults.

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Section: The Formation Mechanism Of the Stacking Faultsmentioning

confidence: 98%

Section: The Formation Mechanism Of the Stacking Faultsmentioning

confidence: 99%

Microstructure of melt-textured Y - Ba - Cu - O oxides with addition and the formation mechanism of the Ba - Cu - O platelet structure

Kim

Park

et al. 1996

Supercond. Sci. Technol.

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“…Such a morphological change due to CeO 2 addition is similar to that observed in melttextured Y-Ba-Cu-O [29,30]. The formation of spherical pores and Y211-free regions was observed in the melt-textured Y-Ba-Cu-O system and can be explained by evolution of oxygen gas [31][32][33]. The formation of spherical pores is believed to be due to the oxygen gas evolution during incongruent melting which is associated with the change of the Cu-O valance state [31][32][33].…”

Section: The Effect Of Ceo 2 Addition On Sm211 Shapementioning

confidence: 61%

refinement via an attrition milling and addition in Sm-Ba-Cu-O systems melt-textured at oxygen partial pressures of 0.001 - 1 atm

Park

Kim

Lee

et al. 1996

Supercond. Sci. Technol.

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Sm 2 BaCuO 5 (Sm211) refinement was achieved in Sm-Ba-Cu-O systems melt-textured at various oxygen partial pressures (P O 2 of 0.001-1 atm) via 1 wt% CeO 2 addition and size control of a precursor powder (a mixture of SmBa 2 Cu 3 O 7−y (Sm123) plus Sm211 powder) by means of attrition milling. The resulting Sm211 of the Sm 1.8 Ba 2.4 Cu 3.4 O 7−y (Sm1.8) sample melt-textured without CeO 2 addition was as large as a few tens of µm while the Sm211 of the Sm1.8 sample melt-textured from the attrition-milled powder with 1 wt% CeO 2 addition was as small as 1-2 µm, with uniform Sm211 distribution. The Sm211 refinement achieved is ascribable to both the controlled Sm211 nucleation during incongruent melting and the growth inhibition of the Sm211 in the partial melting state. Furthermore, the Sm211 shape was changed from equiaxed granular in the undoped sample to anisotropic in the samples containing CeO 2 . Effects of oxygen partial pressure on the Sm211 size and the shape was not significant in either the undoped Sm1.8 sample and the CeO 2 -added Sm1.8 sample.

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“…F OR practical applications of bulk YBCO superconductors such as a flywheel and bearing system, a large-sized sample having a strong flux pinning force is needed. The melt-textured growth (MTG) technique [1]- [4] is known to be the most promising method of producing YBa Cu O superconducting materials with a high critical current density [5]- [9]. The addition of Y211 is beneficial to enhancement due to the enhanced pinning effect associated with the Y211/Y123 interfaces [10].…”

Section: Introductionmentioning

confidence: 99%

Effects of the platelet structures on the melt textured growth YBCO superconductors

Hong

Hwang

Han³

et al. 2003

IEEE Trans. Appl. Supercond.

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Microstructure of the domain boundary and the effect of excess CuO in the melt-textured YBaCuO oxides

Cited by 20 publications

References 29 publications

Microstructure of melt-textured Y - Ba - Cu - O oxides with addition and the formation mechanism of the Ba - Cu - O platelet structure

Microstructure of melt-textured Y - Ba - Cu - O oxides with addition and the formation mechanism of the Ba - Cu - O platelet structure

refinement via an attrition milling and addition in Sm-Ba-Cu-O systems melt-textured at oxygen partial pressures of 0.001 - 1 atm

Effects of the platelet structures on the melt textured growth YBCO superconductors

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