SEM studies on BSCCO superconducting ceramic produced by spray frozen, freeze drying technique

Bunescu, M. C.; Aldica, G.; Badica, P.; Vasiliu, F.; Niţă, P.; Mandache, S.

doi:10.1016/s0921-4534(97)00633-3

Cited by 5 publications

(9 citation statements)

References 17 publications

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“…Some of the (Sr 0.13 Ca 0.87 ) 1.1−1.5 CuO x grains contain a small amount of Bi and/or Pb. Sr-Ca-Cu-O grains with Bi and/or Pb were also detected in pellets produced by the conventional sintering of freeze-dried or oxide/carbonate precursor powders [5,26]. The cation ratio between Ca and Sr for the 14:24-phase has been determined by calculations from XRD measurements using data given in [27].…”

Section: Sem and Eds Investigationsmentioning

confidence: 99%

“…The XRD composition for 14:24phase is (Ca 0.71 Sr 0.29 ) 14 Cu 24 O 41+x , which is consistent with the EDS result. After HT of sample 5, SEM and EDS data (table 2) indicate specific microstructure (plate-like, intergrowth of crystals [5]) and crystal compositions for the 2223-phase (figure 4).…”

Section: Sem and Eds Investigationsmentioning

confidence: 99%

“…Further research is needed to optimize the 2223-RFAST synthesis and processing. For comparison, the best samples obtained in air after 70 h of HT from the same freeze-dried precursor powder without RFAST consist of 50-60% of 2223-phase [5].…”

Section: And Table 2)mentioning

confidence: 99%

“…Previous efforts have been focused on the synthesis of Bi(Pb)-2223-phase using nano-nitrate precursor powder obtained by the spray frozen, freeze-dried technique [2][3][4][5][6][7][8][9][10]. We have recently proposed a new route for the superconducting 2223-phase synthesis of dried powder in non-isothermal 3 Author to whom correspondence should be addressed.…”

Section: Introductionmentioning

confidence: 99%

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Reactive-field-assisted-sintering of freeze-dried powders in the BSCCO system

Badica

Aldica

Groza

et al. 2001

Supercond. Sci. Technol.

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The reactive-field-assisted-sintering technique (RFAST) has been applied to freeze-dried decomposed precursor powders with a starting cation composition of Bi:Pb:Sr:Ca:Cu = 1.7:0.3:2.0:2.5:3.5. A short time (<15 min) RFAST treatment at 800-900 • C did not lead to the formation of Bi 2 Sr 2 Ca 2 Cu 3 O 10+x (2223-phase). But RFAST was favourable to Bi 2 Sr 2 CaCu 2 O 8+y (2212-phase) formation particularly in samples with a low content of the 2212-phase in the precursor powder. Heat treatment (HT) after RFAST showed that the 2223 phase could form more rapidly than in freeze-dried pressed and sintered pellets produced by the traditional technique. The resultant ceramics after 70 h of annealing contain 75% 2223-phase and have T c(R=0) = 100.7 K, T c = 109.5 K and T c = 22.4 K.

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Section: Sem and Eds Investigationsmentioning

confidence: 99%

Section: Sem and Eds Investigationsmentioning

confidence: 99%

Section: And Table 2)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Reactive-field-assisted-sintering of freeze-dried powders in the BSCCO system

Badica

Aldica

Groza

et al. 2001

Supercond. Sci. Technol.

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“…The hysteresis in high T c superconductors has been given by using a bridge model in which edge pinning at the bank becomes a source of hysteresis since the surface currents in the narrow part of the bridge add to or subtract from the transport current depending on the direction of applied field [7]. Hysteretic behavior of transport critical current was reported by Abukay et al [8] for Bi (Pb)-Sr-Ca-Cu-O system and SEM studies on Bi (Pb)-Sr-Ca-Cu-O were reported by Bunescu et al [11].…”

Section: Introductionmentioning

confidence: 99%

Effect of pelletization pressure on structural properties and critical current hysteresis of ceramic superconducting Bi1.7Pb0.3Sr2Ca2Cu3Oy

Tepe

Avci

Abukay

2003

phys. stat. sol. (a)

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The effect of pelletization pressures on structural properties and critical current hysteresis of Bi 1.7 Pb 0.3 Sr 2 Ca 2 Cu 3 O y samples was investigated. The samples used in this study were prepared by classical solid-state reaction at the pressures from 100 up to 500 MPa. The obtained samples were characterized by resistance vs. temperature, (R-T), critical current density vs. applied magnetic field, (J c -H), material density vs. pressure, (ρ -P), XRD, SEM, and EDAX. The results of this study showed that the quality of electrical and structural properties of Bi-2223 bulk superconductors strongly depends on the pelletization pressure. Pressing of bulk samples at 400 MPa produces textured grain alignment and associates microstructural modifications in order to enhance flux pinning and thus increases current carrying capacities.

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