Effect of Ag on the primary phase field of the high-Tc (Bi,Pb)-2223 superconductor

2000 ◽  
Vol 15 (2) ◽  
pp. 296-305 ◽  
Author(s):  
W. Wong-Ng ◽  
L. P. Cook ◽  
W. Greenwood ◽  
A. Kearsley
Keyword(s):  
Phase Field ◽  
Volume Fraction ◽  
Primary Crystallization ◽  
Primary Phase ◽  
Crystallization Field ◽  
Primary Phase Field ◽  
Liquidus Data ◽  
Primary Crystallization Field ◽  
High Tc ◽  
Melt Composition

The subsolidus equilibria and the primary phase field (crystallization field) of the 110 K high-Tc (Bi,Pb)-2223 ([Bi,Pb]:Sr:Ca:Cu) phase have been determined in the presence of Ag under a 92.5% Ar/7.5% O2 atmosphere (volume fraction). A total of 29 six-phase volumes that include both the (Bi,Pb)-2223 and Ag phases was observed. These subsolidus volumes are similar to those observed without the presence of Ag. The compositional range of initial melts of these volumes (mole fraction basis) covers BiO1.5 from 5.6% to 25.3%, PbO from 0.4% to 13.8%, SrO from 8.4% to 31.9%, CaO from 12.2% to 33.3%, CuO from 21.7% to 40.9%, and AgO0.5 from 1.2% to 6.3%. Based on these data, the primary crystallization field for the (Bi,Pb)-2223 phase in the presence of Ag was constructed using the convex hull technique. A section through this “volume” was portrayed by holding the AgO0.5, SrO, and CaO components at the median value of the 29 compositions while allowing projection on the other three axes (BiO1.5, PbO, and CuO). The net effect of Ag on the melt composition is a reduction in the PbO concentration and an increase in the SrO content. Applications of the liquidus data are also discussed.

Viscosity of Spinel Primary Phase Field Slags from Australian Brown Coals

2020 ◽  
Vol 34 (3) ◽  
pp. 3041-3056 ◽  
Author(s):  
Alexander Ilyushechkin ◽  
Alex Kondratiev ◽  
Chong He ◽  
Jin Bai ◽  
Xiaodong Chen ◽  
...  
Keyword(s):  
Phase Field ◽  
Primary Phase ◽  
Primary Phase Field ◽  
Brown Coals

Subsolidus phase equilibria of coexisting high-Tc Pb-2223 and 2212 superconductors in the (Bi, Pb)–Sr–Ca–Cu–O system under 7.5% O2

1997 ◽  
Vol 12 (11) ◽  
pp. 2855-2865 ◽  
Author(s):  
W. Wong-Ng ◽  
L. P. Cook ◽  
F. Jiang ◽  
W. Greenwood ◽  
U. Balachandran ◽  
...  
Keyword(s):  
Solid State ◽  
Solid Solutions ◽  
Ambient Pressure ◽  
Primary Phase ◽  
Primary Phase Field ◽  
Subsolidus Phase ◽  
High Tc ◽  
Bscco System ◽  
Compositional Space ◽  
Phase Relationships

The subsolidus phase relationships of the high-Tc 2223 superconductor in the (Bi, Pb)–Sr–Ca–Cu–O (BSCCO) system have been examined at 810–820 °C. All experiments were carried out at ambient pressure in a 7.5% O2 (92.5% Ar) atmosphere. Eleven phases were found to exist in equilibrium with the 2223 phase. These 11 phases include CuO and 10 oxide solid solutions. From among these phases, a total of 48 five-phase combinations including the 2223 and 2212 phases were investigated experimentally, and 16 equilibrium assemblages were found which define a multicomponent compositional space corresponding to the 2223 + 2212 solid-state compatibility region. The subsolidus data form a partial basis for future investigation of the Pb-2223 primary phase field.

The primary crystallization field and growth of Bi-2212 crystals in platinum and gold crucibles

2001 ◽  
Vol 231 (1-2) ◽  
pp. 194-202 ◽  
Author(s):  
A.B. Kulakov ◽  
I.G. Naumenko ◽  
S.A. Zver’kov ◽  
A.V. Kosenko ◽  
S.S. Khasanov ◽  
...  
Keyword(s):  
Primary Crystallization ◽  
Crystallization Field ◽  
Primary Crystallization Field

Phase Relations of the Bi-2201–CuO Pseudobinary Join as a Function of Oxygen Pressure

2000 ◽  
Vol 659 ◽  
Author(s):  
James K. Meen ◽  
Karoline Müller ◽  
Celia Salmeron ◽  
Don Elthon
Keyword(s):  
Phase Field ◽  
Ternary Phase ◽  
Invariant Point ◽  
Freezing Point ◽  
Ternary Eutectic ◽  
Primary Phase ◽  
Phase Relations ◽  
Primary Phase Field ◽  
Freezing Point Depression ◽  
Narrow Temperature Range

ABSTRACTPhase relations on the join Bi-2201–CuO have been determined as a function of P(O2). Most of the major changes that occur between P(O2) of 1 and 0.01 atm occur in the most oxidizing part of the range. Stoichiometric Bi-2201 occurs only at the most oxidizing conditions and in a narrow temperature range near the solidus. In the Bi-2201–CuO system, the ternary phase that forms has higher Bi:Sr and Cu:Sr than Bi-2201. That phase, Sr14Cu24Oy, and CuO occur in the subsolidus and the invariant point at which they coexist with liquid is a ternary eutectic. The liquid is more Sr-rich than the Bi-2201–CuO join. Decrease in P(O2) produces a change in the Bi- 2201 solid solution so that stoichiometric Bi-2201 does not occur. At P(O2) ≤0.5 atm, all Bi- 2201 solid solutions have Bi:Cu<2 but Bi:Sr near unity and Sr14Cu24Oy does not form. Small amounts of a phase believed to be Bi9Sr11Cu5Ox form under these conditions and the primary phase field of that phase crosses the pseudobinary join and minimum melting is at a ternary tributary reaction point. The liquid there is more Bi-rich than the join. Further decrease in P(O2) causes a continued freezing point depression and enlargement of the CuO primary phase field so that the compositions of multiply-saturated liquids move away from the CuO apex.

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