Phase composition and properties of superconducting ceramics based on Bi1.7Pb0.3Sr2Ca2Cu3O y precursors fabricated by melt quenching in a solar furnace

In this study, the potential possibilities of the precision of the vibrating reed method for the evaluation of the Тс of superconducting precursors in an HTSC Bi-Pb-Sr-Cu-O system were investigated. A special technology for obtaining these samples by using solar energy for melting and following superfast melt quenching was applied to increase their internal inhomogeneity, allowing to receive high-quality textural ceramic samples of Bi1,7Pb0,3Sr2Can-1CunOy (n=2-30) showing critical temperatures of superconducting precursor transitions above bulk Тс. To determine critical temperatures of superconducting precursors above bulk Тс for the first time, the original vibrating reed method of studying these multiphase samples in an applied magnetic field was used. It was shown that this method has sensitivity to superconducting diamagnetism making possible to reveal new superconducting precursor phases above bulk Tc.

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LOW-RESISTANCE Bi/Pb CERAMICS CONTAINING Ts = 295К-315K PHASES SYNTHESIZED IN A SOLAR FURNACE (PARKENT)

CHEMISTRY AND CHEMICAL ENGINEERING ◽

10.51348/ulje2155 ◽

2020 ◽

Vol 2020 (3) ◽

pp. 20-24

Keyword(s):

Solar Energy ◽

Peritectic Reaction ◽

Heterogeneous System ◽

Mutual Influence ◽

Solar Furnace ◽

Low Resistance ◽

Superconducting Phases ◽

Superconducting Ceramics ◽

Methods Of Synthesis ◽

Layered Ceramics

The aim of this work is to obtain bulk textured superconducting ceramics based on glass-crystalline precursors of the Bi1.7Pb0.3Sr2Ca(n-1)CunOy (n=5-9) series. Technologies for obtaining superconducting materials are presented. The advantages of melt methods and “Super Fast Aloys Quenching–T” technology is shown. Compositions, methods of synthesis and study of properties of precursors and ceramics obtained by solar energy are presented. The interrelation of the morphology of glass-crystalline precursors and superconducting ceramics based on them is revealed. It is shown that nano-sized nuclei are the basis on which superconducting phases with Ts = 295-315K are formed as a result of the peritectic reaction. The mechanism of conduction in nanostructured layered ceramics containing higher superconducting phases is proposed. The contribution to the conductivity of low-resistance ceramics is assumed due to the mutual influence of Bi / Pb homologous phases, which represent a “quasi” heterogeneous system by analogy with the mechanism proposed by Rashba for heterophase semiconductors.

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Structure and Properties of Highly Porous Alumina-Based Ceramic Materials after Heating by Concentrated Solar Radiation

Ceramics ◽

10.3390/ceramics5010003 ◽

2021 ◽

Vol 5 (1) ◽

pp. 24-33

Author(s):

Vladimir G. Babashov ◽

Sultan Kh. Suleimanov ◽

Mikhail I. Daskovskii ◽

Evgeny A. Shein ◽

Yurii V. Stolyankov

Keyword(s):

Compressive Strength ◽

Phase Composition ◽

Solar Radiation ◽

Ceramic Materials ◽

Solar Furnace ◽

Prolonged Treatment ◽

Fibrous Materials ◽

Concentrated Solar Radiation ◽

Fusion Mode ◽

Heating Up

Three ceramic fibrous materials of the Al2O3-SiO2 system with different densities have been treated using concentrated solar radiation. The experiment was performed using technological capabilities of the Big Solar Furnace in the 2 modes: the first mode includes heating up to 1400–1600 °C, holding for 1.5–2 h; the second mode (the fusion mode) includes heating up to 1750–1900 °C until the sample destruction, which is accompanied by fusion. Upon completion of the experiment, the phase composition, microstructure, and compressive strength of the materials were studied. It was shown that the investigated materials retained their fibrous structure under prolonged treatment in the first mode up to temperatures of 1600 °C. The phase composition of the ceramic materials changes during the experiment, and with a decrease in the density, the modification is more pronounced. Treatment of all three materials under study in the fusion mode resulted in the formation of the eutectic component in the form of spherulites. The compressive strength of the materials was found to be slightly reduced after exposure to concentrated solar radiation.

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