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Sintering kinetics of the superconducting YBa₂Cu₃O compound

01 Jan 1989-
About: The article was published on 1989-01-01 and is currently open access. It has received 1 citations till now.
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DOI
01 Jan 1991
TL;DR: In this article, the solubility of silver in the YBa2Cu3Ox compound has been studied and determined by a rigorous X-ray diffraction method and by using a USGS computer program which uses an iterative least square solution to calculate the lattice parameters and the standard deviations.
Abstract: The solubility of silver in the YBa2Cu3Ox compound has been studied. Ceramic YBa2Cu3Ox pellets with added silver ranging from 0 to 10 wt% were prepared and characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), wavelength dispersive X-ray spectroscopy (WDX), and secondary ion mass spectrometry (SIMS). The lattice parameters were precisely determined by a rigorous X-ray diffraction method and by using a USGS computer program which uses an iterative least square solution to calculate the lattice parameters and the standard deviations. The final precisions are ±0m005A for lattice parameters a and b, and ±o.oca A for the lattice parameter c. Silver appears to be present within the YBa2Cu3Ox grains. More intragranular silver was found inside quenched samples than slowly cooled samples. In both cases the silver solubility increased with the nominal silver concentration, which reached a constant level as the nominal silver concentration exceeded 2.5 wt%. The maximum silver solubilities are 0.41 and 0.37 wt% for samples quenched from 950°C and slowly cooled to room temperature, respectively. The intragranular silver concentrations were found to be much lower than the nominal silver concentrations added to the system. Along with the increasing intragranular silver concentrations, lattice parameters a and c, and unit cell volume of the orthorhombic YBa2Cu3Ox phase increased and appeared to reach constant values at higher silver concentrations. Lattice constant b remains relatively unchanged for all silver concentrations. Structural chemistry analyses suggest that the dissolved silver ions may substitute copper ions at Cu(1) sites of the YBa2Cu3Ox unit cell. The maximum atomic fraction of Cu substituted by Ag is about 0.023 at room temperature, i.e. y-0.023 for YBa2Cu3_yAgy0x. The maximum value of y is about 0.025 for samples quenched from 950°C. 11

1 citations


Cites background from "Sintering kinetics of the supercond..."

  • ...First, the occupancy of oxygen in the orthorhombic phase at 0(5) sites on the a axis is very low, only about 0....

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References
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DOI
01 Jan 1991
TL;DR: In this article, the solubility of silver in the YBa2Cu3Ox compound has been studied and determined by a rigorous X-ray diffraction method and by using a USGS computer program which uses an iterative least square solution to calculate the lattice parameters and the standard deviations.
Abstract: The solubility of silver in the YBa2Cu3Ox compound has been studied. Ceramic YBa2Cu3Ox pellets with added silver ranging from 0 to 10 wt% were prepared and characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), wavelength dispersive X-ray spectroscopy (WDX), and secondary ion mass spectrometry (SIMS). The lattice parameters were precisely determined by a rigorous X-ray diffraction method and by using a USGS computer program which uses an iterative least square solution to calculate the lattice parameters and the standard deviations. The final precisions are ±0m005A for lattice parameters a and b, and ±o.oca A for the lattice parameter c. Silver appears to be present within the YBa2Cu3Ox grains. More intragranular silver was found inside quenched samples than slowly cooled samples. In both cases the silver solubility increased with the nominal silver concentration, which reached a constant level as the nominal silver concentration exceeded 2.5 wt%. The maximum silver solubilities are 0.41 and 0.37 wt% for samples quenched from 950°C and slowly cooled to room temperature, respectively. The intragranular silver concentrations were found to be much lower than the nominal silver concentrations added to the system. Along with the increasing intragranular silver concentrations, lattice parameters a and c, and unit cell volume of the orthorhombic YBa2Cu3Ox phase increased and appeared to reach constant values at higher silver concentrations. Lattice constant b remains relatively unchanged for all silver concentrations. Structural chemistry analyses suggest that the dissolved silver ions may substitute copper ions at Cu(1) sites of the YBa2Cu3Ox unit cell. The maximum atomic fraction of Cu substituted by Ag is about 0.023 at room temperature, i.e. y-0.023 for YBa2Cu3_yAgy0x. The maximum value of y is about 0.025 for samples quenched from 950°C. 11

1 citations