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A. L. Pessoa

Publications and source records attributed to A. L. Pessoa.

2 recordsLinked to original sources

Successful production of Solution Blow Spun YBCO+Ag complex ceramics

YBCO fabrics composed of nanowires, produced by solution blow spinning (SBS) are so brittle that the Lorentz force produced by induced currents can be strong enough to damage them. On the other hand, it is known that silver addition improves the mechanical and flux pinning properties of ceramic superconductors. Thus, in this work, we show how we successfully obtained a polymeric precursor solution containing YBCO$+$Ag salts, which can be spun by the SBS route to produce ceramic samples. Yttrium, barium, copper, and silver metal acetates, and polyvinylpyrrolidone (PVP) (in a ratio of 5:1wt [PVP:acetates]) were dissolved in a solution with 61.5 wt\% of methanol, 12 wt\% of propionic acid, and 26.5 wt\% of ammonium hydroxide, together with 6 wt\% of PVP in solution. Three different amounts of silver (10 wt\%, 20 wt\%, and 30 wt\%) were used in YBa$_2$Cu$_3$O$_{7-x}$. The TGA characterizations revealed a lowering of crystallization and partial melting temperatures by about \SI{30}{\celsius}. SEM images show that after burning out the polymer, a fabric composed of nanowires of diameters up to \SI{380}{\nano \metre} is produced. However, after the sintering process at \SI{925}{\celsius} for \SI{1}{\hour}, the nanowires shrink into a porous-like sample.

physics.app-ph

Solution Blow Spinning Control of Morphology and Production Rate of Complex Superconducting YBa2Cu3O7-x Nanowires

The demand for nanostructured materials can increase exponentially due to the miniaturization of devices and their potential application in different areas, such as electronic and medicine. Therefore, high production rates are essential for making nanomaterials commercially available. When electrospinning (ES) and solution blow spinning (SBS) are employed for producing ceramic nanostructures, the solution injection rate can influence the morphology without, however, supply the real ceramic production rate. In this work, complex superconducting YBa2Cu3O7-x wires were prepared by using the SBS technique. We also show that the morphology can be controlled by varying the injection rate of the polymer solution and the production rate is 4.7 to 33 times higher than the rates of equivalent ceramics produced by ES. Additionally, we also suggest the term Ceramic Production Rate to refer to the production rate of ceramic structures.

physics.app-ph