Effect of Ultra-sonicated Y2BaCuO5 on Top-Seeded Melt Growth YBa2Cu3Oy Bulk Superconductor (original) (raw)
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Fabrication and characterisation of large-grain YBa2Cu3O7 superconductors by seeded melt texturing
Physica C: Superconductivity, 1998
In this work, we investigate the fabrication and characterisation of YBCO single grain monoliths using a seeding melt growth technique. It was found that there exits a narrow temperature-composition window for the stable growth of single grain monoliths. Addition of platinum has the beneficial role of refining the Y211 particles size while remaining inert to Y123 matrix by forming a Pt-containing secondary phase. Pellets of diameter up to 3 cm were fabricated under isothermal slow cooling condition. Neutron scattering and field mapping show their single grain nature, in spite of the existence of low-angle grain boundaries and slightly misoriented grains. Small size samples exhibit high critical current densities, either from magnetic measurement or from direct transport measurement, while J are reduced three-to four-fold in large bulk c pellets. It is believed that main limitations for levitation forces in these pellets are oxygen inhomogeneities and cracks due to oxygen diffusion induced stresses. q 1998 Elsevier Science B.V. All rights reserved.
Coatings, 2021
The infiltration growth (IG) process is well-known as the most established technique consisting of Y2BaCuO5 (Y211) precursor powders and liquid phases toward the fabrication of bulk YBa2Cu3Oy (Y123) superconductor for high field industrial applications. We have reported the fabrication of Y123 bulks using this technique at various ratios of liquid phase source. In this study, the use of liquid phase source toward the infiltration growth of bulk Y123 superconductors at different ratios of Y123 and ErBa2Cu3Oy (Er123) mixed with Ba3Cu5O8 (Y035) was investigated to control the Y211 secondary phase content in bulk Y123 samples. The liquid phase content was optimized by varying the mass. The sample fabricated using Y123 liquid phase (Y1Er0) showed the onset of critical temperature Tc-onset = 91.85 K. Tc-onset slightly decreased with the addition of Er123. Microstructure analysis revealed a uniform distribution of Y211 secondary phase particles in the Y123 matrix. The Y1Er0 sample had the ...
ACS Omega, 2020
Growth and physical properties of bulk REBa 2 Cu 3 O 7−δ (REBCO) superconductors fabricated by the infiltration growth (IG) method strongly depend on the initial size and morphology of the RE 2 BaCuO 5 (211) particles. The present work details the novel method we developed for producing sharp-edged and surface-damaged 211 particles to be added to the REBCO bulks. We employed high-energy ultrasonic irradiation for pretreating the 211 particles and fabricated high-performance bulk single-grain YBa 2 Cu 3 O 7−δ (YBCO) superconductors via the top-seeded IG process. Increasing the ultrasound irradiation power and time duration mechanically damaged the surface of the 211 particles, producing more fine and sharp edges. Systematic investigations of the microstructural properties of the final YBCO bulks indicated that the size and content of the 211 particles gradually decreased without any additional chemical doping. The effective grain refinement and improved interfacial defect densities enhanced the critical current density by a factor of two at 77 K and self-field as compared to a YBCO sample fabricated without any pretreatment. A maximum trapped field of 0.48 T at 77 K was obtained for a sample (20 mm diameter) with 211 particles treated for 60 min and 300 W ultrasound radiation. The effectiveness of the novel method is demonstrated by the superior performance of the YBCO bulk samples prepared as compared to bulk samples fabricated with the addition of Pt and CeO 2. This method is novel, cost effective, and very convenient, maintaining high sample homogeneity, and is free of chemical contaminants as compared to other methods which significantly affect the properties of all REBCO bulk products grown by sintering, melt growth, and IG methods.
Journal of Superconductivity and Novel Magnetism, 2016
The fabrication of (RE)-Ba-Cu-O bulk superconductors, where RE is a rare-earth element such as Y, Gd and Sm, is both time consuming and expensive due to the complexity of the melt process and the slow growth rate of large, single grains. In this study, different approaches to the fabrication of bar-shaped, bulk YBCO superconductors are investigated and compared using single-and multipleseeding techniques via top-seeded melt growth (TSMG). Both the microstructural and superconducting properties of the bulk samples are investigated, including trapped field, critical current density, critical temperature and levitation force. The results of this study indicate that, in general, the superconducting properties of YBCO fabricated by a singleseeded process are significantly better than those of samples fabricated by a four-seeded process for non-bridge seeds. The differences between the samples are less pronounced in the levitation force measurements, however. In this paper, we attempt to explain the reasons for the similarities and differences observed between bulk samples fabricated by the different single-and multi-seeded processes.
1995
This study compared the microstructure, texturing, and functional properties (critical currents) of YBaâCuâO{sub 7-x}-based bulk pellets that were prepared by the quench-melt-growth-process (QMGP), melt-textured growth (MTG), and conventional solid-state reaction (SSR) approaches. Using two X-ray diffraction (XRD) methods, θ-2θ, and rocking curves, the authors found that the individual grains of two melt-processed pellets exhibited remarkable preferred orientational alignment (best rocking curve width = 3.2°). However, the direction of the preferred orientation among the grains was random. Among the three types of bulk materials studied, the QMGP sample was found to have the best J{sub c} values, â 4,500 A/cm² at 77 K in a field of 2 kG, as determined from SQUID magnetic data.
Microstructure of YBCO bulk superconductors with CeO 2 addition
Materials Science and Engineering B-advanced Functional Solid-state Materials, 2008
The refinement of Y2BaCuO5 (Y211) particles by CeO2 in the single-grain YBa2Cu3O7/Y2BaCuO5 (Y123/Y211) bulk superconductors of nominal composition Y1.5Ba2Cu3Ox prepared by top-seeded melt-growth process with Y2O3 addition has been studied by polarised light microscopy. It is shown that cerium is active in the Y211 particle refinement when it is solved in the peritectic melt, Lp. Observed growth of Y211 particles during sintering stage is ascribed to higher amount of melt induced by CeO2 reaction with Y123 phase producing barium cerate and CuO.
Materials Letters, 1991
The superconducting properties and the related microstructures of YBaCuO with BaTiOs addition, prepared by partial melt processing, were investigated with temperature-resistivity, magnetic hysteresis, X-ray diffraction and SEM EDX analysis. The YBaCuO samples with BaTiO, addition show a good superconducting property (r, above 90 K), in spite of the adding of 20 wt% of BaTiO,. The magnetization curve of a 5 wt% BaTiO, sample reveals that the adding renders a possible resistance to magnetic field. The added BaTiO, is decomposed and converted into another second phase, containing a large amount of Ba and Ti, during the peritectic reaction of liquid phase and 2-l-l phase. Almost none of the Ti is introduced into the l-2-3 matrix and the 2-i-l phase but into the second phase formed by the added element, retaining the good superconducting properties. I. In~odu~tion
Multi-seeded melt growth processed YBCO superconductors
Physica C: Superconductivity, 2001
Eects of processing variables on the top surface properties (the levitation force and trapped magnetic ®eld) of the multi-seeded melt growth process were studied. The variables were the number of seeds, seed distance, initial composition of a YBCO compact, variety of the grain junctions. The processing time was reduced by providing many growth sites for 123 grains. However, the properties were decreased as the number of seeds increased due to the poor connection of the grain junctions. We summarize the ways to minimize the degradation of the magnetic and levitation properties at the grain junctions.
Journal of superconductivity …, 2010
In this study, two kinds of melt-processed YBCO samples with Y 2 O 3 addition were fabricated and their microstructures were defined by XRD analysis and polarized light optical microscopy. The mechanical properties of these compounds have been investigated by measuring the Vickers hardness. The superconducting transition temperature was determined by inductive measurements for oxygenated and non-oxygenated samples. The compacted powders were located on a crucible with a buffer layer of Y 2 O 3 and a crucible with Y 2 O 3 powder freely poured to avoid liquid to spread on the furnace plate. It was found that the sample located on crucible with freely poured Y 2 O 3 powder has shown almost single crystal and indicated a very sharp transition curve.