Low-cost and high-performance 3D printed YBCO superconductors

High-performance YBCO 123 (YBa₂Cu₃O_7-x) bulk superconductor samples were produced using the 3D printing paste-extrusion technique. The YBCO powder obtained after sintering a pre-mixture of Y₂O₃, BaCO₃ and CuO powders at 950 °C was used in the formulation of pastes for extrusion in a 3D freeform printer. The 3D samples printed from pastes containing the pre-mixture powders were sintered, while those produced using the YBCO powder were not. X-ray diffraction (XRD), energy dispersive spectroscopy (EDS) and Raman analysis all confirmed the YBCO phase after sintering, both in the powder and in the samples made with the pre-mixture. Scanning electron microscopy (SEM) images revealed powder grains of heterogeneous size and geometry, as well as grain aggregation, in the sintered samples. Superconducting quantum interference device (SQUID) measurements taken within a fixed magnetic range revealed that the printed pieces have a typical magnetization temperature of 92 K, reaching ?1.43 emu/g and ?1.59 emu/g respectively a zero-field-cooled magnetization (ZFC) for sintered and non-sintered printed samples.     

A comparative study of (Ce) and (Gd) doping influence on the superconducting properties of YBCO ceramics

This work is devoted to investigate the structural and electrical properties of the Ce, Gd-doped YBCO superconductors bulk ceramics. YBa_2-xRE_xCu₃O_7−δ (x = 0, 0.01, 0.05, 0.1) (RE = Gd, Ce) samples were prepared by means of conventional solid-state reaction. X-ray diffraction analysis was carried out to identify the present phases in the as-prepared samples followed by the determination of their lattice parameters. Fourier Transform Infrared Spectroscopy (FTIR) was used to identify the functional groups. Furthermore, the morphology and the surface roughness of the studied samples were characterized using Scanning Electronic Microscopy (SEM) and Atomic Force Microscopy (AFM). Vickers Micro-hardness of the as-prepared samples was examined. Besides, the electrical resistivity measurements were achieved to determine the critical transition temperature T_C and the critical current density J_C.The effect of Ce and Gd additions is clearly noticed in the obtained results, where all the prepared samples are superconductors with the presence of Y123 as a major polycrystalline phase. From the XRD patterns, the intensities of the Y123 corresponding peaks decrease with further increasing the Ce and Gd contents. In addition, the variation of the cell parameters was significant after additions of both Ce and Gd, which affect the grain size and the oxygen content of the YBa_2-xRE_xCu₃O_7−δ system. An improvement of the structure and surface roughness is observed on SEM and AFM images. Likewise, Vickers micro-hardness has increased after the Ce and Gd additions. Although, the critical transition temperature T_C was not further increased upon Ce or Gd additions compared to the undoped YBCO samples. Nevertheless, an exception has been recorded with an increase of T_C for YBa_2-xRE_xCu₃O_7−δ with (RE = Gd, x=0.01) to reach 88 K. In contrary, an improvement of the deduced critical current density J_C was achieved for all Ce-doped YBCO samples unlike those of Gd-doped samples.     

Synthesis and properties of YBa2Cu3O7-δ – Y2Ba4CuWO10.8 superconducting composites

YBa₂Cu₃O_7-δ (YBCO) is a well-known high-temperature superconductor. However, its critical current density and thus maximum trapped magnetic field can be improved significantly by introducing the secondary phases (artificial pinning centers). In this contribution, we successfully prepared YBCO single-grain bulks with Y₂Ba₄CuWO_10.8 phase serving as a source of pinning centers. This phase was prepared by solid-state reaction and further refined by milling. In the next step single-grain YBCO bulks with homogeneously distributed Y₂Ba₄CuWO_10.8 were prepared by top-seeded melt growth. Precursors as well as the final product were characterized by XRD, SEM and EDS. The phase composition of YBCO bulks containing Y₂Ba₄CuWO_10.8 was analyzed using Rietveld analysis. Thermal stability of YBCO bulk was studied by STA. Furthermore, PPMS was used to study electrical resistivity and critical current density. Bulk superconducting properties such as levitation force and trapped field ability were also measured.     

New versatile synthesis for low dimension superparamagnetic YBa2Cu3O7−x nanoparticles

This paper describes the synthesis and characterization of YBa₂Cu₃O_7−x (YBCO) nanoparticles obtained through an environmentally friendly chemistry approach. Y-, Cu- acetates and Ba trifluoroacetate were used for the synthesis of the precursor gel. Moreover, sucrose and pectin reagents were added as chelating agents inducing the formation of small size oxide nanoparticles. The thermal decomposition process of the precursor powder was investigated by thermal analysis correlated with mass spectrometry. The chemical nature, structure and morphology of the particles were investigated by X-Ray diffraction (XRD), Transmission Electron Microscopy (TEM) and Fourier Transform Infrared Spectroscopy. According to XRD analysis the nanoparticles have an orthorhombic structure and the average diameter between 18–30 nm, additionally confirmed by TEM measurements. The superparamagnetic behavior at room temperature of the YBCO nanoparticles has been clearly evidenced by magnetization measurements. Furthermore, the effect of the annealing atmosphere on the magnetic properties has been studied.     

Metal Organic Deposition of Lanthanum Zirconate Buffer Layer on Biaxially Textured Ni-5%W Substrate

In this study,a simple template consisted of Y2O3 and La2Zr2O7 (LZO) layers was fabricated on rolling assisted biaxially textured Ni-5at%W substrates for YBa2Cu3O7-δ (YBCO) coated conductors.A thin sputtered Y2O3 layer (～20 nm) was introduced as a seed layer in order to induce epitaxial growth of metal organic deposited LZO layer.The effects of Y2O3 layer,annealing temperature and dwelling time on the phase and texture of the LZO films were systematically investigated.X-ray diffraction exhibited that the LZ...     

用于制备YBCO薄膜的光辅助MOCVD反应器内流动现象的数值研究

对一种制备YBCO薄膜的光辅助MOCVD反应器内的流动现象进行了三维数值模拟研究.在模拟计算中,分别改变基座与进口的相对角度(Φ)、反应器顶壁倾斜角度(Ψ),得出反应器中流场的相应变化.根据对模拟结果的分析,发现当基座平面与进气口轴线之间的夹角Φ=22.5°及反应器顶壁倾角ψ=30°时,基片表面气流速度大小合适,分布均...     

MOCVD法制备YBCO高温超导体所需前驱盐的制备研究

通过金属有机源化学气相沉积技术(MOCVD)已可制得Ic达280 A/cm,Ic×L为300330 A.m的高性能YBCO带材,表现出巨大的优势和诱人的应用前景。进一步提高前驱盐的挥发性和批次稳定性不但能降低YBCO带材的生产成本、也能提高其性能稳定性。本研究报道了MOCVD法制备YBCO所需β二酮中间体TMHD及其钇、钡、铜金属有机前驱盐的制备,通过红外光谱和核磁共振谱对其化学结构予以确认;同时以金属钡与TMHD在正戊烷或正己烷中制备了无水β-二酮钡盐(Ba[tmhd]2),随后用五乙烯六胺为辅助配体(L)制备了挥发性更好的无水复合配体钡盐(Ba[tmhd]2.L),并通过热重分析技术比较了各前驱盐的挥发性,结果表明:辅助配体五乙烯六胺对提高钡盐挥发性作用显著。     

双面高温超导带材研究进展

介绍了采用反应溅射法制备双面Y<,2>O<,3>双面种子层长带材,通过引入水汽使Y原子在RABiTS基带上氧化成膜,同时有效的避免了基带的氧化.通过对工艺参数的优化,成功制备了高质量的Y<,2>O<,3>种子层,其面内面外半高宽仅为3.8°和1.4°,大大改善了金属基带的双轴织构特性,同时薄膜表面粗糙度仅为2.8nm.在制备的高质量种子层上采用溅射方法外延生长YSZ阻挡层和CeO<,2>模板层,薄膜表面光滑,并具有良好的均匀性和双面一致性.用双倒简靶溅射法制备YBCO超导层,采用旋转结合轴向自动进退,改善了薄膜受热不均的现象,获得了高质量的双面高温超导带材.其中短样双面临界电流Ⅰ<,c>之和超过了400 A/cm-w,同时成功制备了长度超过1米,Ⅰ<,c>>210 A/cm-W的双面高温超导带材.     

涂层导体在北京有色金属研究总院的研究进展

YBCO涂层导体即第二代高温超导带材,是实用化超导材料研究领域的热点.介绍了北京有色金属研究总院多年来在涂层导体制备技术方面所从事的研究工作,包括立方织构金属基带、隔离层、YBCO涂层的研究以及自主研发了多台连续的动态真空镀膜装置,例如磁控溅射、电子束蒸发、脉冲激光等.列举了所承担的科技部"863"和‘973'计划课题,涉及涂层导体研究工作的内容和取得的阶段成果.最后,展示了目前拥有的实验设施,掌握的制备技术,达到的技术水平和获得的专利.     

Synthesis temperature of Ba4CuPt2O9 compounds and the influence of their addition on the orientation of the c-axes of fluorine-doped YBCO superconductors

An experimental study has been carried out to investigate the synergistic effect of Ba₄CuPt₂O₉ compounds on the critical current density of fluorine-doped YBCO superconductors. The Ba₄CuPt₂O₉ compounds were synthesized by a solid state reaction. It was found that the synthesis temperature of the Ba₄CuPt₂O₉ compounds was over 800°C, which was higher than that ever reported previously. In addition, the influence of Ba₄CuPt₂O₉ compounds on the critical current density of YBCO superconductors has been investigated using two types of Ba₄CuPt₂O₉ compounds: one is not heat-treated, i.e. source materials; and the other is heat-treated at 950°C. It was found that the former affected the orientation of the c-axes, but the latter did not have an influence on the orientation of the c-axes, but adversely affected the superconductivity of samples quenched at temperatures above 850°C.