Abstract
A highly homogeneous composite precursor containing nano-scale particles was synthesized from the highenergy attrition milling of a mixture of metallic Y, metallic Cu and barium nitrate (Ba(N03)2) containing 5 wt.% silver. The particle size of the 20 hour attrition-milled precursor was in the range of 30~80 nm as estimated by the XRD technique and direct TEM observation. With the heat treatment of the attrition-milled precursor, an intermediate precursor with the overall composition Y:Ba:Cu:O=l:2:3:y, y>7 was synthesized. The analyzed Y:Ba:Cu:Ag:O molar ratio of the intermediate precursor by AES/AAS and iodimetric titration was 1:1.972:3.022:0.323:7.41, which was very close to the estimated composition: 0.5Y2O3+2BaCuO2.5+CuO +0.325Ag. Y123-Ag superconductors in powder or bulk forms were prepared using heat treatment or thermomechanical processing of the intermediate precursor containing BaCu02.5. The high oxygen orthorhombic Y123-Ag phase (y>7) was obtained in quenched samples which were held for 30 min or less at 950°C in ambient air. As the holding time extended to 40 min, the sample was still orthorhombic Y123-Ag (6.7<y <7). The transport critical current density (Jc) at 77 K and zero magnetic field for the quenched sample which was held for 40 min at 950°C was ~1.3xl03 A/cm2.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
