Effect of Nano-Sized Eu Substituting on Mechanical Properties of Bi1.7Pb0.3Sr2Ca2Cu2.75Na0.25Oy Ceramic Superconductor System

In this paper, the morphological, structure and mechanical properties of the superconducting system Bi1.7Pb0.3Sr2-x(Eu)xCa2Cu2.75Na0.25Oy (x = 0.00, 0.20, 0.25 and 0.30) have been investigated. Phase formation, morphological structure and mechanical properties of nano-sized Eu (80 nm) substituted ceramic samples prepared by solid state reaction method were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and Vickers microhardness instrument, respectively. Bi, Pb-2223 high temperature phases, Bi-2212 low temperature superconductor phase, and minor impurity phase production were identified in the X-ray measurement data. In all samples, the main phase structure is the tetragonal symmetric Bi-2223 superconducting phase. According to the SEM examination findings, the Bi-2223 phase has been detected by flaky plate-like grain types. With a uniform distribution of grains and strong connections between them, the sample containing Eu at the nano-sized ratio of x = 0.25 has a less porous morphological structure. Because strong intergranular bonds and a decreased void structure were formed, the sample with nano-sized Eu substitution at x = 0.25 exhibited the best mechanical properties, according to the results of the microhardness measurement.