Mechanical and superconducting properties of BiPbSrCaCuO-PE and BiPbSrCaCuO-MgO composites

Abstract

In this work it is shown that the inherently weak mechanical properties of monolithic high-temperature superconductors can be improved by processing the superconductor into a composite. Both polyethylene (PE) and MgO were used to prepare a composite material with BiPbSrCaCuO (BSCCO) superconductors. Three-point bending tests were conducted on monolithic BSCCO, 50 vol% BSCCO-PE and 50 vol% BSCCO-MgO particulate composites. As expected, the PE composites exhibited an increased ductility in comparison with the monolithic material and a decreased flexural modulus, while the flexural strength remains comparable with that of monolithic BSCCO. Although the presence of a resistive percolation path could be demonstrated at and below room temperature, zero resistivity at was not observed and the magnetic expulsion force diminished after processing. Magnetic measurements show that this is due to poor intergrain coupling. In contrast to the PE composites, the BSCCO-MgO composites can be re-sintered after mixing. This provides an opportunity for the material to regain the intergrain couplings and results in the recovery of zero resistivity at 110 K and in magnetic expulsion due to intergrain currents. Mechanical measurement on the MgO composites showed a decrease in ductility, an increased flexural modulus and a comparable flexural strength.

Structural and mechanical properties of YBCO‐polystyrene composites

“…Generally, the elastic modulus increases with augmenting filler volume fraction, while all other tensile properties such as the ultimate stress and strain at break decreases with increasing filler volume fraction. 36 As expected, the elastic modulus is enhanced and the tensile stress decreased with increasing filler concentration in the case of YBCO/PS composites. The modulus enhancement is normally expected in particulate composites.…”

Yttrium barium copper oxide‐filled polystyrene as a dielectric material

“…fraction because the particles are completely separated from each other by the polymer. Frequency affects the value of the capacitive reactance and so also affects the circuit impedance, line current, and phase angle, since they are determined to some extent by the value of “ X c .” The higher the frequency of a parallel RC circuit, the lower is the value of “ X c .” This means that for a given value of R , the impedance is also lower, making the line current larger and more capacitive 22, 23…”

Mechanical properties of ceramic-polymer nanocomposites

“…For the case of perfect adhesion, under the assumption that the polymer breaks at the same elongation in the filled system as in the neat polymer. By Equation (15) it is believed that in the case of poor adhesion, the elongation is expected to decrease more gradually with filler loading.…”

“…These fillers, present in varying degrees, also affect the basic mechanical properties of the polymer [8][9][10][11][12]. In the present work we have synthesized a new class of ferroelectric ceramic material barium sodium niobate [13][14][15] and prepared composites out of it by mixing it with polystyrene. In this paper, we report a study on the mechanical properties of polystyrene/barium sodium niobate composites.…”