Role of dysprosium substitution on microscopy architecture, structural stability, and crack propagation mechanism in Bi-2212 engineering ceramics

Abstract This study achieves a strong link between microscopy architecture and fundamental characteristics including electrical conductivity, superconducting, and key mechanical design properties of Bi 2.1-x Dy x Sr 2.0 Ca 1.1 Cu 2.0 O y (Bi-2212) ceramic structures with different dysprosium molar ratio ranges of 0.00 ≤ x ≤ 0.10. The Dy/Bi substituted Bi-2212 ceramics are characterized by scanning electron microscopy (SEM), electrical resistivity ( ρ -T), Electron Dispersive x-ray (EDX) investigations, and microindentation Vickers hardness (H v ) tests. Powder x-ray diffraction (XRD) experimental inspection is also studied to support SEM and H v results. All experimental findings show significant improvement with an increase in the Dy impurity molar ratio to x = 0.01. On this basis, the Bi 2.09 Dy 0.01 Sr 2.0 Ca 1.1 Cu 2.0 O y ceramic structure exhibits the lowest resistivity of 8.95 mΩ.cm at 300 K and transition width of 4.75 K, and the highest <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>c</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>o</mml:mi> <mml:mi>n</mml:mi> <mml:mi>s</mml:mi> <mml:mi>e</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> of 85.00 K and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msubsup> <mml:mrow> <mml:mi>T</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>c</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>o</mml:mi> <mml:mi>f</mml:mi> <mml:mi>f</mml:mi> <mml:mi>s</mml:mi> <mml:mi>e</mml:mi> <mml:mi>t</mml:mi> </mml:mrow> </mml:msubsup> </mml:math> of 80.25 K. Additionally, XRD examinations show that optimum Dy ion substitution in the Bi-2212 system stabilizes the high superconducting phase by improving crystallinity, crystallite size, grain orientation distributions, texturing, and interlayer interactions. In contrast, excessive substitution severely deteriorates crystallographic properties. Further, SEM images reveal that the presence of optimum Dy impurity enhances the crystallinity, couplings between the adjacent layers, homogeneous surface appearance, and microstructure. Moreover, the key mechanical design features and stability of the durable tetragonal phase improve significantly for x = 0.01. As a result, the material exhibits superior mechanical properties, including a microhardness of 0.5556 GPa, fracture toughness of 0.5390 MPa.m 1/2 , elastic modulus of 45.5389 GPa, shear modulus of 18.2156 GPa, yield strength of 0.1852 GPa, and resilience of 0.3766 MPa under a 0.295 N load.