Effect of hard magnetic ferrite (Ba0.5Sr0.5Fe12O19) nanoparticles on the mechanical properties of the (Bi, Pb)-2223 phase
M. S. Hassan, Ibrahim Mohamed, M. Matar, A. I. Abou‐Aly, R. Awad, M. Anas
Abstract
Abstract To manifest the effect of hard magnetic Ba 0.5 Sr 0.5 Fe 12 O 19 nanoparticles on the mechanical performance of the (Bi,Pb)-2223 superconducting phase, nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) x /Bi 1.8 Pb 0.4 Sr 2 Ca 2 Cu 3.2 O 10+δ , with x = 0.00, 0.01, 0.02, 0.03, 0.04, 0.05, 0.10, and 0.20 wt%, were synthesized using a conventional solid-state reaction method. The X-ray diffraction (XRD) data revealed that adding nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) to the host (Bi,Pb)-2223 phase preserved the orthorhombic structure. The porosity ( P %) calculations revealed a decrease until x = 0.04 wt%, which suggests that the addition of nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) x reduces the number of voids and improves inter-grain connections, as confirmed by SEM micrographs. The superconducting transition temperature ( T c ) increased to 112 K with the inclusion of nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) up to x = 0.04 wt%. Vickers microhardness ( H V ) measurements were conducted at various applied loads (0.245–9.800 N) and a duration time of 45 s. The H V number increased with the addition of x up to x = 0.04 wt% but then decreased with further addition. Various models were employed for analysis and modelling of Vickers hardness ( H V ) versus test load (F), including Meyer’s law, Hays–Kendall (H–K) model, the elastic/plastic deformation (EPD) model, the proportional sample resistance (PSR) model, the modified proportional sample resistance (MPSR), and indentation-induced cracking (IIC) model. It was found that the PSR model was the most appropriate theoretical model for describing the microhardness of nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) x /(Bi,Pb)-2223 composites. Moreover, the elastic modulus ( E ), yield strength ( Y ), fracture toughness ( K ), brittleness index ( B ), and elastic stiffness coefficient ( C 11) were estimated as a function of the inclusion of nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) x . Furthermore, the indentation creep test (time-dependent Vickers microhardness) revealed that the dislocation creep mechanism exists in composite samples with low concentrations ( x < 0.05 wt%), whereas the dislocation climbs creep mechanism was observed for x ≥ 0.05 wt%.