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The influences of (isothermal hot pressing-doping) treatment on the microstructure, electrical and mechanical properties of Bi2Sr3-xCaxCu2O8+δ (BSCCO), x ranging from 0.0 to 2 are assessed. BSCCO pellets were prepared by isothermal hot pressing (IHP) technique. The experimental works in this study consists of dc electrical resistivity measurements...
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... All parameters follow the same trend, increasing systematically with increasing the nano-(Ba 0.5 Sr 0.5 Fe 12 O 19 ) concentration up to x = 0.04 wt%, and then decreasing to x = 0.20 wt%, as shown in Table 6. The toughness (K f ) of high-temperature superconductors is the most important parameter, because it affects the material's mechanical behavior, which is the material's capacity to withstand cracks [99]. The toughness increased at the optimum of 0.04 wt% by 6.529% of the pure sample due to an increase in the surface energy α 1 . ...
To manifest the effect of hard magnetic Ba0.5Sr0.5Fe12O19 nanoparticles on the mechanical performance of the (Bi,Pb)-2223 superconducting phase, nano-(Ba0.5Sr0.5Fe12O19)x/Bi1.8Pb0.4Sr2Ca2Cu3.2O10+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-(Ba0.5Sr0.5Fe12O19) 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-(Ba0.5Sr0.5Fe12O19)x reduces the number of voids and improves inter-grain connections, as confirmed by SEM micrographs. The superconducting transition temperature (Tc) increased to 112 K with the inclusion of nano-(Ba0.5Sr0.5Fe12O19) up to x = 0.04 wt%. Vickers microhardness (HV) measurements were conducted at various applied loads (0.245–9.800 N) and a duration time of 45 s. The HV 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 (HV) 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-(Ba0.5Sr0.5Fe12O19)x/(Bi,Pb)-2223 composites. Moreover, the elastic modulus (E), yield strength (Y), fracture toughness (K), brittleness index (B), and elastic stiffness coefficient (C11) were estimated as a function of the inclusion of nano-(Ba0.5Sr0.5Fe12O19)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%.
... The fact that the c cell parameter decreases is explained by the rise in the valence of Bi which results in an increase in the coulomb attraction in the BiO layer [88]. The oxygen content of the (Bi,Pb)-2223 superconductor has a major influence on the c/a ratio, particularly CuO bonding in CuO 2 planes and the excessive oxygen content inside the BiO layers [89,90]. Cu 2+ ions experience a Jahn-Teller distortion due to the high oxygen content, which lowers the Table 1 Variation of structural and refinement parameters of nano-(YIG) x /(Bi,Pb)-2223 composites. ...
... The lattice parameters a, b and c were determined by applying a Reitveld refinement on the XRD patterns using the MAUD software [23], as shown in the graphs of The values of c a −1 show a decrease with the addition of CdO nanoparticles. It is reported that the ratio c a −1 is strongly dependent on the oxygen content of the Bi-2212 superconducting phase [27][28][29]. In particular, the excessive oxygen content within the BiO layers and the Cu-O bonding in the Cu-O planes. ...
This investigation reports the effect of the addition of CdO nanoparticles on the (Bi,Pb)-2212 superconducting phase. The superconducting samples of general formula (CdO)x Bi1.6 Pb0.4 Sr1.9 Ca1.1Cu2.1 O8 (x = 0.00, 0.01, 0.02, 0.05, and 0.1 wt%) are synthesized using the conventional solid-state reaction technique. Powder X ray diffraction analysis confirms the formation of a single-phase orthorhombic Bi-2212. The variations in the lattice parameters are explained based on the Jahn Teller distortion induced by the increase in the oxygen content owing to the addition of the CdO nanoparticles. The increase in the oxygen content is confirmed via Idiometric titration analysis. The grain morphology is investigated using scanning electron microscopy (SEM). The effect of CdO addition in enhancing grains connectivity by the filing of pores and voids is revealed. Fourier transform infrared (FTIR) spectroscopy is conducted to analyze the functional groups, based on the effect of calcination temperature and CdO addition. Dc-electrical resistivity measurements and I-V characteristics show an enhancement of the superconducting transition temperature (Tc) and the critical current density (Jc) with CdO addition up to x=0.05 wt%, followed by a further decrease. By analyzing the results of the X-ray photoelectron spectroscopy (XPS), the variations of the superconducting properties are explained based on the preferred substitution of Pb2+ ions in the Bi3+ or Cu2+ sites induced by the variations in the oxygen content generated by the addition of CdO nanoparticles.
... Finally, PSR model is determined as the most successful model describing the mechanical properties of our samples. Similar behavior was observed by Khalil [83] studying the influence of isothermal hot pressing–doping treatment on the microstructure, electrical, and mechanical properties of Bi 2 Sr 3−x Ca x Cu 2 O 8+δ bulk samples. Also, to confirm PSR model is the best model, the deviation percentages between the experimental and theoretical true microhardness with x according to each model are calculated for (Bi 1.8 Pb 0.4 )Sr 2 Ca 2.1−x Ho x Cu 3.1 O 10+δphase and their values are listed in Table 7. ...
The effect of the partial substitution of Ca²⁺ by Ho³⁺ ions on the electrical and mechanical properties of the superconducting phase (Bi,Pb)-2223 was studied. Superconducting samples of the type (Bi1.8Pb0.4)Sr2Ca2.1−xHoxCu3.1O10+δ were prepared by solid-state reaction technique under ambient pressure, and characterized by means of X-ray powder diffraction (XRD) and scanning electron microscopy (SEM). The superconducting transition temperature Tc and pseudogap temperature T* were estimated from electrical resistivity measurements, while the critical current density Jc was determined from I–V curves. The electrical resistivity data were discussed according to bipolaron model in the absence of thermally excited individual polarons. The sample with x = 0.025 showed the highest phase volume fraction, Tc, and Jc. Room temperature Vickers microhardness measurements were carried out at different applied loads (0.25–5 N) in order to investigate the performance of the mechanical properties of (Bi1.8Pb0.4)Sr2Ca2.1−xHoxCu3.1O10+δ phase. It was found that all the samples exhibit normal indentation size effect (ISE). The Vickers microhardness number HV increased as x increased from 0 to 0.025. The experimental results were discussed in view of Meyer’s law, Hays–Kendall (HK) approach, elastic/plastic deformation (EPD) model, and proportional specimen resistance (PSR) model. The load independent (true) microhardness of (Bi1.8Pb0.4)Sr2Ca2.1−xHoxCu3.1O10+δ superconducting samples showed identical behavior to that of the PSR model.
BSCCO 2212 süperiletken sistem, ekleme ve kısmi değiştirme yöntemleri nedeniyle açık bir yapıya sahip olduğundan birçok çalışma yapılmış ve makaleler yayınlanmıştır. Bu çalışmada, BSCCO 2212 süperiletkeninde belirli bir oranda Bi-Ga kısmi yer değiştirmesi yapılarak Ga oranı artırılarak elde edilen örneklerin duyarlılığı ölçülerek Ga'nın yapının süperiletkenliğine etkisi araştırılmıştır. Her numunenin mekanik özelliklerini incelemek için Vickers mikro sertlik ölçümleri kullanıldı. Numunelerin yapısal özelliklerini belirlemek için x-ışını kırınımı (XRD) analiz sonuçları değerlendirildi ve taramalı elektron mikroskobu (SEM) görüntüleri ile kristal yapı oluşumları gözlemlendi.
The current investigation reports the influence of the addition of CdFeO nanoparticles on the structural and superconducting properties of the (Bi,Pb)-2212 phase. The formation of an orthorhombic phase of Bi-2212 superconductor is confirmed by the X-ray powder diffraction measurements. The scanning electron microscope measurements show an improvement in the grain connectivity and a decline of voids due to the CdFeO nanoparticles addition. The Fourier transform infra-red spectroscopy is used to associate the absorption bands to equivalent functional groups. The DC-electrical resistivity and the I-V characteristic measurements show an enhancement of the superconducting transition temperature (Tc) and the critical current density (Jc) up to 0.02 wt% addition of CdFeO, respectively. The elemental composition and oxidation states are determined using X-ray photoelectron emission spectroscopy. The results suggest a correlation between the electric behavior and the cationic equilibrium reactions among Pb²⁺ ions in Bi³⁺ or Cu²⁺ sites.
The effect of CdMnO addition on the physical properties of Bi-2212 superconductors was investigated. The conventional solid-state reaction technique was employed for the synthesis of (Cd0.95Mn0.05O)x Bi1.6 Pb0.4 Sr1.9 Ca1.1 Cu2.1 O8+δ samples with 0.00 ≤ x ≤ 0.10 wt.%. The X-ray diffraction confirms the formation of the orthorhombic phase of Bi-2212 superconductors. The lattice parameter a shows an increase with x, conversely the lattice parameters b and c show a decrease. The scanning electron microscope (SEM) images have shown an enhancement in the grain connectivity and a reduction of voids due to the CdMnO addition. The Fourier transform infrared (FTIR) spectroscopy analysis shows a remarkable shift in the wave number positions due to the addition of CdMnO nanoparticles. The superconducting transition temperature (Tc) and the critical current density (Jc) show an enhancement with CdMnO addition up to x = 0.05 wt.%. The elemental composition and oxidation state of all elements were determined from the X-ray photoelectron emission (XPS) analysis. The work suggests a correlation between the variations of the superconducting properties and the dynamics of the cationic equilibrium reactions among Pb²⁺ ions in Bi³⁺ or Cu²⁺ sites. These equilibrium reactions are induced by the variations in the oxygen content produced by the addition of CdMnO nanoparticles.
The influence of PbF2 doping on the electrical and mechanical properties of Bi1.8Pb0.4Sr2Ca2.1Cu3.2O10+δ superconducting phase was studied. (PbF2)x Bi1.8Pb0.4Sr2Ca2.1Cu3.2O10+δ samples were prepared by the solid-state reaction method. The PbF2 content 'x' was varied from 0.0 to 0.3 of the sample’s total mass. The characterization of the prepared samples was established by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and Proton Induced Gamma ray Emission (PIGE). Moreover, the electrical resistivity 'ρ(T)' and the transport current density 'J' measurements were carried out via four-probe technique. Phase examination by XRD indicated that the PbF2 doping enhanced the (Bi, Pb) –2223 phase formation up to x = 0.10. On the other hand, the high concentrations of PbF2 retarded the phase formation. Granular investigation, from scanning electron microscope, showed that the grain size was increased as x increased from 0.05 to 0.20 with more grain orientation and inter-coupling between superconducting grains. The results of electrical and mechanical measurements showed that the superconducting transition temperature (Tc), the transport critical current density (Jc) and the Vickers microhardness Hv were found to have optimal value at x = 0.1.
Micro-indentation tests provide useful information on mechanical properties such as strength, deformation characteristics and fracture toughness of the ceramic materials. Therefore, a micro-indentation study has been carried out to characterize the mechanical properties of Bi2Sr2Ca1Cu2O8+δ + x wt % Ag (x = 0.0, 0.05, 0.15, 0.25 and 0.50) samples fabricated by hot pressing technique. Vickers hardness, elastic modulus, elastic stiffness coefficient, brittleness index, yield strength, compressive strength, and fracture toughness values of the samples were determined by using apparent micro-hardness. Additionally, load independent values of elastic modulus, elastic stiffness coefficient, brittleness index, yield strength and fracture toughness were also improved by using true microhardness. The experimental results have been analyzed by the theoretical models being proposed in the literature (Meyer’s Law, the elastic/plastic deformation model, proportional sample resistance model, Hays–Kendall model). According to the obtained results, Hays–Kendall model was determined to be as the most suitable model in the plateau region for the all samples showing indentations size effect behavior. The results show that the values of microhardness, strength, elastic parameters and fracture toughness of the samples increased with an increase in the Ag addition. The results exhibit that, it is possible to control the mechanical properties of the Bi-2212 ceramic composites by increasing the Ag addition
Bis(cyclohexylammonium) terephthalate (BCT) and cyclohexylammonium 4-methoxy benzoate (C4MB) single crystals were successfully grown by the slow evaporation solution growth technique. The harvested crystals were subjected to single-crystal X-ray diffraction, spectral, optical, thermal and mechanical studies in order to evaluate physiochemical properties. The Kurtz and Perry technique for second harmonic generation (SHG) study revealed that the powdered materials of BCT and C4MB exhibit SHG efficiency 0.2 times less and 1.3 times greater than that of standard reference material potassium dihydrogen phosphate. C4MB crystal exhibits high efficiency than BCT, because of methoxy group substituted in the para position of phenyl ring. With high SHG efficiency and thermal stability para substituted C4MB crystal will be a potential candidate for optical device fabrication.
