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    Calculation of True Hardness Value of Zn added (BiPb)SrCaCuO Superconductor by Different Models
    (ELSEVIER SCI LTD, 2015) Toplu, Ahmet; Karaca, Ibrahim; Kolemen, Ugur
    Prepared by a wet method (BiPb)SrCaCuO superconductors micro-hardness properties was investigated by dynamic micro-indentation technique. The indentation load-displacement curves of the materials were plotted by applied load varying from 200 to 1800 mN. Micro-hardness numbers carry out from loading-unloading process showed load dependence hardness (LIE), i.e., indentation size effect (ISE). The ISE was examined with the theoretical models such as Meyer's law, the Hays-Kendal approach, the Elastic/Plastic Deformation model, the Proportional Specimen Resistance (PSR) model, and the Modified Proportional Specimen Resistance (MPSR) model. MPSR model was obtained the better model to calculate micro-hardness numbers of samples. According to this calculating result, the true hardness of superconductor were increasing with the increasing of the amount of Zn% and.Bi-2212 phase into mixture. (C) 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved.
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    Crystallographic effects of Boron doping into Sm-Ca-Cu-O Ceramic
    (Elsevier, 2021) Guler, Munir Taner; Karaca, Ibrahim; Unluer, Sahin
    In this work, we have especially focused on investigating the nano Boron doping effect into the SmCa-Cu-O Ceramic [1,2 ]. The samples produced suitable with nominal composition selected as Sm1.75Ca(2.20-x)BxCu3.4Oy (x = 0.0; 0.4, 0.8 and 1.0). This effect investigated through the TG/DTA, XRD, and SEM results. Lattice parameters (a, b , and c) got from the crystallographic knowledge, and they carefully calculated. The crystallographic growth seen because of the changing at the intensity of x-ray diffraction peaks. Increasing the Boron doping in the matrix have produced the crystal growth at especially SmBP and SmB10 samples, peaks intensity at 29 degrees (220) Miller indices, has increased from 1.602 to 10.883, respectively. Namely, with increasing B-doping resulted in a transformation of the phase. In this way (at Boron free sample) it has achieved the orthorhombic phase transformation to the tetragonal phase created in the matrix. (C) 2021 Elsevier B.V. All rights reserved.
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    Refinement of the Low-Temperature Phase with Nano SnO Doping in Ba-Ca-Cu-O Ceramics
    (Elsevier, 2021) Unluer, Sahin; Karaca, Ibrahim; Simsek, Nihat
    The SnO nano dopant effects on to the low-temperature phase have studied by the selected composition of Ba2Ca3Cu6-xSnxOy (x = 0.0; 0.5; 1.0; 1.5; 2.0). The samples produced by Melt-Growth Method (MGM). As well-known, the BaCaCuO superconductor has two phases; one of them occurs in the high superconducting transition temperature at 126 K, but this phase is unstable and requires high pressure. Because of these unfavorable conditions, Ba-Ca-Cu-O superconductors out of practically be an application to technology. The other is the low-temperature phase, in which superconducting transition temperature is nearly at 90-95 K. In this work, we focused on investigating the low transition temperature phase. The phase has a Tetragonal crystal structure with a P4 / mmm symmetry and lattice constants a = 6.517 angstrom and c = 8.410 angstrom. The effects investigated by the differential scanning calorimetry, energy dispersive X-ray, scanning electron microscope, and X-ray powder diffraction method results. Structural analysis has shown that the matrix has infiltrated by the use of the SnO as a dopant. Namely, the SnO doping has resulted as the low-temperature phase has a growing percentage of 73.875% within the volume fraction of the matrix. (C) 2020 Elsevier B.V. All rights reserved.