Synthesis of highly ordered hBN in presence of group I/IIA carbonates by solid state reaction

In this detailed study, the changes of microstructural, mechanical, and superconducting features of bulk Bi1.8Pb0.2Sr2.0Ca1.8Pb0.2Cu3Oy materials prepared at different milling time intervals (0.5 h ≤ x ≤ 8 h) were investigated in the most precise manner. The measurements of X-ray powder diffraction (XRD) and Vickers microhardness (Hv) were designed to scrutinize the bulk BSCCO samples. All the results of the measurements and calculations show that the characteristics responsible for the applications of the technology, industry, and engineering are significantly improved up to the 3 h milling time beyond that they tend to deteriorate. The enhancement of the characters is generally related to the transition from underdoped level of the (Bi, Pb)-2223 to the optimum level with the milling duration and this event approves that sufficient Pb nanoparticles penetrate the crystal structure. On the other hand, some of the reasons for the suppression in the superconducting properties are the presence of the porosity, disorder, defects, and the localization problem in the Cu-O2 consecutively stacked layers. In addition to those mentioned above, the other reasons are degradation in the crystallinity, reduction in the average crystallite size, and decrease in mobile hole concentration in the Cu-O2 layers. Similarly, the Pb inclusion rises the artificial random dislocations and grain boundary weak-links in the (Bi, Pb)-2223 superconducting system. Vickers microhardness measurements show that (Bi, Pb)-2223 bulk superconducting specimens exhibit typical indentation size behavior depending on the presence of both elastic and plastic deformations in the system. The results obtained from the hardness measurements have been analyzed by using Meyer law, PRS model, MPRS model, elastic–plastic deformation model, and Hays-Kendall approach. As a result, the Hays-Kendall approach was identified as the most successful model in describing the mechanical properties of the samples.

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“…The crystal sizes of the prepared samples were calculated using the Scherrer equation given below [9][10][11]…”

Section: Xrd Measurement Evidencesmentioning

confidence: 99%

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Sarıtekin

Uzumcu

2022

J Supercond Nov Magn

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“…This is in correspondence with the fact that the synthesized nanoscale hBN sample is well crystallized. Furthermore, in our previous studies (Öz, 2020; Öz, 2021; Öz et al, 2016) we emphasized obviously the importance of metal salt usage which provides regularity between the hBN layers and lowers seriously the formation temperature of the hBN structure. Moreover, the XRD pattern of the hBN sample without any additive (Figure 2e) indicates the turbostratic boron nitride formation.…”

Section: Resultsmentioning

confidence: 89%

“…On this basis, in the present study (O'Connor, 1962) method was chosen to synthesize the hBN structure due to its reliable, simple technique and relatively lower production temperature values. Previously on the literature (Öz, 2020; Öz, 2021; Öz et al, 2016), it was observed that the metal salts affect positively the formation of the hBN structure. Here, we thoroughly report the influence of some different borates; namely, the lithium tetraborate, sodium tetraborate, calcium metaborate, and ammonium pentaborate to find out the importance of metal usage (cation effect) on the formation of hBN structure.…”

Section: Introductionmentioning

confidence: 95%

“…Nanoscaled BN analogous to hBN morphology was synthesized by the reaction ammonium chloride with sodium azide (Shi et al, 2004); magnesium diboride (Shi et al, 2004); potassium tetrahydroborate (Zheng, Gu, Xu, & Liu, 2007); boric acid (Duan, Xue, Xu, & Sun, 2008); sodium borohydride (Bi et al, 2009); and boron trioxide (Lin et al, 2016). In addition, it is reported in the literature that nanostructured BN synthesis is successively achieved not only carbothermal reduction of boron carbide and boron trioxide but also reduction of boron trioxide by urea and ammonia gas in presence of fluxes (metal salts) (Gao & Li, 2003; Öz, 2020; Öz, 2021; Öz, Saritekın, Bozkurt, & Yildirim, 2016).…”

Section: Introductionmentioning

confidence: 99%

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Effect of borates on the synthesis of nanoscale hexagonal boron nitride by a solid‐state method

Öz

Bozkurt

Yılmaz

2021

Microscopy Res & Technique

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This study delves deeply into the effect of different borates (lithium tetraborate, sodium tetraborate, calcium metaborate, ammonium pentaborate) on the production and fundamental characteristic features of nanoscale hexagonal boron nitride (hBN) structure with the assistant of standard characteristic measurement methods, namely, Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). The hBN samples are synthesized by reaction of powder urea, boron oxide, and different kinds of borates via the modified O'Connor method (performed at a relatively lower main heat treatment temperature of 1,100°C). All the results obtained show that the usage of borates affects positively the formation of nanoscale hBN structure. In more detail, the FTIR experiment results reveal that the presence of two strong c peaks appeared at ~1,380 and ~780 cm−1 in the spectra points out the conventional BN in‐plane and out‐of‐plane vibrations, respectively. The XRD patterns also confirm the production of high‐ordered hBN as the existence of the main peaks of the corresponding hexagonal system. As for the SEM examination, it is found that all the hBN materials exhibit totally different crystallinity quality and microstructural characteristics. The hBN compound prepared by the sodium tetraborate content shows the most uniform surface appearance with the smoothest/densest crystal structure, best grain orientations, and finest grain interactions. Hence, the material with strong stretching of interatomic bonds shows the highest material (fracture) strength. Moreover, the TEM images illustrate that all the products are composed of uniform multi‐walled nanotubes and nanorods with an average length of ~250 nm.

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“…In YBCO doping, the amount of oxygen should be controlled. Because the amount of oxygen affects the number of carriers in the CuO 2 plane and determines the T c value [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

The Successful Incorporation of Nd Into Ba Site of Y0.9Ho0.1Ba2-yNdyCu3O7-δ Bulk Superconductors

Sarıtekin

Uzumcu

2022

J. Mod. Mech. Eng. Technol.

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This inclusive study reports the effect of the Nd atoms on the mechanical, microstructural, electrical and superconducting characteristics of Y0.9Ho0.1Ba2-yNdyCu3O7-δ superconductors with the aid of standard characterization methods, including X-ray diffraction, scanning electron microscopy, the bulk density, dc resistivity, and transport critical current density. The experimental results such as the degree of granularity, hole localization effect, room temperature resistivity, critical transition temperature, degree of the broadening, thermodynamic fluctuations, crystallinity, crystal plane alignments, crystal structure, grain size, phase purity and lattice parameters, the appearance of flux pinning centers, grain boundary weak-links, surface morphologies elemental compositions and distributions belonging to Y-site Ho and Ba-site Nd substituted Y-123 superconducting samples are discussed in detail for the first time. All the experimental findings show that the microstructural, electrical, mechanical and superconducting properties regularly improve with the increment in the HcN (Ho constant+Nd changeble) until a certain value of y=0.100, beyond which the characteristics tend to retrograde rapidly. This is attributed to the fact that excess penetration of the Nd damages the crucial properties given above.

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Synthesis of highly ordered hBN in presence of group I/IIA carbonates by solid state reaction

Cited by 9 publications

References 32 publications

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Improving Superconductivity, Microstructure, and Mechanical Properties by Substituting Different Ionic Pb Elements to Bi and Ca Elements in Bi-2223 Superconductors

Effect of borates on the synthesis of nanoscale hexagonal boron nitride by a solid‐state method

The Successful Incorporation of Nd Into Ba Site of Y0.9Ho0.1Ba2-yNdyCu3O7-δ Bulk Superconductors

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