Effect of Processing Parameters on the Morphology, Particulate, and Superconducting Properties of Electrospun YBCO Nanostructures

Superconductivity in nanostructured ceramics offers significant advantages over the conventional coarse-grained materials in view of miniaturization of superconducting electronic devices. In this paper, we report the formation of four morphologies of superconducting YBa2Cu3O7-δ (YBCO) nanostructures by electrospinning technique using polymeric polyvinyl pyrrolidone (PVP) solutions of different molecular weight and altering the total content of the metallic precursors. The morphologies prepared using this strategy are nanorods (NRs), nanogarlands (NGs), nanohierarchical (NH), and nanoparticles (NPs). Alternating current susceptibility measurements showed high critical temperatures (TC ~90 K) for the NH YBCO synthesized using PVP of the lowest molecular weight; whereas the YBCO NRs synthesized using a higher molecular weight polymer showed the lowest TC (82 K). A relationship between the particulate properties and TC was also observed – the lower is the pore size the higher is the TC. The YBCO NGs showed the highest specific surface area (7.06 m2/g) with intermediate TC (88 K). Electrospinning process appears an effective and controllable technique to produce different nanomorphologies with intrinsic properties suitable for practical applications.

Phase Transformations and Photocatalytic Activity of Nanostructured Y2O3/TiO2-Y2TiO5 Ceramic Such as Doped with Carbon Nanotubes

This work is devoted to the study of phase transition processes in nanostructured ceramics of the Y2O3/TiO2-Y2TiO5 type doped with carbon nanotubes as a result of thermal annealing, as well as to the assessment of the prospects of the effect of phase composition on photocatalytic activity. By the method of X-ray phase analysis, it was found that an increase in the annealing temperature leads to the formation of the orthorhombic phase Y2TiO5, as well as structural ordering. Based on the obtained UV spectra, the band gap was calculated, which varies from 2.9 eV (initial sample) to 2.1 eV (annealed at a temperature of 1000 °C). During photocatalytic tests, it was established that the synthesized nanostructured ceramics Y2O3/TiO2-Y2TiO5 doped CNTs show a fairly good photocatalytic activity in the range of 60–90% decomposition of methyl orange.

Nanostructured Zirconia-Based Ceramics and Composites in Dentistry: A State-of-the-Art Review

The objective of this paper is to review the current knowledge on the development of nanostructured zirconia-based ceramics and composites suitable for application in dentistry. Isi Web of Science, Science Direct, Scientific.net databases, and Google were searched electronically for the period of 1980 to the present, matching the keywords “nano” with the keywords: “Zirconia, ZrO2, Y-TZP, and dental, dentistry”. A total of 74 papers were found, with the majority coming from Asia, indicating a more active scientific interest on the topic in this geographic area, followed by Europe, South America, and North America. The research shows, even though the scientific activity on nanostructured ceramics was intense in the last fifteen years, the development of fully dense zirconia-based nanoceramics is yet at an initial stage, most of all from the point of view of the clinical applications. It has been demonstrated that nanostructured ceramics can show improved properties because of the reduction of the grain size to the nanoscale. This is also true for zirconia-based nanoceramics, where some improvements in mechanical, optical, as well as resistance in low-temperature degradation have been observed. Potential applications of this class of material in the dental field are discussed, summarizing the results of the latest scientific research.