PDF Publication Title:
Text from PDF Page: 009
whose phase transition of tetragonal to monoclinic was seen to occur at the calcination Energies 2022, 15, 6452 9 of 21 temperature of 800 °C, with an evident mixture of both phases. In another study [85], ZrO2 nanoparticles were produced by conventional and ultrasound-assisted precipitation in an alkaline medium followed by calcination at different temperatures ranging from 400 °C to 900 °C for 3 h. At 800 °C, a mixture of three ZrO2 phases was reported, i.e., tetragonal- monoclinic-cubic phases. The present study has the advantage of having monoclinic ZrO2 seen that the particles display a nearly spherical shape (Figure 4a), and from the EDS measurements,ahomogeneousdistributionofZr(Figure4b)andO(Fiigure4c)iiseviidentt.. No impurities were detected by EDS. as the dominant phase after a fast calcination treatment of 15 min instead of hours. 3.1.3. Electron Microscopy 3.1.3. Electron Microscopy Figure4sshhoowssththeeSESMEMimiamgaegseosfothfethZerOZrOna2nnoapnaorptiacrletisclseysntshyenstihzesdizuednduerndmeir- 2 mcroicwroawveavirerairdraiadtiaotniowniwthitahfaufruthrtehrecraclacilnciantaiotinontrteraetamtmenetnattat80800C°Cfoforr1155minin..Itcanbe Figure 4. (a) SEM image of the ZrO nanoparticles synthesized by microwave irradiation with a Figure 4. (a) SEM image of the ZrO2 nanoparticles synthesized by microwave irradiation with a ◦ further calcination step at 800 °C for 15 min, together with the correspondiing EDS maps of Zr (b) and O (c). and O (c). ◦ The atomic percentages (at.%) of Zr and O were also estimated from EDS spectra for the ZrO2 nanopowders before and after the calcination treatment (Table 1). The atomic percentage values were close to those expected for pure zirconium oxide (the Zr/O ratio percentage values were close to those expected for pure zirconium oxide (the Zr/O ratio was 1:2 for the material before calcination and 1:2.7 after calcination). was 1:2 for the material before calcination and 1:2.7 after calcination). Table 1. EDS point analysis of the ZrO2 nanopowders before and after the calcination treatment at 800 ◦C for 15 min. ZrO2 Nanopowder before the Calcination Treatment Elements Zr O at.% 33.3 66.7 ZrO2 Nanopowder after the Calcination Treatment Zr O 26.9 73.1 TEM measurements were also carried out for the ZrO2 nanoparticles produced under microwave irradiation before and after calcination (Figure 5). The TEM images of the ZrO2 nanoparticles before calcination demonstrate the presence of heterogeneous particles with an average particle size of 6.7 ± 1.9 nm. Abnormal large particles were also observed (Figure 5a,b). In terms of particle shape, microwave synthesis resulted in different nanos- tructures, including nanospheres, nanosquares and irregular-shaped nanoparticles. The heterogeneity detected is consistent with the XRD and Raman spectroscopy results, where it was shown that after microwave synthesis, there was a mixture of ZrO2 phases, with the presence of both tetragonal and monoclinic ZrO2 phases (Figures 2a and 3a). The lattice spacing of 0.3 nm measured in Figure 5c was consistent with the d-spacing of the (101) and (011) planes of the tetragonal ZrO2. Furthermore, the fast Fourier transform (FFT) image carried out through the 111 zone axis, attested the existence of pure tetragonal ZrO2 nanocrystals. After calcination, as expected, an expressive growth of the ZrO2 nanoparticles and the presence of uniform nanoparticles in terms of size and shape were observed (Figure 5), exhibiting a nearly spherical shape, in agreement with SEM results (Figure 4a), and dis- playing an average particle size of 45.7 ± 9.9 nm. Figure 5e,f reveal that the measured lattice spacings of 0.32 and 0.37 nm are in good agreement with the d-spacing of the 111 and (011) planes of the monoclinic ZrO2 phase, respectively. The FFT image captured through the 011 zone axis (Figure 5f) also confirmed the existence of pure monoclinic ZrO2 nanocrystals. From TEM measurements, it was observed that the monoclinic ZrO2PDF Image | Comparison between Solution-Based Synthesis Methods of ZrO2
PDF Search Title:
Comparison between Solution-Based Synthesis Methods of ZrO2Original File Name Searched:
energies-15-06452.pdfDIY PDF Search: Google It | Yahoo | Bing
Turbine and System Plans CAD CAM: Special for this month, any plans are $10,000 for complete Cad/Cam blueprints. License is for one build. Try before you buy a production license. More Info
Waste Heat Power Technology: Organic Rankine Cycle uses waste heat to make electricity, shaft horsepower and cooling. More Info
All Turbine and System Products: Infinity Turbine ORD systems, turbine generator sets, build plans and more to use your waste heat from 30C to 100C. More Info
CO2 Phase Change Demonstrator: CO2 goes supercritical at 30 C. This is a experimental platform which you can use to demonstrate phase change with low heat. Includes integration area for small CO2 turbine, static generator, and more. This can also be used for a GTL Gas to Liquids experimental platform. More Info
Introducing the Infinity Turbine Products Infinity Turbine develops and builds systems for making power from waste heat. It also is working on innovative strategies for storing, making, and deploying energy. More Info
Need Strategy? Use our Consulting and analyst services Infinity Turbine LLC is pleased to announce its consulting and analyst services. We have worked in the renewable energy industry as a researcher, developing sales and markets, along with may inventions and innovations. More Info
Made in USA with Global Energy Millennial Web Engine These pages were made with the Global Energy Web PDF Engine using Filemaker (Claris) software.
Sand Battery Sand and Paraffin for TES Thermo Energy Storage More Info
CONTACT TEL: 608-238-6001 Email: greg@infinityturbine.com (Standard Web Page)