Phase development and pore stability of yttria‐ and ytterbia‐stabilized zirconia aerogels

Recent studies have shown that spray-pyrolyzed films of the Tl-1223 compound (TlxBa2Ca2Cu3Oy, with 0.7 < × < 0.95) on polycrystalline yttrium stabilized zirconia substrates can be prepared which have critical current density Jc near 105 A/cm2 at 77 K, in zero field. The films are polycrystalline, have excellent c-axis alignment, and show little evidence of weak-link behavior. Transmission electron microscopy (TEM) studies have shown that most grain boundaries have small misorientation angles. It has been found that the films have a nigh degree of local texture indicative of colonies of similarly oriented grains. It is believed that inter-colony conduction is enhanced by a percolative network of small angle boundaries at colony interfaces. It has also been found that Jc is increased by a factor of 4 - 5 after the films were annealed at 600 °C in oxygen. This study is thus carried out to determine the effect on grain boundary chemistry of the heat treatment.

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Microstructural examination of modified yttria stabilized zirconia by EM analytical techniques

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100145558 ◽

1986 ◽

Vol 44 ◽

pp. 842-843

Author(s):

W. W. Davison ◽

R. C. Buchanan

Keyword(s):

Mechanical Properties ◽

Analytical Techniques ◽

Yttria Stabilized Zirconia ◽

Stabilized Zirconia ◽

Transmission Microscopy ◽

Sintering Aid ◽

Densification Temperature ◽

Chemical Inertness ◽

Scanning Transmission ◽

Microstructural Examination

Yttria stabilized zirconia (YSZ) has become a significant technological material due to its high ionic conductivity, chemical inertness, and good mechanical properties. Temperatures on the order of 1700°C are required, however, to densify YSZ to the degree necessary for good electrical and mechanical properties. A technique for lowering the densification temperature is the addition of small amounts of material which facilitate the formation of a liquid phase at comparatively low temperatures. In this study, sintered microstructures obtained from the use of Al2O3 as a sintering aid were examined with scanning, transmission, and scanning transmission microscopy (SEM, TEM, and STEM).

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Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

Engineering and Technology Journal ◽

10.30684/etj.v38i4a.351 ◽

2020 ◽

Vol 38 (4A) ◽

pp. 491-500

Author(s):

Abeer F. Al-Attar ◽

Saad B. H. Farid ◽

Fadhil A. Hashim

Keyword(s):

Ionic Conductivity ◽

Electrochemical Impedance ◽

Structural Information ◽

Impedance Analysis ◽

High Energy ◽

Yttria Stabilized Zirconia ◽

X Ray Diffraction ◽

Stabilized Zirconia ◽

Powder Morphology ◽

X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

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Preparation of Magnesia Stabilized Zirconia Thin Films for Solid Oxide Fuel Cell by Microwave Plasma Chemical Vapor Deposition.

Shinku ◽

10.3131/jvsj.40.660 ◽

1997 ◽

Vol 40 (8) ◽

pp. 660-663

Author(s):

Hideo OKAYAMA ◽

Tsukasa KUBO ◽

Noritaka MOCHIZUKI ◽

Akiyoshi NAGATA ◽

Hiromu ISA

Keyword(s):

Thin Films ◽

Fuel Cell ◽

Vapor Deposition ◽

Microwave Plasma ◽

Chemical Vapor ◽

Solid Oxide ◽

Oxide Fuel ◽

Stabilized Zirconia ◽

Plasma Chemical ◽

Plasma Chemical Vapor Deposition

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Maximum Temperature Through a Yttrium Stabilized Zirconia Ceramic After Er,Cr:YSGG Laser Irradiation

Current Dentistry ◽

10.2174/2542579x02999200806160149 ◽

2020 ◽

Vol 02 ◽

Author(s):

Laurel Stringer ◽

Sarah Malley ◽

Darrell M. Hutto ◽

Jason A. Griggs ◽

Susana M. Salazar Marocho

Keyword(s):

High Speed ◽

Potential Method ◽

Maximum Temperature ◽

Zirconia Ceramic ◽

Tooth Pulp ◽

Control Group ◽

Stabilized Zirconia ◽

Significant Difference ◽

Power Setting ◽

Group A

Background: The most common approach to remove yttria stabilized zirconia (YSZ) fixed-dental prostheses (FDPs) is by means of diamond burs attached to a high-speed handpiece. This process is time-consuming and destructive. The use of lasers over mechanical instrumentation for removal of FDPs can lead to efficient and predictable restoration retrievability. However, the heat produced might damage the tooth pulp (>42˚C). Objective: The purpose of this study was to determine the maximum temperature (T) reached during the use of different settings of the erbium, chromium:yttrium-scandium-gallium-garnet Er,Cr:YSGG laser through a YSZ ceramic. Methods: YSZ slices (1 mm thick) were assigned into 7 groups. For the control group, a diamond bur was used to cut a 1 mm groove into the YSZ slices. For the 6 experimental groups, the laser was operated at a constant combination of 33% water and 66% air during 30 s with two different power settings (W) at three frequencies (PPS), as follows (W/PPS): 2.5/20, 2.5/30, 2.5/45, 4.5/20, 4.5/30, 4.5/45. The T through the YSZ slice was recorded in degrees Celsius by using a digital thermometer with a K thermocouple. Results: The median T of the control group was 26.5˚C. The use of 4.5 W resulted in the median T (˚C) of 44.2 at 20 PPS, 53.3 at 30 PPS, and 58.9 at 45 PPS, while 2.5 W showed 34.6, 31.6, and 25.0 at 20, 30, and 45 PPS, respectively. KruskalWallis one-way ANOVA showed that within each power setting, the T was similar. The high power and lowest frequency (4.5/20) showed no significant difference from the 2.5 W settings and the control group. Conclusion: The lower power setting (2.5 W) is a potential method for the use of the Er,Cr:YSGG laser to debond YSZ structures. The higher power (4.5 W) with high frequencies (30 and 45 PPS) is unsuitable.

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Pola Implementasi Gerakan Literasi Sekolah Di SMP Negeri 5 Malang

Jurnal Kebijakan dan Pengembangan Pendidikan ◽

10.22219/jkpp.v8i1.11237 ◽

2020 ◽

Vol 8 (1) ◽

Author(s):

Syaiful Rahman

Keyword(s):

High School ◽

Junior High School ◽

Reading Ability ◽

Qualitative Approach ◽

School Resources ◽

Development Phase ◽

Writing Ability ◽

Habituation Phase ◽

Phase Development ◽

Pattern Of Implementation

Abstract: The students 'reading ability is low, it certainly affects the students' writing ability. Implementation of the School Literacy Movement is a solution to students' low reading ability. This study aims to describe the pattern of Implementation of School Literacy Movement that took place in SMP Negeri 5 Malang. This study uses a qualitative approach with a descriptive type that describes the School Literacy Movement in SMP Negeri 5 Malang. Data collection techniques using observation, interviews, and documentation. The results showed that the pattern of implementation of school literacy measures in SMP Negeri 5 Malang included: 1) The habituation phase was carried out by way of students bringing reading books from home or borrowing books to the library. At this stage a class reading corner was prepared, reading 15 minutes before learning began, and a literacy journal; 2) The Development and Learning Phase increases the school resources especially at the State Junior High School 5 Malang, namely the existence of a reading corner in each class, an increase in the number of books, a 30-minute reading club, and a product of the School Literacy Movement.Keywords: School Literacy Movement, Habituation Phase, Development Phase, LearningAbstrak: Kemampuan membaca peserta didik tergolong rendah pasti berpengaruh terhadap kemampuan menulis peserta didik. Implementasi Gerakan Literasi Sekolah menjadi solusi atas kemampuan membaca siswa yang rendah. Penelitian ini bertujuan untuk mendeskripsikan pola Implementasi Gerakan Literasi Sekolah yang berlangsung di SMP Negeri 5 Malang. Penelitian ini menggunakan pendekatan kualitatif dengan jenis deskriptif yang mendeksripsikan Gerakan Literasi Sekolah di SMP Negeri 5 Malang. Teknik pengumpulan data menggunakan observasi, wawancara, dan dokumentasi. Hasil penelitian menunjukan bahwa pola implementasi geakan literasi sekolah di SMP Negeri 5 Malang meliputi: 1) Tahap Pembiasaan dilaksanakan dengan cara peserta didik membawa buku bacaan dari rumah atau meminjam buku ke perpustakaan. Pada tahap ini sudah disiapkan pojok baca kelas, membaca 15 menit sebelum pembelajaran dimulai, dan jurnal literas; 2) Tahap Pengembangan dan Pembelajaran meningkatkan sumber daya sekolah khusnya di Sekolah Menengah Pertama Negeri 5 Malang yaitu adanya pojok baca di masing-masing kelas, penambahan jumlah buku, adanya club baca 30 menit, dan hasil produk Gerakan Literasi Sekolah.Kata Kunci: Gerakan Literasi Sekolah, Tahap Pembiasaan, Tahap Pengembangan, Pembelajaran

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