scholarly journals Effects of Dopant Metal Variation and Material Synthesis Method on the Material Properties of Mixed Metal Ferrites in Yttria Stabilized Zirconia for Solar Thermochemical Fuel Production

2015 ◽  
Vol 2015 ◽  
pp. 1-10 ◽  
Author(s):  
Jeffrey Leonard ◽  
Nichole Reyes ◽  
Kyle M. Allen ◽  
Kelvin Randhir ◽  
Like Li ◽  
...  
Keyword(s):  
Synthesis Method ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Process ◽  
Synthesis Methods ◽  
Stabilized Zirconia ◽  
Fuel Production ◽  
Solid State Method ◽  
Wet Chemistry ◽  
Mixed Metal ◽  
Solar Thermochemical

Mixed metal ferrites have shown much promise in two-step solar-thermochemical fuel production. Previous work has typically focused on evaluating a particular metal ferrite produced by a particular synthesis process, which makes comparisons between studies performed by independent researchers difficult. A comparative study was undertaken to explore the effects different synthesis methods have on the performance of a particular material during redox cycling using thermogravimetry. This study revealed that materials made via wet chemistry methods and extended periods of high temperature calcination yield better redox performance. Differences in redox performance between materials made via wet chemistry methods were minimal and these demonstrated much better performance than those synthesized via the solid state method. Subsequently, various metal ferrite samples (NiFe2O4, MgFe2O4, CoFe2O4, and MnFe2O4) in yttria stabilized zirconia (8YSZ) were synthesized via coprecipitation and tested to determine the most promising metal ferrite combination. It was determined that 10 wt.% CoFe2O4in 8YSZ produced the highest and most consistent yields of O2and CO. By testing the effects of synthesis methods and dopants in a consistent fashion, those aspects of ferrite preparation which are most significant can be revealed. More importantly, these insights can guide future efforts in developing the next generation of thermochemical fuel production materials.

Study on Preparation and Properties of Yttria Stabilized Zirconia Solid State Electrolyte

2013 ◽  
Vol 544 ◽  
pp. 64-67
Author(s):  
Wei Liu ◽  
Ge Ming Liu ◽  
Niu Sheng Peng ◽  
Da Zhi Sun
Keyword(s):  
Solid State ◽  
Ionic Conductivity ◽  
Impedance Spectroscopy ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Methods ◽  
Stabilized Zirconia ◽  
Solid State Electrolyte ◽  
Spectroscopy Measurement ◽  
Basic Performance

Abstract. Currently, Yttria-stabilized zirconia solid state electrolyte are widely used in various fields . The basic performance of Yttria-stabilized zirconia (5YSZ) prepared by different synthesis methods and sintering temperatures are studied in this paper ,their phase compositions and microstructure are studied with XRD and SEM. The ionic conductivity of 5YSZ sintered at different temperature are studied with A.C. impedance spectroscopy measurement.

Synthesis of Yttria-Stabilized Zirconia Particles by Flame Spray Pyrolysis Method

2012 ◽  
Vol 629 ◽  
pp. 70-74
Author(s):  
Xiong Zhou ◽  
Wen Jun Kong
Keyword(s):  
Spray Pyrolysis ◽  
Synthesis Method ◽  
Precursor Solution ◽  
Yttria Stabilized Zirconia ◽  
Flame Spray Pyrolysis ◽  
Spray Pyrolysis Method ◽  
Flame Spray ◽  
Stabilized Zirconia ◽  
Barrier Coating ◽  
Size And Morphology

This paper presented a novel synthesis method for yttria-stabilized zirconia (YSZ) by using the flame spray pyrolysis (FSP) method. Spherical and dense YSZ particles for thermal barrier coating were successfully synthesized by FSP from the nebulized precursor solution. XRD results revealed that the YSZ powder is only composed of tetragonal phase particles. Most particles are a few hundred nanometers in diameter and their sizes are mainly dependent on the concentration of the precursor solution, while flame condition has little effect. Particle size and morphology are greatly affected by the precursor composition. Particles synthesized from ethanol precursor solution are more uniform and better-defined than those from aqueous solution.

Synthesis of Scandia, Yttria Stabilized Zirconia (SYSZ) Nanoparticles by New Wet Chemistry Method

2012 ◽  
Vol 8 (5) ◽  
pp. 767-775 ◽  
Author(s):  
Mohammad Reza Loghman-Estarki ◽  
Reza Shoja Razavi ◽  
Hossein Edris
Keyword(s):  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Wet Chemistry ◽  
Chemistry Method

scholarly journals Compositional and operational impacts on the thermochemical reduction of CO2 to CO by iron oxide/yttria-stabilized zirconia

RSC Advances ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 1493-1502
Author(s):  
Eric N. Coker ◽  
Andrea Ambrosini ◽  
James E. Miller
Keyword(s):  
Iron Oxide ◽  
Redox Chemistry ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Synthetic Fuels ◽  
Active Materials ◽  
Thermochemical Reduction ◽  
Solar Thermochemical ◽  
Reduction Of Co2 ◽  
Operational Impacts

The versatile redox chemistry of ferrites makes them useful as active materials for the solar-thermochemical production of synthetic fuels. Optimization of the distribution of iron in a YSZ matrix allows the performance of ferrites to be enhanced.

Influence of Synthesis Route on Phase Formation and Sinterability of Hydroxyapatite-Zirconia Composites

2008 ◽  
Vol 591-593 ◽  
pp. 722-727
Author(s):  
Dolores Ribeiro Ricci Lazar ◽  
Sandra Maria Cunha ◽  
Valter Ussui ◽  
E. Fancio ◽  
Nelson Batista de Lima ◽  
...  
Keyword(s):  
Chemical Reactivity ◽  
Ammonium Hydroxide ◽  
Rietveld Analysis ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Process ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Ammonium Hydrogen ◽  
Ammonium Hydrogen Phosphate ◽  
Diffraction Patterns

Reinforcement with yttria stabilized zirconia (YSZ) is an alternative to improve mechanical strength of hydroxyapatite (HAp) ceramic. However, calcium may react with zirconium to form calcium zirconate. In addition, decomposition of HAp to tricalcium phosphate (TCP) occurs with water loss inhibiting ceramic densification. In order to minimize the formation of these compounds, two synthesis routes were compared in this work: coprecipitation of hydrous yttria stabilized zirconia in a calcium phosphate gel medium and powder mixture of individual calcined powders. Composite nominal compositions were fixed at 90 and 95 HAp wt%. Calcium, zirconium and yttrium chlorides and ammonium hydrogen phosphate were the employed precursors. Ammonium hydroxide was the selected precipitation agent. Calcination was performed at 800oC for 1 hour and pellets were sintered in the range of 1150 and 1350oC for 1, 3 and 5 hours. Ceramic samples were characterized by scanning electron microscopy and apparent density measurements. Crystalline phases were quantified by Rietveld analysis of X-ray diffraction patterns. Results indicate that powders prepared by coprecipitation can cause porosity formation due to the higher chemical reactivity during synthesis process.

scholarly journals An Analysis of Distance Education Problems Experienced in Higher Education: A Meta-Synthesis Study

2021 ◽  
Vol 11 ◽  
Author(s):  
Güngör Kil ◽  
Salih Uşun
Keyword(s):  
Higher Education ◽  
Distance Education ◽  
Synthesis Method ◽  
Learning Problems ◽  
Synthesis Process ◽  
Synthesis Methods ◽  
Financial Problems ◽  
Web Based ◽  
E Learning ◽  
Synthesis Approach

By using the meta-synthesis method, this study aims to analyze the studies on distance education problems experienced in higher education. The data were gathered by using the "higher education problems", "e-learning problems", "online learning problems", "open education problems", "web-based learning problems" keywords in Google Academic and TUBITAK ULAKBIM (https://ulakbim.tubitak.gov.tr/) databases. A total of 23 articles meeting the predetermined criteria were included in the study. These articles were analyzed by using the thematic synthesis approach, one of the meta-synthesis methods. The meta-synthesis process developed by Walsh and Downe (2005) was followed in the analysis. Established codes and themes were presented in frequency tables and interpreted. The distance education problems experienced in higher education were discussed under five categories as the "problems relevant to students", "problems relevant to instructors", "systemic and administrative problems", "problems relevant to curriculum", and "infrastructure and financial problems". Among these problems, the "problems relevant to students" category was found to have the highest frequency while the "infrastructure and financial problems" had the lowest frequency.

Synthesis of yttria-stabilized zirconia nanoparticles by decomposition of metal nitrates coated on carbon powder

1996 ◽  
Vol 11 (9) ◽  
pp. 2318-2324 ◽  
Author(s):  
Shusheng Jiang ◽  
Gregory C. Stangle ◽  
Vasantha R. W. Amarakoon ◽  
Walter A. Schulze
Keyword(s):  
Carbon Black ◽  
Crystallite Size ◽  
Surface Area ◽  
Yttria Stabilized Zirconia ◽  
Synthesis Process ◽  
Carbon Powder ◽  
Stabilized Zirconia ◽  
Black Powder ◽  
Carbon Black Powder ◽  
Metal Nitrates

Weakly agglomerated nanoparticles of yttria-stabilized zirconia (YSZ) were synthesized by a novel process which involved the decomposition of metal nitrates that had been coated on ultrafine carbon black powder, after which the carbon black was gasified. The use of ultrafine, high-surface-area carbon black powder apparently allowed the nanocrystalline oxide particles to form and remain separate from each other, after which the carbon black was gasified at a somewhat higher temperature. As a result, the degree of agglomeration was shown to be relatively low. The average crystallite size and the specific surface area of the as-synthesized YSZ nanoparticles were 5−6 nm and 130 m2/g, respectively, for powder synthesized at 650 °C. The as-synthesized YSZ nanoparticles had a light brown color and were translucent, which differs distinctly from conventional YSZ particles which are typically white and opaque. The mechanism of the synthesis process was investigated, and indicated that the gasification temperature had a direct effect on the crystallite size of the as-synthesized YSZ nanoparticles. High-density and ultrafine-grained YSZ ceramic articles were prepared by fast-firing, using a dwell temperature of 1250 °C and a dwell time of two minutes or less.

Microstructural examination of modified yttria stabilized zirconia by EM analytical techniques

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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