Markets for Chemical Expansion

1954 ◽  
Vol 46 (11) ◽  
pp. 2319-2321
Author(s):  
H. E. Wessel
Keyword(s):  
Chemical Expansion

Crystal structure, chemical expansion and phase stability of HoMnO3 at high temperature

2012 ◽  
Vol 196 ◽  
pp. 528-535 ◽  
Author(s):  
Sverre M. Selbach ◽  
Amund Nordli Løvik ◽  
Kristin Bergum ◽  
Julian R. Tolchard ◽  
Mari-Ann Einarsrud ◽  
...  
Keyword(s):  
Crystal Structure ◽  
High Temperature ◽  
Phase Stability ◽  
Chemical Expansion

Chemical expansion of nonstoichiometric Pr0.1Ce0.9O2−δ: Correlation with defect equilibrium model

2011 ◽  
Vol 31 (13) ◽  
pp. 2351-2356 ◽  
Author(s):  
Sean R. Bishop ◽  
Harry L. Tuller ◽  
Yener Kuru ◽  
Bilge Yildiz
Keyword(s):  
Equilibrium Model ◽  
Chemical Expansion

scholarly journals Redox Oxides-Based Solar Thermochemistry and Its Materialization to Reactor/Heat Exchanger Concepts for Efficient Solar Energy Harvesting, Transformation and Storage

2019 ◽  
Vol 141 (2) ◽  
Author(s):  
Christos Agrafiotis ◽  
Mathias Pein ◽  
Dimitra Giasafaki ◽  
Stefania Tescari ◽  
Martin Roeb ◽  
...  
Keyword(s):  
Scanning Calorimetry ◽  
Chemical Expansion ◽  
Solar Energy Harvesting ◽  
Cyclic Operation ◽  
Heat Effects ◽  
Carbon Dioxide Splitting ◽  
Oxygen Pumping ◽  
Coefficient Of Linear Expansion ◽  
A Site

Ca-Mn-based perovskites doped in their A- and B-site were synthesized and comparatively tested versus the Co3O4/CoO and (Mn,Fe)2O3/(Mn,Fe)3O4 redox pairs with respect to thermochemical storage and oxygen pumping capability, as a function of the kind and extent of dopant. The perovskites' induced heat effects measured via differential scanning calorimetry are substantially lower: the highest reaction enthalpy recorded by the CaMnO3–δ composition was only 14.84 kJ/kg compared to 461.1 kJ/kg for Co3O4/CoO and 161.0 kJ/kg for (Mn,Fe)2O3/(Mn,Fe)3O4. Doping of Ca with increasing content of Sr decreased these heat effects; more than 20 at % Sr eventually eliminated them. Perovskites with Sr instead of Ca in the A-site exhibited also negligible heat effects, irrespective of the kind of B site cation. On the contrary, perovskite compositions characterized by high oxygen release/uptake can operate as thermochemical oxygen pumps enhancing the performance of water/carbon dioxide splitting materials. Oxygen pumping via Ca0.9Sr0.1MnO3–δ and SrFeO3–δ doubled and tripled, respectively, the total oxygen absorbed by ceria during its re-oxidation versus that absorbed without their presence. Such effective pumping compositions exhibited practically no shrinkage during one heat-up/cool-down cycle. However, they demonstrated an increase of the coefficient of linear expansion due to the superposition of “chemical expansion” to thermal-only one, the effect of which on the long-term dimensional stability has to be further quantified through extended cyclic operation.

scholarly journals Chemical expansion of praseodymium-cerium oxide films at high temperatures by laser doppler vibrometry

2018 ◽  
Vol 319 ◽  
pp. 61-67 ◽  
Author(s):  
Silja Schmidtchen ◽  
Holger Fritze ◽  
Sean Bishop ◽  
Di Chen ◽  
Harry L. Tuller
Keyword(s):  
Cerium Oxide ◽  
High Temperatures ◽  
Oxide Films ◽  
Laser Doppler ◽  
Laser Doppler Vibrometry ◽  
Chemical Expansion

Phase Transitions, Chemical Expansion, and Deuteron Sites in the BaZr0.7Ce0.2Y0.1O3−δ Proton Conductor

2016 ◽  
Vol 28 (12) ◽  
pp. 4292-4299 ◽  
Author(s):  
Glenn C. Mather ◽  
Gemma Heras-Juaristi ◽  
Clemens Ritter ◽  
Rodolfo O. Fuentes ◽  
Adilson L. Chinelatto ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Proton Conductor ◽  
Chemical Expansion

scholarly journals Thin-film chemical expansion of ceria based solid solutions: laser vibrometry study

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hendrik Wulfmeier ◽  
Dhyan Kohlmann ◽  
Thomas Defferriere ◽  
Carsten Steiner ◽  
Ralf Moos ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
High Temperature ◽  
Film Thickness ◽  
Solid Solutions ◽  
Low Voltage ◽  
Excitation Frequency ◽  
Dimensional Change ◽  
Potential Core ◽  
Chemical Expansion

Abstract The chemical expansion of Pr0.1Ce0.9O2–δ (PCO) and CeO2–δ thin films is investigated in the temperature range between 600 °C and 800 °C by laser Doppler vibrometry (LDV). It enables non-contact determination of nanometer scale changes in film thickness at high temperatures. The present study is the first systematic and detailed investigation of chemical expansion of doped and undoped ceria thin films at temperatures above 650 °C. The thin films were deposited on yttria stabilized zirconia substrates (YSZ), operated as an electrochemical oxygen pump, to periodically adjust the oxygen activity in the films, leading to reversible expansion and contraction of the film. This further leads to stresses in the underlying YSZ substrates, accompanied by bending of the overall devices. Film thickness changes and sample bending are found to reach up to 10 and several hundred nanometers, respectively, at excitation frequencies from 0.1 to 10 Hz and applied voltages from 0–0.75 V for PCO and 0–1 V for ceria. At low frequencies, equilibrium conditions are approached. As a consequence maximum thin-film expansion of PCO is expected due to full reduction of the Pr ions. The lower detection limit for displacements is found to be in the subnanometer range. At 800 °C and an excitation frequency of 1 Hz, the LDV shows a remarkable resolution of 0.3 nm which allows, for example, the characterization of materials with small levels of expansion, such as undoped ceria at high oxygen partial pressure. As the correlation between film expansion and sample bending is obtained through this study, a dimensional change of a free body consisting of the same material can be calculated using the high resolution characteristics of this system. A minimum detectable dimensional change of 5 pm is estimated even under challenging high-temperature conditions at 800 °C opening up opportunities to investigate electro-chemo-mechanical phenomena heretofore impossible to investigate. The expansion data are correlated with previous results on the oxygen nonstoichiometry of PCO thin films, and a defect model for bulk ceria solid solutions is adopted to calculate the cation and anion radii changes in the constrained films during chemical expansion. The constrained films exhibit anisotropic volume expansion with displacements perpendicular to the substrate plane nearly double that of bulk samples. The PCO films used here generate high total displacements of several 100 nm’s with high reproducibility. Consequently, PCO films are identified to be a potential core component of high-temperature actuators. They benefit not only from high displacements at temperatures where most piezoelectric materials no longer operate while exhibiting, low voltage operation and low energy consumption.

scholarly journals High Temperature Thermo-Mechanical Properties of Praseodymium Doped Ceria Thin Films Measured Two Ways

2022 ◽  
Author(s):  
Yuxi Ma ◽  
Quan Zhou ◽  
Jason D. Nicholas
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
High Temperature ◽  
Temperature Dependence ◽  
Internal Stress ◽  
Expansion Coefficient ◽  
Mechanical Stability ◽  
Doped Ceria ◽  
Stress Strain ◽  
Chemical Expansion

The temperature dependence of a Mixed Ionic Electronic Conducting (MIEC) material’s thermo-chemical expansion coefficient, biaxial modulus, and/or Young’s modulus are crucial in determining the internal stress, strain, and/or mechanical stability...

Strongly coupled thermal and chemical expansion in the perovskite oxide system Sr(Ti,Fe)O3−α

2015 ◽  
Vol 3 (7) ◽  
pp. 3602-3611 ◽  
Author(s):  
Nicola H. Perry ◽  
Jae Jin Kim ◽  
Sean R. Bishop ◽  
Harry L. Tuller
Keyword(s):  
Energy Conversion ◽  
Oxide System ◽  
Perovskite Oxide ◽  
Oxygen Stoichiometry ◽  
Temperature Dependent ◽  
Chemical Expansion ◽  
Strongly Coupled ◽  
Expansion Coefficients ◽  
Energy Conversion Devices ◽  
First Time

To evaluate stability in energy conversion devices, thermal and chemical expansion coefficients (CTE, CCE) of Sr(Ti,Fe)O3−α were measured and deconvoluted for the first time, revealing an oxygen stoichiometry-dependent CTE and temperature-dependent CCE.

Sign in / Sign up

Export Citation Format

Share Document