Effect of high-content Yttria on the thermal expansion behaviour and ionic conductivity of a stabilised cubic Hafnia
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Article de revue
Este ítem está publicado en
Journal of the European Ceramic Society. 2020, vol. 40, n° 15, p. 5859-5869
Resumen en inglés
The needs for space propulsion thruster induce the development of new designs and material compositions able to withstand 3000 K of flame combustion temperature. Cubic-stabilised hafnia appears as one of the most promising ...Leer más >
The needs for space propulsion thruster induce the development of new designs and material compositions able to withstand 3000 K of flame combustion temperature. Cubic-stabilised hafnia appears as one of the most promising candidates to protect refractory materials in such conditions. Here, the influence of dopant content on the thermal expansion (473−1823 K) and ionic conductivity (600−1150 K) in highly doped-hafnia (12−33 mol% Y2O3) with disordered cubic systems is reported. The composition and the homogeneity of the samples were carefully checked using crystallographic, chemical and spectroscopy analyses. Finally, the study of thermal and oxygen conductivity properties highlighted their dependence on the amount of dopant. The average thermal expansion coefficient was lowered from 11.3 to 10.9 10−6/K and the ionic conductivity decreased by two decades with 33 mol% of Y2O3 by using the optimised substitution ratio. Interactions and local ordering of oxygen vacancies can explain this behaviour.< Leer menos
Palabras clave en inglés
Yttria doped hafnia
Fluorite
Thermal expansion coefficient (TEC)
Ionic
conductivity
Centros de investigación