The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias
The powder characteristics of the following 8 mol% yttria-stabilised zirconia samples were studied: Tioxide yttria-coated zirconia (coated-YSZ), Tioxide co-milled YSZ, Tosoh co-precipitated YSZ and A YSZ prepared in-house by a conventional solid state route. Co-milled YSZ powders containing 3-11 mol...
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ndltd-bl.uk-oai-ethos.bl.uk-3097962017-04-20T03:32:25ZThe characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconiasGibson, Iain R.1995The powder characteristics of the following 8 mol% yttria-stabilised zirconia samples were studied: Tioxide yttria-coated zirconia (coated-YSZ), Tioxide co-milled YSZ, Tosoh co-precipitated YSZ and A YSZ prepared in-house by a conventional solid state route. Co-milled YSZ powders containing 3-11 mol% yttria were also studied. The phase assemblage of as-received and reacted powders was investigated by XRD. As-received co-precipitated YSZ was cubic single phase. All other as-received powders consisted of a mixture of yttria and monoclinic zirconia. The phase evolution of the samples between 1000 and 1500° was studied. The coated and co-milled YSZ were cubic single phase only after reaction at 1300°. The rate at which the different powders reached equilibrium on heating decreased in the sequence: coated-YSZ > co-milled YSZ>YSZ prepared in-house. This difference in reactivity is discussed in terms of the yttria distribution in the as-received powder. A detailed study of the yttria-zirconia reaction in coated-YSZ was made. A model was devised to describe the counter-diffraction of yttria from the external coating and the zirconia. TEM analysis of a partially-reacted coated-YSZ sample showed that some grains contained to tetragonal inner core surrounded by a cubic outer shell. The kinetics of the yttria-zirconia reaction were studied: an activation energy of 470-555 kJmol-1 was determined, which was attributed to cation counter-diffusion. The formation of the metastable t'-phase in YSZ samples was studied. On rapid-cooling, cubic YSZ solid solutions containing between 3 and 7.7 mol% yttria transformed to the t'-phase: for compositions greater than 7.7 mol% the cubic solid solutions were retained to room temperature.530.41Solid-state physicsUniversity of Aberdeenhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309796http://digitool.abdn.ac.uk/R?func=search-advanced-go&find_code1=WSN&request1=AAIU527983Electronic Thesis or Dissertation |
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530.41 Solid-state physics |
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530.41 Solid-state physics Gibson, Iain R. The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
description |
The powder characteristics of the following 8 mol% yttria-stabilised zirconia samples were studied: Tioxide yttria-coated zirconia (coated-YSZ), Tioxide co-milled YSZ, Tosoh co-precipitated YSZ and A YSZ prepared in-house by a conventional solid state route. Co-milled YSZ powders containing 3-11 mol% yttria were also studied. The phase assemblage of as-received and reacted powders was investigated by XRD. As-received co-precipitated YSZ was cubic single phase. All other as-received powders consisted of a mixture of yttria and monoclinic zirconia. The phase evolution of the samples between 1000 and 1500° was studied. The coated and co-milled YSZ were cubic single phase only after reaction at 1300°. The rate at which the different powders reached equilibrium on heating decreased in the sequence: coated-YSZ > co-milled YSZ>YSZ prepared in-house. This difference in reactivity is discussed in terms of the yttria distribution in the as-received powder. A detailed study of the yttria-zirconia reaction in coated-YSZ was made. A model was devised to describe the counter-diffraction of yttria from the external coating and the zirconia. TEM analysis of a partially-reacted coated-YSZ sample showed that some grains contained to tetragonal inner core surrounded by a cubic outer shell. The kinetics of the yttria-zirconia reaction were studied: an activation energy of 470-555 kJmol-1 was determined, which was attributed to cation counter-diffusion. The formation of the metastable t'-phase in YSZ samples was studied. On rapid-cooling, cubic YSZ solid solutions containing between 3 and 7.7 mol% yttria transformed to the t'-phase: for compositions greater than 7.7 mol% the cubic solid solutions were retained to room temperature. |
author |
Gibson, Iain R. |
author_facet |
Gibson, Iain R. |
author_sort |
Gibson, Iain R. |
title |
The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
title_short |
The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
title_full |
The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
title_fullStr |
The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
title_full_unstemmed |
The characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
title_sort |
characterisation and electrical properties of novel 8 mol% yttria-stabilised zirconias |
publisher |
University of Aberdeen |
publishDate |
1995 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.309796 |
work_keys_str_mv |
AT gibsoniainr thecharacterisationandelectricalpropertiesofnovel8molyttriastabilisedzirconias AT gibsoniainr characterisationandelectricalpropertiesofnovel8molyttriastabilisedzirconias |
_version_ |
1718441444552736768 |