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On the influence of silica type on the structural integrity of dense La9.33Si2Ge4O26 electrolytes for SOFCs

dc.contributor.authorAlves, Cátia
dc.contributor.authorMarcelo, Teresa
dc.contributor.authorOliveira, Fernando Almeida Costa
dc.contributor.authorAlves, L. C.
dc.contributor.authorMascarenhas, João
dc.contributor.authorTrindade, B.
dc.date.accessioned2013-12-17T15:02:58Z
dc.date.available2013-12-17T15:02:58Z
dc.date.issued2013
dc.description.abstractApatite-type rare earth based oxides, such as R-doped lanthanum oxides of general formula La9.33(RO4)6O2 with R = Ge, Si, exhibit high ionic conductivity and low activation energy at moderate temperatures, when compared to the yttria-stabilized zirconia electrolyte making them potential materials to be used in the range 500–700 °C, for intermediate temperature solid oxide fuel cells (IT-SOFCs). In this study, dense oxyapatite-based La9.33Si2Ge4O26 electrolytes have been successfully prepared either by electrical sintering at 1400 °C or microwave hybrid sintering at 1350 °C for 1 h from La2O3, SiO2 and GeO2 powders dry milled at 350 rpm for 15 h in a planetary ball mill. The densification behaviour of the apatite-type phase synthesized by mechanical alloying was found to be dependent on the grade of SiO2 used: either pre-milled quartz powder or amorphous nanosized fumed silica. The influence of the silica type on the La9.33Si2Ge4O26 integrity was assessed by dynamic Young's modulus, microhardness and indentation fracture toughness measurements. A good correlation between the degree of densification (as observed by SEM/EDS) and the resulting mechanical properties could be established. Pre-milling of quartz powder has favoured higher densification rates to be attained suggesting that both Fe content, resulting from the dry milling (as determined by PIXE analyses) and crystallinity of SiO2 do promote densification of these electrolytes thereby improving their structural integrity.por
dc.identifier.citationAlves, C.; Marcelo, T.; Oliveira, F.A.C.; Alves, L.C.; Mascarenhas, J.; Trindade, B. On the influence of silica type on the structural integrity of dense La9.33Si2Ge4O26 electrolytes for SOFCs. In:Journal of the European Ceramic Society, 2013, Vol. 33, nº 12, p. 2251-2258por
dc.identifier.issn0955-2219
dc.identifier.urihttp://hdl.handle.net/10400.9/2094
dc.language.isoengpor
dc.publisherElsevierpor
dc.relation.publisherversionhttp://dx.doi.org/10.1016/j.jeurceramsoc.2012.12.024por
dc.subjectOxyapatitepor
dc.subjectElectrolytespor
dc.subjectIT-SOFCpor
dc.subjectMechanical propertiespor
dc.subjectMicrowave Sinteringpor
dc.titleOn the influence of silica type on the structural integrity of dense La9.33Si2Ge4O26 electrolytes for SOFCspor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage2258por
oaire.citation.startPage2251por
oaire.citation.titleJournal of the European Ceramic Societypor
oaire.citation.volume33por
person.familyNameOliveira
person.familyNameMascarenhas
person.givenNameFernando
person.givenNameJoão
person.identifier647144
person.identifier.ciencia-id561B-597F-9D55
person.identifier.ciencia-idCF18-4E59-B6B9
person.identifier.orcid0000-0002-1503-0152
person.identifier.orcid0000-0003-0440-8057
person.identifier.ridA-2312-2011
person.identifier.ridL-3318-2014
person.identifier.scopus-author-id23019925500
rcaap.rightsopenAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublication2c841cae-13ca-44f6-8cb1-b5ce93608bae
relation.isAuthorOfPublication1b345025-eb12-4019-ab1c-e7b3b23962a8
relation.isAuthorOfPublication.latestForDiscovery1b345025-eb12-4019-ab1c-e7b3b23962a8

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