The synthesis of beta alumina powders

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dc.contributor.advisorHeckroodt, Oelofen_ZA
dc.contributor.authorVan Zyl, Arnolden_ZA
dc.date.accessioned2016-03-11T14:24:18Z
dc.date.available2016-03-11T14:24:18Z
dc.date.issued1987en_ZA
dc.descriptionBibliography: pages 83-90.en_ZA
dc.description.abstractBeta alumina solid electrolyte material is conventionally synthesized by the high temperature solid state reaction of α-Al₂O₃ with soda and a stabilizer ion such as lithia or magnesia. This reaction requires a reconstructive transformation of the α-Al₂O₃ oxygen sublattice and results in a two-phase mixture of β and β"-Al₂O. In order to maximize the preferred β"-Al₂O₃ phase an additional peak heat treatment schedule is required. This work investigated the replacement of the α-Al ₂O₃ component of the reaction mixture with a range of synthetic aluminium hydroxide precursor materials. Four different aluminium hydroxide precursors were synthesized by the controlled hydrolysis of a common aluminium isopropoxide parent material. The oxygen sublattice of each aluminium hydroxide precursor was engineered by varying the alkoxide hydrolysis conditions. These precursors were used to synthesize beta alumina powders by the high temperature solid state reaction with soda and lithia, resulting in powders with a nominal composition of Li₀.₃₈Na₁.₆₅Al₁₀.₆₆O₁₇. The solid state reactions were monitored by differential thermal analysis and thermogravimetric analysis. The structural development of the reaction products with increasing temperature, was monitored by powder X-ray diffraction. A significant observation was the direct formation of single phase β"-Al₂O₃ at 1200 °C by the solid state reaction of soda and lithia with certain aluminium hydroxides. The work concludes with the proposal of a generalized mechanism relating the aluminium hydroxide precursor oxygen sublattice to the nature of the beta alumina reaction product.en_ZA
dc.identifier.apacitationVan Zyl, A. (1987). <i>The synthesis of beta alumina powders</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/17648en_ZA
dc.identifier.chicagocitationVan Zyl, Arnold. <i>"The synthesis of beta alumina powders."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1987. http://hdl.handle.net/11427/17648en_ZA
dc.identifier.citationVan Zyl, A. 1987. The synthesis of beta alumina powders. University of Cape Town.en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Van Zyl, Arnold AB - Beta alumina solid electrolyte material is conventionally synthesized by the high temperature solid state reaction of α-Al₂O₃ with soda and a stabilizer ion such as lithia or magnesia. This reaction requires a reconstructive transformation of the α-Al₂O₃ oxygen sublattice and results in a two-phase mixture of β and β"-Al₂O. In order to maximize the preferred β"-Al₂O₃ phase an additional peak heat treatment schedule is required. This work investigated the replacement of the α-Al ₂O₃ component of the reaction mixture with a range of synthetic aluminium hydroxide precursor materials. Four different aluminium hydroxide precursors were synthesized by the controlled hydrolysis of a common aluminium isopropoxide parent material. The oxygen sublattice of each aluminium hydroxide precursor was engineered by varying the alkoxide hydrolysis conditions. These precursors were used to synthesize beta alumina powders by the high temperature solid state reaction with soda and lithia, resulting in powders with a nominal composition of Li₀.₃₈Na₁.₆₅Al₁₀.₆₆O₁₇. The solid state reactions were monitored by differential thermal analysis and thermogravimetric analysis. The structural development of the reaction products with increasing temperature, was monitored by powder X-ray diffraction. A significant observation was the direct formation of single phase β"-Al₂O₃ at 1200 °C by the solid state reaction of soda and lithia with certain aluminium hydroxides. The work concludes with the proposal of a generalized mechanism relating the aluminium hydroxide precursor oxygen sublattice to the nature of the beta alumina reaction product. DA - 1987 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1987 T1 - The synthesis of beta alumina powders TI - The synthesis of beta alumina powders UR - http://hdl.handle.net/11427/17648 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/17648
dc.identifier.vancouvercitationVan Zyl A. The synthesis of beta alumina powders. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1987 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/17648en_ZA
dc.language.isoengen_ZA
dc.publisher.departmentCentre for Materials Engineeringen_ZA
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.publisher.institutionUniversity of Cape Town
dc.subject.otherAluminum oxideen_ZA
dc.subject.otherAluminum hydroxideen_ZA
dc.titleThe synthesis of beta alumina powdersen_ZA
dc.typeDoctoral Thesis
dc.type.qualificationlevelDoctoral
dc.type.qualificationnamePhDen_ZA
uct.type.filetypeText
uct.type.filetypeImage
uct.type.publicationResearchen_ZA
uct.type.resourceThesisen_ZA
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