The kinetic of mullite crystallization: Effect of water content

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dc.contributor.authorde Oliveira, Taysa Cristina
dc.contributor.authorRibeiro, Clovis Augusto [UNESP]
dc.contributor.authorBrunelli, Deborah Dibbern
dc.contributor.authorRodrigues, Liana Alvares
dc.contributor.authorThim, Gilmar Patrocínio
dc.contributor.institutionInstituto Tecnológico de Aeronáutica (ITA)
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.date.accessioned2015-05-15T13:30:22Z
dc.date.available2015-05-15T13:30:22Z
dc.date.issued2010
dc.description.abstractThe kinetic of mullite crystallization from sol–gel method, with different water content, was investigated under non-isothermal conditions using DTA. The sols were obtained from Al(NO3)3.9H2O (ANN) and Si(OC2H5)4 (TEOS) mixtures by varying the water–alcohol content of the system. The crystalline phase changes were verified by X-ray diffraction (XRD). For a sample prepared using ethanol-based alkoxide solution (M0), only Al-poor mullite (p-mullite) crystallizes at 1000 °C; for the one synthesized with low water concentration (M6) Al-rich mullite (r-mullite) and spinel crystallize together; and for a sample prepared using a water-based alkoxide solution only spinel is formed. Thus, the variation of water contents during the synthesis caused great variations in the course of mullitization process. The average value of the apparent activation energy determined for p-mullite, r-mullite and spinel phase crystallization were found to be E = (899 ± 61) kJ mol−1, E = (1015 ± 272) kJ mol−1 and E = (980 ± 196) kJ mol−1, respectively. These results showed that sample M(0) was a monophasic gel, where aluminum and silicon atoms are mixed at a molecular level while sample M(100) was a diphasic gel, where silicon and aluminum atoms are distributed in a nanometric level. The fast reaction between TEOS and water molecules is responsible for this great difference in the sample's homogeneity. The kinetic model of the crystallization process was determined using Malek's procedure. It was established that the crystallization of p-mullite, r-mullite and spinel phase can be described by Šesták–Berggren autocatalytic model.en
dc.description.affiliationUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Química Analítica, Instituto de Química de Araraquara, Araraquara, R. PROFESSOR FRANCISCO DEGNI, S/N, QUITANDINHA, CEP 14801-970, SP, Brasil
dc.description.affiliationUnespUniversidade Estadual Paulista Júlio de Mesquita Filho, Departamento de Química Analítica, Instituto de Química de Araraquara
dc.format.extent2980-2985
dc.identifierhttp://www.sciencedirect.com/science/article/pii/S0022309310004588
dc.identifier.citationJournal of Non-Crystalline Solids, v. 356, p. 2980-2985, 2010.
dc.identifier.doi10.1016/j.jnoncrysol.2010.05.078
dc.identifier.issn0022-3093
dc.identifier.lattes8498310891810082
dc.identifier.lattes8228249846548127
dc.identifier.lattes9324788138817522
dc.identifier.orcid0000-0002-7984-5908
dc.identifier.urihttp://hdl.handle.net/11449/123531
dc.language.isoeng
dc.relation.ispartofJournal of Non-Crystalline Solids
dc.relation.ispartofjcr2.488
dc.relation.ispartofsjr0,722
dc.rights.accessRightsAcesso restrito
dc.sourceCurrículo Lattes
dc.subjectMulliteen
dc.subjectCrystallizationen
dc.subjectNon Isothermal Kineticen
dc.subjectsol-gelen
dc.titleThe kinetic of mullite crystallization: Effect of water contenten
dc.typeArtigo
unesp.author.lattes8228249846548127
unesp.author.lattes9324788138817522
unesp.author.lattes8498310891810082[2]
unesp.author.orcid0000-0002-7984-5908[2]
unesp.campusUniversidade Estadual Paulista (Unesp), Instituto de Química, Araraquarapt
unesp.departmentQuímica Analíticapt

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