Departamento de Ingeniería Química, Ambiental y de los Materiales

URI permanente para esta comunidadhttps://hdl.handle.net/10953/42

En esta Comunidad se recogen los documentos generados por el Departamento de Ingeniería Química, Ambiental y de los Materiales y que cumplen los requisitos de Copyright para su difusión en acceso abierto.

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Fracture behaviour of microcrack-free alumina-aluminium titanate ceramics with second phase nanoparticles at alumina grain boundaries
(Elsevier, 2008) Bueno, Salvador; Berger, Marie Hélène; Moreno-Botella, Rodrigo
Alumina + 10 vol.% aluminium titanate composites were obtained by colloidal filtration and reaction sintering of alumina and titania. The materials were dense with aluminium titanate grains of average sizes 2.2–2.4 μm located mainly at alumina triple points. The reaction sintering schedule promoted the formation of additional nanometric grains, identified as aluminium titanate using STEM–EDX analysis between the alumina grains. This special microstructure led to a change of the toughening mechanism from the typical crack bridging reported for microcrack-free composites fabricated from alumina and aluminium titanate powders to microcracking. The identification of microcracking as the main toughening mechanism was done from the analysis of stable fracture tests of SENVB samples in three points bending and fractographic observations. Monophase alumina materials with similar grain sizes were used as reference. Different fracture toughness parameters were derived from the load–displacement curves: the critical stress intensity factor, KIC, the critical energy release rate, GIC, the J-Integral and the work of fracture, γWOF, and the R curves were also built. The comparison between the linear elastic fracture parameters and the non-linear ones revealed significant toughening and flaw tolerance.
Reaction sintered Al2O3/Al2TiO5 microcrack-free composites obtained by colloidal ﬁltration
(Elsevier, 2004) Bueno, Salvador; Moreno-Botella, Rodrigo; Baudín, Carmen
Dense and microcrack-free Al2O3 / Al2TiO5 composites (10, 30 and 40 vol. % of Al2TiO5) have been obtained by colloidal filtration and reaction sintering, using alumina and titania as starting powders. The processing of the composites has been studied focusing on the rheological behaviour of aqueous suspensions of each powder and of mixtures. Colloidal filtration of optimised suspensions, with a solid loading as high as 50 vol. %, and a thermal treatment at 1450ºC, lead to completely reacted and uncracked sintered materials with homogeneously distributed aluminium titanate contents up to 40 vol. % and high density. Thermal diffusivity values from 25 to 800ºC are coincident on heating and cooling for the three studied composites, and decrease with temperature and with aluminium titanate content.

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Examinando Departamento de Ingeniería Química, Ambiental y de los Materiales por Materia "Al2TiO5"