Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1490395 | Materials Research Bulletin | 2012 | 6 Pages |
Alumina–aluminium titanate (A–AT) composites are typically produced either by mixing the alumina matrix powder with already formed aluminium titanate or by reaction sintering of alumina and titania powders. Reaction-sintered materials usually exhibit limited final density and extensive microcracking. This paper describes the preparation of A–AT nanocomposites by slip casting and reaction sintering, using aqueous suspensions of submicrometre-sized alumina and nanometre-sized titania at a respective weight ratio of 87:13, which is typical for plasma-sprayed coatings. The colloidal stability of aqueous suspensions of the two individual powders and of their respective mixtures was determined first, measuring zeta potential and rheological behaviour as a function of deflocculant content and sonication time. The bimodal distribution yielded green relative densities of up to 70% of theoretical density. Dynamic and static sintering studies showed that aluminium titanate had already formed at 1400 °C.
Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Low viscosity suspensions with low thixotropy were prepared to a final solids loading of 55 vol.%. ► The bimodal distribution led to green relative densities of up to 70% of theoretical density. ► Reaction sintering of submicrometre-sized alumina and nanometre-sized titania (87:13).