Aqueous aluminium titanate paste for the liquid deposition modelling

Advanced ceramic pastes, based on precursor of aluminium titanate (tialite, Al2TiO5), were prepared in two steps by ball milling starting from an aqueous slurry and with the addition of a thickener. Rheological behaviour of the prepared slurries and pastes with different formulations were analysed up to identify a tialite based paste with shear thinning behaviour and yield stress value suitable to be 3D printed by Liquid Deposition Modeling (LDM). In particular, printable pastes with a solid content up to 51 vol% were prepared. Shaping of aluminium titanate green bodies was realized both by LDM and conventional pressing to compare the properties of the sintered materials. Both shaping processes lead to a porous tialite with density value of 67.6 ± 0.7% for 3D printed tialite and of 75.6 ± 0.1% for pressed tialite. Furthermore, the morphology and thermogravimetric analysis of ceramic powder before and after ball milling were performed. Physico-chemical, microstructure and thermomechanical characterization of the obtained sintered material demonstrated that the LDM technique can be used to manufacture tialite starting from a suitable formulation of the ceramic paste. Moreover, the thermomechanical tests confirmed higher mechanical strength for pressed tialite; after a thermal shock treatment at 400 °C both 3D printed and pressed tialite shown a moderate decrease of mechanical properties.