Generation of ceramic–ceramic layered composite microstructures using electrohydrodynamic co-axial flow

In this work different loading volumes (10 and 20 vol.%) of alumina and zirconia were suspended in selected liquid carriers to prepare suspensions. These suspensions were infused through inner and outer capillaries of a co-axial nozzle arrangement, which was then subjected to an electric field. The rate at which these suspensions were perfused (flow rate) and the applied voltage was varied during the experiments. Under optimal conditions, stable cone and jet formation was achieved for selected co-flowing suspensions which subsequently breaks-up into ceramic–ceramic composite droplets. Thus, droplets containing alumina and zirconia were produced and the resulting relics were collected on quartz substrates. These were sintered at 1200 °C and analysed by optical and scanning electron microscopy. The relic size increased as a function of the volume loading and layered encapsulation (shown using SEM and EDX) of alumina by zirconia and vice-versa, using this method, is achievable.