From rapid prototyping to rapid firing: on the feasibility of high‐speed production for complex BaTiO3 components

Abstract

AbstractDirect ink writing (DIW) is an attractive additive manufacturing (AM) technology because of its simplicity, production speed, and feedstock flexibility; in addition, the use of a limited amount of binder makes the subsequent thermal debinding process easy. Nevertheless, the conventional approach to debind and sinter AMed components remains extremely slow, representing a bottleneck in the manufacturing process. In order to address such limitation, we explored different rapid sintering strategies: ultrafast high‐temperature sintering (UHS), pressureless spark plasma sintering (P‐SPS), and fast firing (FF), for the densification of BaTiO3 components fabricated by DIW, one of the widely used lead‐free piezoceramics. All sintering technologies allow debinding and sintering of crack‐free components in a few minutes instead of several hours. The final density and microstructure are strongly dependent on the sintering atmosphere (inert for UHS and P‐SPS, air for FF) and a maximum relative density of only ≈72% was obtained when firing occurred in an inert environment, irrespective of the sintering technique (UHS and P‐SPS). An undesired phase transition from tetragonal to hexagonal BaTiO3 was also observed upon UHS and ‐PSPS. On the contrary, FF in air yielded a density of about 95% in a few minutes while maintaining the desired tetragonal polymorph. The results provide proof of feasibility for rapid processing of BaTiO3 components obtained by DIW.