A way for densification of lead-free BaTiO3-based/ZrO2 laminates for energy harvesting applications prepared by electrophoretic deposition

In this paper, the concept of multi-layer ceramics based on a combination of piezoelectric layers BaTiO3 (BT) or (Ba0.85Ca0.15)(Zr0.1Ti0.9)O3 (BCZT) alternated with mechanically durable ZrO2 (Z) layers is investigated. Both BT/Z and BCZT/Z laminates were successfully electrophoretically deposited (EPD) due to knowledge of the deposition kinetics of individual materials and their green densities allowing precise layer thickness control. The EPD was followed by conventional sintering (CS) or spark plasma sintering (SPS). The CS resulted in the development of cracks, pores, and significant chemical reactions at the layers interfaces in both types of laminates. Laminates sintered by SPS were crack free with suppressed or none chemical reactions at the interfaces. The mechanical properties development across layers was monitored using nanoindentation. This approach identified interlayer porosity evolution and estimated the significance of the reaction zone at the interface.