Fabrication of bimorph lead zirconate titanate thick films on metal substrates via the cold sintering-assisted process

A novel process was developed for the fabrication of 5–50 µm lead zirconate titanate (PZT) thick films on metal substrates. Tape cast PZT with a methyl cellulose binder was burned out at 275 °C, humidified, and then partially densified at 300 °C by cold sintering with a wet lead nitrate liquid phase. Lamination of the green tape on dense metal foils led to incomplete densification due to constrained sintering. However, when metal foils were replaced with tape cast Cu, fully sintered PZT/Cu/PZT composites were acquired after a secondary heat treatment at 800 °C. The PZT films has a relative permittivity over 500 and a loss tangent ~12% at 100 Hz because of a Cu₂O interface between the PZT and Cu presumably formed during the cold sintering process. The polarization-electric field hysteresis loop shows a remanent polarization over 20 µC/cm², and the e_31,f of the samples is -4.7 C/m².