Hydrothermal and electrophoretic deposition of lead zirconate titanate (PZT) films

Hydrothermal synthesis in conjunction with colloidal processing has been used to make PZT films in an aqueous solution. Fine PZT powders with a particle size of 200 nm and a narrow particle size distribution were synthesised hydrothermally at 300°C. After washing, a dispersant (di-ammonium citrate) was added to the slurry to make a stable suspension. Electrophoretic deposition (EPD) was then employed to deposit PZT films directly from the hydrothermal PZT suspensions. The effects of the synthesis conditions on the particle size and size distribution of the PZT powders are briefly discussed. Various stabilisation mechanisms for the hydrothermal slurries have been investigated. The effects of the slurry properties and deposition parameters on the microstructure of deposited films are discussed. It is shown that PZT films with a thickness <5 μm can be deposited via EPD on Pt wires. However, the limitation of electric field, which must be below the decomposition voltage of water, resulted in an inferior packing density during deposition. The films had to be sintered at relatively higher sintering temperatures (>1000°C) in comparison with powder compacts. In addition, interaction with the substrate was observed when PZT films were deposited and sintered on Pt-coated alumina substrates.