Low temperature processing of nanocrystalline lead zirconate titanate (PZT) thick films and ceramics by a modified sol-gel route

Dispersing fine particles into a sol-gel matrix is a promising process to get a thick 0-3 composite coating layer. In this paper, we have further improved this modified sol-gel process by nanocrystalline composite technique to realize the low temperature annealing. Dense Pb(Zr, Ti)O₃ (PZT) thick films of 10 to 50 μm in thickness have been obtained on the platinum-coated silicon substrates by spin-coating at sintering temperature of 600-700°C and fully developed submicron-sized grains have been demonstrated in screen-printing piezoelectric films on alumina substrates at sintering temperature of 700-800°C. The dependence of various properties such as microstructure, crystallization, ferroelectric and dielectric properties of such made thick films on the processing parameters have been investigated. For a 10 μm-thick film spin-coated on silicon wafer, the dielectric loss and relative permittivity are 0.010 and 1024, respectively, at 1 kHz. The remanent polarization (Pr) and the coercive field (E_c) are 13.6 μC/cm² and 34.5 kV/cm, respectively. Obviously, such made thick film has comparable properties with bulk PZT ceramic. This novel technique can be extensively used in sol-gel, screen-printing, tape-casting, even in traditional ceramic process to reduce the process temperature.