PZT and PT screen-printed thick films

Thick films (40–80 μm) of modified lead zirconate titanate (PZT) and lead titanate (PT) are screen-printed on alumina substrates electroded with Ag–Pd. First the influence of the powder grain size distribution on film characteristics after sintering is studied. With regard to the powder preparation, two processes are used: a mixed-oxide method and a wet coprecipitation process. Then thick films characteristics are compared with bulk ceramics ones. Two main factors explain the observed differences: residual porosity of the film and lateral clamping effect of the substrate. Other piezoelectric and elastic films coefficients are estimated from a plane wave model.