Processing of porous lead titanate and lead zirconate titanate coatings

Abstract
Porous lead titanate (PT) and lead zirconate titanate (PZT) coatings were prepared by spin coating alkoxide solutions modified with benzoic acid. Carrying out the spin coating in a humid atmosphere (>30% RH) promoted the formation of porous microstructures. The variations in the chemical structure of the alkoxide and the coating microstructure indicate that the porous microstructures developed due to phase separation induced by reaction with water and evaporation. The porosity is interconnected with a size on the order of 0.1 - 2 µm, depending on the solution composition and spinning rate. While PT and PZT formed into similar porous microstructures, only PT could be processed so that it was entirely perovskite. Residual pyrochlore on the surfaces of the porous structure persisted in PZT coatings. The porous coatings were infiltrated with a polymer to make 3-3 composite coatings.