Processing of high performance lead lanthanum zirconate titanate thick films

The processing and ferroelectric properties of lead lanthanum zirconate titanate (PLZT) thick films on Pt-coated Al2O3 substrate were studied. The most critical processing issue is to prevent lend losses during heat treatment. Maintaining a high PbO vapour concentration during heat treatment of the layers maintains a liquid phase that enables densification also in constrained conditions, possibly because of relaxation of the shear stress originating from constrained sintering. Reaction of PbO-rich liquid phase at the platinum/alumina interface results in p-alumina crystals that deteriorate the contact between the platinum electrode and the substrate. Instead of platinum on Al2O3, a new Al2O3/PLZT/Pt structure was introduced taking advantage of the excellent mechanical stability of the Al2O3/PLZT and Pt/PLZT interfaces. PLZT thick films with ferroelectric properties equal to or better than those of hot pressed samples were obtained. Such a sintering and electrode strategy can be applied in processing of other lead-based thick films. (C) 1999 Elsevier Science Limited. All rights reserved.