Microstructure and Properties of a (Bi_(0.95)Na_(0.75)K_(0.15)Li_(0.05))_(0.5)Ba_(0.05)TiO_3 Ceramic Thick Film Prepared by Electrophoretic Deposition

摘要

The changes in the microstructure and properties of a (Bi_(0.95)Na_(0.75)k_(0.15)Li_(0.05))_(0.5)Ba_(0.05)TiO_3 (BNKLT-BT) ceramic film were investigated when the ceramic film was deposited with the addition of platelike SrTiO_3 (STO) via an electrophoretic deposition method. The platelike SrTiO_3 (STO) was used as a template for inducing grain growth with a preferential orientation of [001], and as a protective plate for restraining some elements in the film from evaporating under heat treatment. The SrTiO_3 templates were found to be an effective protective layer for restraining the evaporation of volatile elements when the templates are placed on the ceramic thick film. The STO/BNKLT-BT/STO/AgPd/Al_2O_3 samples were fabricated and heated at 1170℃ for 12h. They showed a [001]-oriented texture structure and better ferroelectric properties. The textured microstructure could be observed with the occurrence of grain growth around the templates. When the maximum E (E_(max)) was 150 kV/cm, the textured film showed a remanent polarization (P_r) of 9μC/cm~2, which was larger than that of the nontextured film. The piezoelectric strain constant (d_(33)*) derived from the slope of the strain curve was 62pm/V for the textured film, which was 1.5 times that of the nontextured film.