Electrical and mechanical properties of piezoelectric ceramic/metal composites in the Pb(Zr,Ti)O3/Pt system

As a model for composite materials of piezoelectric ceramic and metal, lead zirconate titanate (PZT) and platinum (Pt) particulate composites were fabricated by power processing. The electrical and mechanical properties of the PZT-Pt composites were measured as a function of the Pt volume fraction. The relative dielectric constants of the PZT-Pt composites increased markedly, while the piezoelectric constants and electromechanical coupling coefficients decreased with increasing Pt content. When the Pt volume fraction exceeded 30%, the PZT-Pt composite became electrically conductive because of percolation of the Pt particles. The Pt-dispersed PZT composites enhanced the mechanical properties, particularly the high fracture resistance, compared to the monolithic PZT ceramics. (C) 2001 American Institute of Physics.