Abstract
Uniformly porous and porosity-graded piezoelectric ceramics were prepared by sintering powder compacts consisting of lead zirconate titanate (PZT) and organic material powders as pore-forming agents (PFA) in air atmosphere. Three kinds of PFA materials, such as, stearic acid, polymethyl methacrylate (PMMA) and urea, were compared, and PMMA was revealed to be most suitable for controlling the porosity of PZT ceramics. The experiments were focused on the influences of PFA and its amount on the porosity of the sintered PZT. The dielectric, elastic and piezoelectric properties of uniformly porous PZT ceramics were investigated as a function of the porosity volume fraction. Furthermore, beam-shaped PZT actuator samples with graded porosity across thickness were fabricated by sintering PFA-graded powder compacts, and their electric-field-induced deflection characteristics were measured and compared with the values calculated from the modified classical laminate theory using the elastic and piezoelectric constants of the non-FGM porous PZT ceramics.
