Effect of different pore formers on the performance of lead free piezoelectric ceramics

Ceramics based piezoelectric materials with unique porous microstructure and chemical compositions are regarded suitable for advanced applications due to their distinct properties. In this work, NKN-ST [(1-x) (Na0.5 K0.5 NbO3)—x (SrTiO3)] specimens were prepared by conventional solid-state method. Using different pore forming agents such as ammonium oxalate monohydrate and graphite, porous piezoelectric ceramics were processed to obtain different porous configuration by sacrificial foaming method. Scanning electron microscopy showed a continuous structure with interconnectivity. The phase structure, dielectric and piezoelectric properties of the samples were systematically investigated on the effects upon addition of SrTiO3 content and different porogens.