Preparation of Dense Piezoelectric PbNb2O6 Ceramics from Powders with Low-Temperature Form

The effect of microstructure on dielectric and piezoelectric properties of PbNb2O6 was studied to examine the possibility of using powder with the low-temperature rhombohedral form for the preparation of piezoelectric PbNb2O6 ceramics. Dense, fine-grained PbNb2O6 ceramics with good piezoelectric property with the maximum kt value of 0.315 were obtained by rapid heating and isothermal soaking at 1250°C of powders with particle size between 0.7 and 1.0 μm. The use of coarse powder resulted in the development of large grains and pores caused by exaggerated grain growth induced by phase transformation from the low- to high-temperature forms. Isothermal soaking at 1300°C resulted in the formation of a duplex structure. These structural defects reduced the piezoelectric property.