Lead hafnate titanate (PHT) ceramics: processing and properties

The aim of the present paper is to investigate the processing and properties of lead hafnium and titanium based ceramic PbHfx Ti1-xO3 (x = 0.5), noted PHT. The first part is devoted to processing: powders are obtained from pyrolysis of oxalic precursor. Powder characteristics depend on the used conditions of pyrolysis, They are optimized in order to obtain an easier sintering behaviour. The second part is concentrated on physical properties of PHT such as piezoelectric, dielectric loss and permittivity and on the anelastic behaviour (mechanical loss and elastic modulus). These properties, measured as a function of temperature, allow us to show the presence of two phase transitions and the motion of domain walls in the ferroelectric phase. Furthermore, the dielectric and piezoelectric properties of PHT are similar to the PZT [Pb (Zr, Ti)O-3] ones. (C) 2000 Elsevier Science Ltd. All rights reserved.