Development of zirconia-titania porous ceramics for humidity sensors

Porous ZrTiO4 ceramic specimens were prepared by pressing and sintering at different temperatures (1150–1500 °C range) powders synthesized by the polymeric precursor technique. X-ray diffraction analysis shows that all specimens are orthorhombic single-phase ZrTiO4. Average pore diameter had approximately 73% reduction for increasing the sintering temperature from 1150 to 1500 °C. Scanning electron micrographs of polished and thermally etched surfaces show also intergranular porosity reduction at the expenses of the increase of average grain size. Impedance spectroscopy measurements in specimens under controlled humidity conditions gave evidences of the ability of the porous ZrTiO4 specimens to be used as humidity sensors.