Zirconia Pressure Sensors: From Nanopowders to Device

Yttria-doped zirconia nanopowders have been obtained using the hydrothermal procedure starting from soluble inorganic salts. The mechanisms and kinetics of the process have been studied to obtain high purity powders with a crystalline size range of 4 to 22nm and specific surface near 200 m2/g. These powders have been have been used to obtain membranes with controlled thickness and with densities over 95% of the theoretical value by employing the tape casting technique using organic binders, dispersants and surfactants. The influence of the additives and sintering regime on the density and microstructure of membranes has been studied. The ionic conductivity of the materials was investigated and modelled. Different types of ruthenate pastes were used to obtain thick resistive films on the zirconia membranes and interactions between the substrate and membranes were studied. Finally the gauge characteristics of the device and possibilities for applications as mechanical pressure sensors with high sensitivity are discussed.