Microstructure, electrical and humidity sensing properties of light rare earths zirconates

Light rare earths zirconates Ln2Zr2O7 (Ln = La, Nd, Sm, Eu, and Gd) from preparation to sensor application are analyzed. The materials were produced by liquid route and dried through three calcinations processes. XRD and SEM investigations were used to certify the composition and microstructure. The electrical investigation on different humidity conditions was performed at different frequency in order to highlight rare earths zirconates compositions suitable for sensor applications. Humidity sensors with light rare earths zirconates as active elements were investigated, obtaining high sensitivities, short response and recovery times, especially for zirconates materials with Ln elements based on right side of light rare earths group. The correlation between sensors characteristics and active material properties are also investigated. Due their high chemical and physical stability, humidity sensors based on light rare earths zirconates compositions are useful for monitoring corrosive environments.