Fabrication of FSZ Ceramics Using Solgel Method for Oxygen Sensor

Ceramics of Iron oxide added-Zirconia （FSZ） have been shyntesized from the FSZ powder prepared using solgel method. The FSZ powder was prepared from ZrCl4 and Iron （Fe） nitrate. A solution containing ZrCl4 and Fe nitrate was prepared. The concentration of Zr and Fe ions was controlled so that a solid solution consists of 10 mole% Fe2O3 and 90 mole% ZrO2 will be formed as a final product. Citric acid was added into the solution and pH of the solution was controlled using NHaOH to be 5. A sol solution was formed. The sol was then heated at 80 ℃ for about 24 h to form a xerogel. The xerogel was calcined at 600 ℃ for 3 h to get FSZ nanopowder. The nanopowder was pressed with pressure of 4 ton/cm^2 to form green pellets. The green pellets were sintered at 600 ℃ for 2 h. The sintered pellets were subjected to electrical characterization, SEM evaluation and XRD analyses. For electrical characterization, the resistance of the pellets was measured at various temperatures in atmosphere of air and nitrogen gas. The data of SEM showed that the ceramics were porous with small grains showing typical characteristics of gas sensor. The XRD data showed that the ceramics crystallized in cubic structure. The electrical data showed that the ceramics were sensitive to oxygen gas. The optimum operation temperature of the ceramics as oxygen sensor is about 440 ℃.