INFLUENCE OF Nb_2O_5 ON THE ELECTRICAL PROPERTIES OF POROUS ZrO_2-TiO_2 CERAMIC USED AS SOIL HUMIDITY SENSOR FOR ENVIRONMENTAL MONITORING

摘要

The soil humidity sensor plays fundamental role in the monitoring of hazard areas with landflows and landslides, about which in Brazil stories exist since 1671. Nowadays, it is just known that the majority of the mass movements in the hillsides occur in rainy periods, what makes the water the most important deflagrator agent of these movements, decreasing the soil resistance, increasing its specific weight and increasing the internal pressures as well. In this direction, the sensing elements developed by Group SUCERA/LAS/INPE uses the advantages presented for ceramics, in particular metal oxides, in terms of their mechanical strength, their resistance to chemical attack and their thermal and physical stability. In this work the results of the characterization analyses of sensor elements of ZrO_2-TiO_2 doped with 1, 5, 10, 15 e 20 % Nb_2O_5 porous ceramic, sintered at 1200 ℃ are shown and discussed.