Porous Barium Titanate Ceramics

Significant electrical resistance change due to gas and humidity absorbtion on metal oxide semiconductor surface has been known for long. Pure BaTiO3, which is an insulator at room temperature, could be made semiconductor by incorporation of low amount of donor ion oxides.The aim of the present study is to fabricate BaTiO3 with desired properties by investigating relationship between defect chemistry and characteristics. BaTiO3 based bulk ceramics were produced enhancing the porosity percentage by addition of different amounts of graphite and PMMA powders into La+3 doped BaTiO3 ceramics. For electrical conductivity measurements, to provide humidity environment, evaporation apparatus and gas-tight humidity chamber were used. By using apparatus, electrical resistance measurements under humid environment were carried out on samples with all compositions. For relative humidity percentages between 0-100%, for each humidity percentage an electrical resistance value was read. Special attention was paid for proton conductivity and applications for humidity sensing.