Fluorine as a donor dopant in barium titanate ceramics

摘要: We have studied the electrical properties and microstructure of fluorine-doped BaTiO3 ceramics. The samples were prepared using a classical ceramic technology that involved calcination intimately mixed powders BaCO3, TiO2, BaF2. When sintered in untreated ambient air, fluorine from sample reacted with water vapor formed gaseous HF. To prevent this hydrolysis fluorine, we dried air. ceramics dry atmosphere showed microstructures typical donor-doped BaTiO3. containing up to 0.3 mol% coarse-grained, semiconducting, displayed remarkable PTCR effect. In contrast, higher concentration fine grained insulating. A SIMS elemental mapping was distributed throughout semiconducting samples; however, enriched at grain boundaries BaTi2O5 intergranular phase.