Microstructure and Electrical Properties of BaTiO_3-Based PTC Ceramics Prepared from Nanopowders

摘要

Dense PTC ceramics were prepared with BaTiO_3 nanopowders synthesized by hydrothermal method. BaCO_3 and Ti(OC_4H_9)_4 were used as barium and titanium sources, and Y(NO)_3·6H_2O as the donor dopant respectively. The average grain size of the powders obtained after hydrothermal treatment at 160℃ for 9h was about 30nm with cubic structure. Mn(NO_3)_2 was introduced to the as-prepared nanopowders in order to improve the PTC effect. After sintered at 1280℃, the PTC ceramic samples exhibited sufficient resistance jump ratio( 1.086×10~3) around Curie temperature, the density of which was 5.81g/cm~3(96.5% of the theoretical density).