晶粒与晶界对BaTiO_3基陶瓷PTC效应的协同调制研究

Coordinating Control of the PTC Effect on BaTiO_3 Based Ceramics by Grain and Grain Boundary

采用传统的固相法,制备了Y、Mn共掺杂的BaTiO_3陶瓷。利用X射线衍射仪、扫描电子显微镜和能谱仪分别对样品的物相、微观结构和化学组分进行表征,并测量了样品的电学参数。结果表明:Y掺杂能有效降低陶瓷的室温电阻,但过量的Y会在晶界处偏析,其与晶界上的Mn相互作用,削弱正温度系数(PTC)效应。通过晶粒和晶界的协同作用,可有效调控BaTiO_3陶瓷的PTC效应。

Y and Mn co-doped BaTiO3 ceramics were prepared by the conventional solid state reaction. The phases, microstructures and composition of the prepared samples were characterized by X-ray diffractometer, scanning electron microscope and energy dispersive spectrometer, respectively, and the electrical parameters were measured. Results show that the room temperature resistance of BaTiO3 could be effectively decreased by Y doping. However, the excessive Y would segregate at the grain boundary, which weakens the positive temperature coefficient （PTC） effect of BaTiO3 ceramic, due to the interaction with Mn at the grain boundary. Through the coordinating behavior of grain and grain boundary, the PTC effect of BaTiO3 ceramic could be efficiently regulated.