降温过程对BaTiO_3陶瓷本征PTC效应的影响

Effect of Cooling Process on BaTiO_3-based PTC Ceramics

在空气气氛中，于1350℃保温1h的相同条件下，采用不同的降温制度，制备了一系列BaTiO3陶瓷样品。测试了R-θ（阻-温）曲线，采用XRD以及SEM等手段，分析了样品的物相及微观形貌。实验结果表明：BaTiO3陶瓷在1200℃保温2～4h，能够获得晶粒尺寸10μm、较均匀、PTC效应相对较高（3．52×10^4）的样品。还分析了PTC效应与降温温度的关系。

A series of BaTiO3 ceramics were fabricated by soaking one hour at 1 350℃ and using different cooling schedules in air condition. The resistance versus temperature curves were measured, XRD and SEM were used to study the phases and micrographs, The results indicate that uniform grains and samples with grain size of 10μm can be obtained, and the PTC effect can be enhanced to 3,52×10^4 after maintaining the samples at 1 200℃ during cooling for 2～4 hours. The relation between PTC effect and cooling temperature is also analyzed.