Ag^+掺杂钛酸锶钡基玻璃陶瓷的显微结构和介电性能

Microstructure and Dielectric Properties of Silver Ions Doped BST Glass Ceramic

采用熔融法制备了钛酸锶钡(barium strontium titanate,BST)基玻璃,然后将此玻璃样品在不同的温度下进行热处理得到BST基玻璃陶瓷,采用差热分析研究了BST基玻璃陶瓷析晶过程中的热力学特征,用扫描电子显微镜和X射线衍射分别分析了玻璃陶瓷的显微结构和相结构,并且系统研究了该玻璃陶瓷的介电特性以及耐击穿电场强度。结果表明:0.3%(质量分数)Ag+掺杂时,BST基玻璃中BST相的析晶温度从885℃下降到840℃,有利于玻璃体中BST晶体的析出。另外,Ag+的掺杂有利于提高BST基玻璃陶瓷的介电常数,同时能维持较低的介电损耗。此外,Ag+掺杂能够提高BST基玻璃的耐击穿电场强度,其在800℃热处理后,可达96.3 kV/mm,高于未掺杂Ag+的BST基玻璃的52.5kV/mm。

Barium strontium titanate（BST） based glass was prepared by a melting method,and then the glass samples were heat treated under different process conditions to obtain the BST based glass ceramics.The thermodynamic characteristics during the process of crystallization were investigated by differential scanning calorimeter.The microstructure and phase structure of glass ce-ramics were analyzed by scanning electron microscopy and X-ray diffraction,respectively.Moreover,the dielectric properties of glass ceramics and the breakdown strength were determined.The results show that the doping of a certain amount（i.e.,0.3% in mass） of Ag＋ ion can reduce the crystallization temperature from 885 to 840 ℃,which is conducive to the precipitation of the BST.Also,the doping of Ag＋ ion enhanced the dielectric constant of the BST based glass ceramics and maintained a low level of dielectric loss.In addition,the doping of Ag＋ ion improved the breakdown strength,i.e.,the samples heated at 800 ℃ had the breakdown strength of 96.3 kV/mm,which was higher than that of the undoped BST based glass（52.5 kV/mm）.