Ca9Al(PO4)7 based sintered glass-ceramic for high dielectric breakdown strength

作者：Xu, Wei; Tang, Wenjing; Li, Zhengdong; Hu, Chunyuan^*; Zhong, Mingfeng^*; Zhang, Zhijie^*

来源：Journal of Non-Crystalline Solids, 2022, 589: 121644.

DOI：10.1016/j.jnoncrysol.2022.121644

• Glass-ceramic
• Dielectric breakdown strength
• Charge capture
• Ca9Al(PO4)7

A novel Ca9Al(PO4)7 (CAP) based sintered glass-ceramic has been synthesized via the glass melting process and temperature controlled crystallization. The mechanisms of high dielectric breakdown strength (DBS) of the glassceramic were analyzed by X-ray diffraction (XRD), field emission scanning electron microscopy, crystal structure and high temperature complex impedance spectroscopy. CAP has a crystal structure similar to 8-Ca3(PO4)2 (8-TCP) and a higher band gap (Egap), which makes it difficult for valence electrons to break away from binding and become free charges. At the same time, the isolated vacancy formed by Al replacing Ca becomes a capture site to prevent the transmission of free charge. Furthermore, CAP based glass-ceramic have a high activation energy of grain and grain boundary, which impedes the movement of free charges. All these endow this CAP based sintered glass-ceramic with a high DBS of 110.5 +/- 5.3 kV/mm.