Yang Jun, Pang Jinbiao, Luo Xiaofang, Ao Laiyuan, Xie Qiang, Wang Xing, Yang Hongyu, Tang Xianzhong
School of Materials and Energy, University of Electronic Science and Technology of China, Chengdu 611731, China.
China Zhenhua Group Yunke Electronic Co., Ltd., Guiyang 550018, China.
Materials (Basel). 2023 Jul 24;16(14):5195. doi: 10.3390/ma16145195.
This work studied the phase constitution, bond characteristics, and microwave dielectric performances of SrTiO ceramics. Based on XRD and Rietveld refinement analysis, pure tetragonal Ruddlesden-Popper type SrTiO ceramic is synthesized at 1425~1525 °C. Meanwhile, the microstructure is dense and without porosity, indicating its high sinterability and densification. Great microwave dielectric performances can be obtained, namely an value of 39.41, and a value of 93,120 GHz, when sintered at 1475 °C. Under ideal sintering conditions, the extrinsic factors are minimized and can be ignored. Thus, the intrinsic factors are considered crucial in determining microwave dielectric performances. Based on the P-V-L complex chemical bond theory calculation, the largest bond ionicity, and proportions to the bond susceptibility from Sr-O bonds suggest that Sr-O bonds mainly determine the dielectric polarizability. However, the Ti-O bonds show lattice energy about three times larger than Sr-O bonds, emphasizing that the structural stability of SrTiO ceramics is dominated by Ti-O bonds, and the Ti-O bonds are vital in determining the intrinsic dielectric loss. The thermal expansion coefficient value of the SrTiO structure is also mainly decided by Ti-O bonds.
本工作研究了SrTiO陶瓷的相组成、键特性和微波介电性能。基于XRD和Rietveld精修分析，在1425~1525℃合成了纯四方Ruddlesden-Popper型SrTiO陶瓷。同时，其微观结构致密无孔隙，表明其具有高烧结性和致密化特性。在1475℃烧结时，可获得优异的微波介电性能，即 值为39.41， 值为93120 GHz。在理想烧结条件下，外在因素最小化且可忽略不计。因此，内在因素被认为对确定微波介电性能至关重要。基于P-V-L复合化学键理论计算，Sr-O键的最大键离子性及其与键极化率的比例表明，Sr-O键主要决定介电极化率。然而，Ti-O键的晶格能比Sr-O键大约大三倍，这表明SrTiO陶瓷的结构稳定性由Ti-O键主导，且Ti-O键对确定本征介电损耗至关重要。SrTiO结构的热膨胀系数值也主要由Ti-O键决定。
