磷掺杂钛酸钡陶瓷烧结过程及介电性能的研究

Study of Sintering Behavior and Dielectric Properties of Phosphor-Doped Barium Titanate

本文研究了掺杂微量元素磷对钛酸钡陶瓷烧结过程、结构及介电性能的影响。在湿化学法合成的高纯钛酸钡超细粉中，加入0．4atm％的二异丙基亚磷酸酯（P2O5的质量分数为0．14％），不加粘合剂直接压片成型，于1150－1350℃条件下无压烧结。用SEM，TMA，XRD及低频阻抗分析仪，测试样品的烧结性能、微观形貌、晶体结构和介电性能。结果表明：由于磷的加入，晶粒边界形成BaO-TiO2-P2O5三元系液相烧结，在较长的温度下即形成致密的陶瓷，1200℃保温2h的样品致密度达到理论密度的96％：1150～1200℃烧成的陶瓷，其室温介电常数高达6100－5500；居里温度随烧结温度的降低略有下降。因此，微量磷元素的掺杂有助于改善钛酸钡陶瓷的烧结过程和提高介电性能。

In this paper, effect of phosphor-doping on the sintering behavior, microsturcture and dielectric properties of BaTiO3 was investigated. The diisopropyl phosphinate was added in the high purity BaTiO3 powder preparedby wet chemical method with the final amount of P2O5 of 0. 14% with repect to the BaTiO3. The phosphor-dopedBaTiO3 ceramics with a high-density and uniform grain size has been produced by using wet processing and pressureless sintering without any binder. SEM, TMA, XRD and an impedance analyzer were used to determine the microstructure as well as dielectirc properties. The phosphor cations could form a liqiud phase belonging to the ternarysystem BaO-TiO2-P2O5, resulting BaTiO3 ceramics with high density forming at low temperature. The phosphordoped BaTiO3 ceramics with a high density of 96% Dth was obtained by sintering at 1200℃ with soaking time 2h.The dielectric constant of samples sintered at 1150℃ and 1200℃ were as high as 6100, 5500 respectively;The Curietemperature of samples decreased with decreasing sintering temperature. Therefore, doping of a little amount of phosphor could improve the sintering and dielectric properties of BaTiO3 ceramics.