BaTiO_3陶瓷中Nb_2O_5-Zn_(0.8)Mg_(0.2)TiO_3的掺杂效应

Dopping Effects of Nb_2O_5-Zn_(0.8)Mg_(0.2)TiO_3 in BaTiO_3 Ceramics

研究了BaTiO3-Nb2O5-Zn0.8Mg0.2TiO3系统的介电性能及微观性能。SEM和XRD分析发现,在掺杂x(Nb)=1%的BaTiO3陶瓷中,Zn0.8Mg0.2TiO3的固溶度小于4%。Nb2O5和Zn0.8Mg0.2TiO3用量均为1%时,BaTiO3陶瓷为赝立方相结构,当x(Nb)>2%时,陶瓷样品(002)和(200)衍射峰相互分开,研究表明,BaTiO3陶瓷为四方相,且随着Nb用量增加,四方率增强。此外,Nb用量增加还使BaTiO3陶瓷室温介电常数降低,而同时居里点升高。当x(Nb)=2%和x(ZMT)=1%时,在空气中于1 180℃下烧成的BaTiO3陶瓷材料的主要性能指标为:298 K时介电常数2ε98 K=2 004,介电损耗tanδ=0.84%,密度ρ=1.4×1012Ω.cm,-55^+150℃,电容量温度变化率△C/C≤±15%。

This paper investigated the micro-properties and dielectric properties of BaTiO3-Nb2O5-Zn0.8Mg0.2TiO3 system. The SEM and XRD analysis showed that the solubility of Zno.s Mg0. 2 TiO3 in BaTiO3 with 1% Nb dopant is less than 4%. With only 1% Nb doping, the sample showed pseudo-cubic structure. Nevertheless, when Nb amount exceeded 2%, the room-temperature structure of doped BaTiOa was tetragonal, as evidenced by the （002） and （200） peaks were separated from each other, and the tetragonality became stronger with Nb concentration increasing, when Zno.s Mgo.2 TiO3 amount was identical, with Nb concentration increasing, dielectric constant decreased and the Curie temperature shifted to higher temperatures. For the sample with 2% Nb and 1% ZMT, the main features of the BaTiO3 ceramics that were sintered in air atmosphere at 1 180 ℃ are： ε298K =2 004, tan δ=0.84%,ρ=1. 4×10^12Ω·cm, -55～＋150℃ and ΔC/C≤15%.