二氧化硅掺杂钛酸锶钡陶瓷的介电性能与电卡效应

采用传统的固相反应法制备二氧化硅（SiO₂）掺杂钛酸锶钡（Ba_0.65Sr_0.35TiO₃,BST）陶瓷（BST+x%SiO₂）,研究了掺杂二氧化硅对BST陶瓷的物相、微观形貌、介电性能及电卡效应的影响。结果表明：掺杂二氧化硅并未改变BST陶瓷的晶型结构,但有助于提升晶粒的均匀性和材料介电性能频率的稳定性。随着二氧化硅掺杂量增加,BST陶瓷的介电常数呈现单调递减趋势,介电弥散特性逐渐增强。二氧化硅的掺杂有利于提升BST陶瓷的电卡性能,其中BST+3%SiO₂陶瓷具有最优的电卡效应,在30 ℃下可获得最大电卡绝热温变（ΔT_max）,ΔT_max和ΔT_max/ΔE分别为1.6 ℃、8.00×10 ^-7 ℃·m/V,电卡效应半峰宽（T_span）为10 ℃左右。

Dielectric properties and electrocaloric effect of SiO2 doped Ba0.65Sr0.35TiO3 ceramics

SiO₂ doped barium strontium titanate（Ba_0.65Sr_0.35TiO₃,BST） ceramics（BST+x%SiO₂ ） were prepared by traditional solidstate reaction method.The effects of SiO₂ doping on the phase,morphology,dielectric properties and electrocaloric effect of BST ceramics were studied.The results showed that doping SiO₂ didn′t change the crystal structure of BST ceramics,but improved the uniformity of grain and the frequency stability of dielectric properties of BST ceramics.With the increase of SiO₂ content,the dielectric constant decreased monotonously,the dielectric dispersion characteristics increased gradually.The doping of SiO₂ was beneficial to improve the electrocaloric performance of BST ceramics.Among them,BST+3% SiO₂ ceramic possessedthe best electrocaloric effect,and the temperature of the maximum electrocaloric adiabatic temperature change （ΔT_max) was 30 ℃.Its ΔT_max and ΔT_max/ΔE were 1.6 ℃ and 8.00×10 ^-7 ℃·m/V respectively,the half-width of the electrocaloric effect（T_span）was about 10 ℃.