钛酸铋钠基陶瓷的冷烧结制备及介电性能

Cold Sintering Preparation and Dielectric Properties of Bismuth Sodium Titanate-Based Ceramics

冷烧结(CSP)工艺是近年来新兴的一种高效、节能的材料方法。本工作采用CSP工艺,制备出致密度不低于97%的(1–x)BNT–x NN电介质陶瓷。研究了CSP工艺和Na Nb O_(3)含量对(1–x)BNT–x NN复相陶瓷的密度、相结构、显微形貌和介电性能的影响。结果表明:CSP工艺由于烧结温度低、保温时间短,可以显著降低晶粒尺寸,有效抑制Bi、Na等元素挥发,从而提高介电常数,降低介电损耗。随着Na Nb O_(3)含量的增加,(1–x)BNT–x NN复相陶瓷的剩余极化强度显著降低,并且介电常数的温度稳定性显著提升。当x=0.3时,0.7BNT–0.3NN陶瓷样品在25℃至400℃宽温范围内介电常数的变化率小于±6%,介电损耗小于5%,这表明CSP技术制备的(1–x)BNT–x NN陶瓷有望应用于温度稳定性陶瓷电容器。

Cold sintering process (CSP) is an efficient and energy saving sintering method emerging in recent years.In this paper,the(1–x)BNT–x NN dielectric ceramics with the density of more than 97%were prepared by CSP.The effect of CSP parameters and Na Nb O_(3) content on the density,phase structure,microstructure,and dielectric characteristics of (1–x)BNT–x NN ceramics were investigated.The results show that the CSP can drastically reduce the grain size and prevent some components like Bi and Na from volatilizing due to low sintering temperature and short holding time,thereby increasing the dielectric constant and reducing the dielectric loss.The remnant polarization decreases,and the temperature stability of dielectric constant increases as the content of Na Nb O_(3) increases.When x=0.3,the variation in dielectric constant of the 0.7BNT–0.3NN ceramic is less than 6%at 25-400℃,and the dielectric loss is less than 5%.It is indicated that the (1–x)BNT–x NN ceramics prepared by CSP are one of the promising candidates for the applications in temperature-stability ceramic capacitors.