Stabilizing the anti-ferroelectric phase in NaO–Nb2O5–CaO–B2O3–SiO2–ZrO2 glass-ceramics using the modification of K+ ion

Abstract

NaNbO3 anti-ferroelectric (AFE) material exhibits a unique and irreversible phase transition, which makes it change into ferroelectric phase and prevents its implementation in high energy storage material. In this work, we use an approach to stabilize the anti-ferroelectric phase at room temperature by the modification of K+ in NaO–Nb2O5–CaO–B2O3–SiO2–ZrO2-xK + glass-ceramics. The correlation between K+ content and anti-ferroelectric stability is studied through the X-ray diffraction, microstructure, and dielectric properties. It is found that ferroelectric phase gradually transforms to anti-ferroelectric phase first and then anti-ferroelectric phase disappears with K+ doping in glass-ceramic due to two mechanisms that the un-crystallized modifier K+ into glass network reduce the connectivity of the glass network, the activation energy needed for crystallization and the tolerance factor (t), besides overmuch K+ into NaNbO3 crystalline phase leads to the increase of tolerance factor and the production of impurity phase. The phase transition has been confirmed through the double polarization loops, AFE phase and permittivity peak. The results show that the K+ doped into NaO–Nb2O5–CaO–B2O3–SiO2–ZrO2-xK + glass system can effectively stabilize AFE phase, when x＞4%, the stability of NaNbO3 anti-ferroelectric phase will decrease and impurity phases will precipitate in glass-ceramic.