摘要
In this study,high Curie Temperature(T_(c))perovskite ceramics of optimized composition 0.55(0.1BiYbO_(3)-0.9PbTiO_(3))-0.45PbZrO_(3) with unique double orthorhombic main phases were prepared by a modified solgel method.Compared to the usual solid-state prepared sample,the sol-gel derived sample has a 1.6 times higher d_(33) of 325 pC/N,a 2.4 times higher remnant polarization,and a much better high temperature stability with similar depolarization temperature(T_(d))and T_(c).Comprehensive analysis of the xerogel prepared over a wide calcination temperature(T_(cal))range of 300-1000℃ revealed that perovskite structure appeared at only 400℃ and it became the main phase above 500℃.Comparison of XRD refinement results showed that calcination and sintering induced subtle and continuous phase transition,namely,the 400-900℃ calcined powders with coexisted tetragonal(P4mm)and orthorhombic(Pbam)phase changed to a rather stable double orthorhombic(Pmmm and Pbam)main phase in all the differently sintered ceramics,as similar to the 1000C calcined powders.The stable phase coexistence well explains the enhanced performance.The results also demonstrate that optimized sol-gel processing can provide high T_(c) ceramics with desirable multi-phase structure and significantly enhanced performance at a lower temperature.
基金
supported by the National Natural Science Foundation of China(Grant No.11574346)
the Fundamental Research Funds for the Central Universities
the Fund of Key Laboratory of Advanced Materials of Ministry of Education(Grant No.218AML07)
the Open Foundation of the State Key Laboratory of New Ceramics and Fine Processing of Tsinghua University(KF201809).
