掺杂三氧化二锑的钛酸铋钠钾陶瓷的显微结构和电学性能

采用固相合成工艺制备了（1–x）[0.82Bi0.5Na0.5TiO3–0.18Bi0.5K0.5TiO3]–xSb2O3（BNKT–xSb）压电陶瓷,研究了Sb2O3掺杂对BNKT陶瓷的显微结构和电学性能的影响规律。研究表明：Sb2O3掺杂量x小于0.020时,不改变基体的钙钛矿结构,且Sb具有可变化合价,能形成＂施主＂和＂受主＂2种掺杂而起到＂软化＂或＂硬化＂的作用。当Sb2O3掺杂量x≤0.005时,其压电系数d33随Sb2O3掺杂量的增加而增大,此时Sb2O3表现出了＂软化＂的特征;当Sb2O3掺杂量x〉0.005时,d33降低,从而又表现出了＂硬化＂的特性;当Sb2O3掺杂≥0.010时,诱使陶瓷室温下反铁电微畴的形成,导致铁电性和压电性的骤减。

Microstructure and Electrical Properties of Antimony Trioxide Doped Potassium Sodium Bismuth Titanate Ceramics

(1–x)[0.82Bi 0.5 Na 0.5 TiO 3 –0.18Bi0.5 K0.5 TiO3]–xSb 2 O 3 (BNKT–xSb) ceramics were prepared by a conventional solid-state solution technique. The influence of Sb 2 O 3 additive on the microstructure and electrical properties of the BNKT–xSb ceramics was investigated. The BNKT–xSb ceramics appeared a pure perovskite structure in the whole range of Sb 2 O 3 (x<0.020). Sb 2 O 3 might act as a "donor" or an "acceptor" in this piezoelectric ceramics due to its variable valences, which could change the electrical properties to "soft" or "hard". When x≤0.005, the piezoelectric coefficient (d 33 ) of BNKT–xSb increased with the increase of Sb 2 O 3 content, which is a characteristic of the "soft" doping. On the contrary, a "hard" property was induced when x>0.005 at which d 33 decreased again. The ferroelectric and piezoelectric properties of BNKT–xSb ceramics changed when x≥0.010, which could be correlated to the formation of anti-ferroelectric micro-domains at room temperature.