锰掺杂无铅压电陶瓷(Bi0.5Na0.5)0.9Ba0.07Sr0.03TiO3的结构和电学性能(英文)

STRUCTURE AND ELECTRICAL PROPERTIES OF Mn-DOPED LEAD-FREE PIEZOELECTRIC CERAMICS(Bi_(0.5)Na_(0.5))_0.9Ba_(0.07)Sr_(0.03)TiO_3

采用传统陶瓷工艺制备掺MnO2的(Bi0.5Na0.5)0.9Ba0.07Sr0.03TiO3(BNBST)无铅压电陶瓷。锰掺杂(MnO2摩尔掺量x=0～1.25%)可以提高陶瓷的烧结性能,在1150℃烧结,可以得到致密陶瓷和纯的钙钛矿相。X射线衍射显示:室温、0.20<x<0.75时,形成四方相与三方相共存的准同型相界(morphotropic phase boundary,MPB),且x=0.25时,锰掺杂的BNBST陶瓷表现出优良的性能,其中压电常数d33=157pC/N,平面机电耦合系数kp=33%,机械品质因数Qm=364,相对介电常数εr=843,介电损耗tanδ=2%。这些结果确认了MPB组成与x之间的相互关系,并为设计新型压电材料提供方法。

Lead-free piezoelectric ceramics（Bi0.5Na0.5）0.9Ba0.07Sr0.03TiO3（BNBST） doped with MnO2 were fabricated with the solid-state reaction technique.With Mn（x（MnO2） = 0-1.25%,mole fraction,the same below） doping,all the ceramics can be well sintered at 1 150 ℃ and exhibit a dense and pure perovskite structure.The X-ray diffraction patterns indicate that a morphotropic phase boundary（MPB） between tetragonal and rhombohedral phases exists at 0.20x0.75,and the Mn-doped BNBST ceramic with x = 0.25 exhibits excellent properties,where piezoelectric constant d33 = 157 pC/N,electromechanical coupling factor kp = 33%,mechanical quality factor Qm = 364,relative dielectric constant εr = 843,and dielectric loss tan δ = 2%.These results confirm the relationship between the MPB composition and x and thus provide a method for designing new piezoelectric materials.