Lead‐free MnO‐doped 0.955K_0.5Na_0.5NbO₃‐0.045Bi_0.5Na_0.5ZrO₃ (abbreviate as KNN‐0.045BNZ) ceramics have been prepared by a conventional solid‐state sintering method in reducing atmosphere. The MnO addition can suppress the emergence of the liquid phase and improve the homogenization of grain size. All ceramics sintered in reducing atmosphere show a two‐phase coexistence zone composed of rhombohedral (R) and tetragonal (T) phase. MnO dopant results in the content increase in R phase and slight increase in Curie temperature T_C. For KNN‐0.045BNZ ceramics, Mn²⁺ ions preferentially occupy the cation vacancies in A‐site to decrease oxygen vacancy concentration for 0.2%‐0.4% MnO content, whereas Mn²⁺ ions substitute for Zr⁴⁺ ions in B‐site to form oxygen vacancies at x ≥ 0.5. The defect dipole is formed at the moderate concentration from 0.5 to 0.6, which can provide a preserve force to improve the temperature stability of piezoelectric properties for k_p and . The Mn0.4 ceramics show excellent electrical properties with quasistatic piezoelectric constant d₃₃ = 300 pC/N, electromechanical coupling coefficient k_p = 51.2%, high field piezoelectric constant  = 430 pm/V (at E_max = 25 kV/cm) and T_C = ~345°C, insulation resistivity ρ = 6.13 × 10¹¹ Ωcm.

中文翻译：

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在还原气氛中烧结的MnO掺杂KNN基陶瓷的温度稳定性和电性能

无铅MnO掺杂0.955K _0.5 Na _0.5 NbO ₃ -0.045Bi _0.5 Na _0.5 ZrO ₃（缩写为KNN-0.045BNZ）陶瓷是通过传统的固态烧结方法在还原气氛中制备的。MnO的添加可以抑制液相的出现并改善晶粒尺寸的均质化。在还原性气氛中烧结的所有陶瓷都显示出由菱面体（R）和四方体（T）相组成的两相共存区。MnO掺杂导致R相含量增加，居里温度T _C略有增加。对于KNN-0.045BNZ陶瓷，Mn ²⁺离子优先占据A部位的阳离子空位减少氧空位浓度为0.2％-0.4％的MnO含量，而锰²⁺离子取代的Zr ⁴⁺在B位离子以形式的氧空位X  ≥  0.5。缺陷偶极子在0.5到0.6的中等浓度下形成，可以提供保持力来改善k _p和k的压电特性的温度稳定性。Mn0.4陶瓷具有优异的电性能，准静态压电常数d ₃₃  = 300 pC / N，机电耦合系数k _p  = 51.2％，高场压电常数 = 430点/ V（在Ë_最大 = 25千伏/厘米）和Ť _Ç  =〜345℃，保温电阻率ρ= 6.13×10 ¹¹ Ω厘米。